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 #include "ospfd/ospf_bfd.h"
  52
  53 static void nsm_clear_adj (struct ospf_neighbor *);
  54
  55 /* OSPF NSM Timer functions. */
  56 static int
  57 ospf_inactivity_timer (struct thread *thread)
  58 {
  59   struct ospf_neighbor *nbr;
  60
  61   nbr = THREAD_ARG (thread);
  62   nbr->t_inactivity = NULL;
  63
  64   if (IS_DEBUG_OSPF (nsm, NSM_TIMERS))
  65     zlog (NULL, LOG_DEBUG, "NSM[%s:%s]: Timer (Inactivity timer expire)",
  66           IF_NAME (nbr->oi), inet_ntoa (nbr->router_id));
  67
  68   OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_InactivityTimer);
  69
  70   return 0;
  71 }
  72
  73 static int
  74 ospf_db_desc_timer (struct thread *thread)
  75 {
  76   struct ospf_neighbor *nbr;
  77
  78   nbr = THREAD_ARG (thread);
  79   nbr->t_db_desc = NULL;
  80
  81   if (IS_DEBUG_OSPF (nsm, NSM_TIMERS))
  82     zlog (NULL, LOG_DEBUG, "NSM[%s:%s]: Timer (DD Retransmit timer expire)",
  83           IF_NAME (nbr->oi), inet_ntoa (nbr->src));
  84
  85   /* resent last send DD packet. */
  86   assert (nbr->last_send);
  87   ospf_db_desc_resend (nbr);
  88
  89   /* DD Retransmit timer set. */
  90   OSPF_NSM_TIMER_ON (nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
  91
  92   return 0;
  93 }
  94
  95 /* Hook function called after ospf NSM event is occured.
  96  *
  97  * Set/clear any timers whose condition is implicit to the neighbour
  98  * state. There may be other timers which are set/unset according to other
  99  * state.
 100  *
 101  * We rely on this function to properly clear timers in lower states,
 102  * particularly before deleting a neighbour.
 103  */
 104 static void
 105 nsm_timer_set (struct ospf_neighbor *nbr)
 106 {
 107   switch (nbr->state)
 108     {
 109     case NSM_Deleted:
 110     case NSM_Down:
 111       OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
 112       OSPF_NSM_TIMER_OFF (nbr->t_hello_reply);
 113     case NSM_Attempt:
 114     case NSM_Init:
 115     case NSM_TwoWay:
 116       OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
 117       OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
 118       OSPF_NSM_TIMER_OFF (nbr->t_ls_req);
 119       break;
 120     case NSM_ExStart:
 121       OSPF_NSM_TIMER_ON (nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
 122       OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
 123       OSPF_NSM_TIMER_OFF (nbr->t_ls_req);
 124       break;
 125     case NSM_Exchange:
 126       OSPF_NSM_TIMER_ON (nbr->t_ls_upd, ospf_ls_upd_timer, nbr->v_ls_upd);
 127       if (!IS_SET_DD_MS (nbr->dd_flags))
 128         OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
 129       break;
 130     case NSM_Loading:
 131     case NSM_Full:
 132     default:
 133       OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
 134       break;
 135     }
 136 }
 137
 138 /* 10.4 of RFC2328, indicate whether an adjacency is appropriate with
 139  * the given neighbour
 140  */
 141 static int
 142 nsm_should_adj (struct ospf_neighbor *nbr)
 143 {
 144   struct ospf_interface *oi = nbr->oi;
 145
 146       /* These network types must always form adjacencies. */
 147   if (oi->type == OSPF_IFTYPE_POINTOPOINT
 148       || oi->type == OSPF_IFTYPE_POINTOMULTIPOINT
 149       || oi->type == OSPF_IFTYPE_VIRTUALLINK
 150       /* Router itself is the DRouter or the BDRouter. */
 151       || IPV4_ADDR_SAME (&oi->address->u.prefix4, &DR (oi))
 152       || IPV4_ADDR_SAME (&oi->address->u.prefix4, &BDR (oi))
 153       /* Neighboring Router is the DRouter or the BDRouter. */
 154       || IPV4_ADDR_SAME (&nbr->address.u.prefix4, &DR (oi))
 155       || IPV4_ADDR_SAME (&nbr->address.u.prefix4, &BDR (oi)))
 156     return 1;
 157
 158   return 0;
 159 }
 160
 161 /* OSPF NSM functions. */
 162 static int
 163 nsm_packet_received (struct ospf_neighbor *nbr)
 164 {
 165   /* Start or Restart Inactivity Timer. */
 166   OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
 167
 168   OSPF_NSM_TIMER_ON (nbr->t_inactivity, ospf_inactivity_timer,
 169                      nbr->v_inactivity);
 170
 171   if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma)
 172     OSPF_POLL_TIMER_OFF (nbr->nbr_nbma->t_poll);
 173
 174   /* Send proactive ARP requests */
 175   if (nbr->state < NSM_Exchange)
 176       ospf_proactively_arp (nbr);
 177
 178   return 0;
 179 }
 180
 181 static int
 182 nsm_start (struct ospf_neighbor *nbr)
 183 {
 184   if (nbr->nbr_nbma)
 185       OSPF_POLL_TIMER_OFF (nbr->nbr_nbma->t_poll);
 186
 187   OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
 188
 189   OSPF_NSM_TIMER_ON (nbr->t_inactivity, ospf_inactivity_timer,
 190                      nbr->v_inactivity);
 191
 192   /* Send proactive ARP requests */
 193   ospf_proactively_arp (nbr);
 194
 195   return 0;
 196 }
 197
 198 static int
 199 nsm_twoway_received (struct ospf_neighbor *nbr)
 200 {
 201   int adj = nsm_should_adj (nbr);
 202
 203   /* Send proactive ARP requests */
 204   if (adj)
 205      ospf_proactively_arp (nbr);
 206
 207   return (adj ? NSM_ExStart : NSM_TwoWay);
 208 }
 209
 210 int
 211 ospf_db_summary_count (struct ospf_neighbor *nbr)
 212 {
 213   return ospf_lsdb_count_all (&nbr->db_sum);
 214 }
 215
 216 int
 217 ospf_db_summary_isempty (struct ospf_neighbor *nbr)
 218 {
 219   return ospf_lsdb_isempty (&nbr->db_sum);
 220 }
 221
 222 static int
 223 ospf_db_summary_add (struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
 224 {
 225   switch (lsa->data->type)
 226     {
 227     case OSPF_OPAQUE_LINK_LSA:
 228       /* Exclude type-9 LSAs that does not have the same "oi" with "nbr". */
 229       if (nbr->oi && ospf_if_exists (lsa->oi) != nbr->oi)
 230           return 0;
 231       break;
 232     case OSPF_OPAQUE_AREA_LSA:
 233       /*
 234        * It is assured by the caller function "nsm_negotiation_done()"
 235        * that every given LSA belongs to the same area with "nbr".
 236        */
 237       break;
 238     case OSPF_OPAQUE_AS_LSA:
 239     default:
 240       break;
 241     }
 242
 243   /* Stay away from any Local Translated Type-7 LSAs */
 244   if (CHECK_FLAG (lsa->flags, OSPF_LSA_LOCAL_XLT))
 245     return 0;
 246
 247   if (IS_LSA_MAXAGE (lsa))
 248     ospf_ls_retransmit_add (nbr, lsa);
 249   else
 250     ospf_lsdb_add (&nbr->db_sum, lsa);
 251
 252   return 0;
 253 }
 254
 255 void
 256 ospf_db_summary_clear (struct ospf_neighbor *nbr)
 257 {
 258   struct ospf_lsdb *lsdb;
 259   int i;
 260
 261   lsdb = &nbr->db_sum;
 262   for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++)
 263     {
 264       struct route_table *table = lsdb->type[i].db;
 265       struct route_node *rn;
 266
 267       for (rn = route_top (table); rn; rn = route_next (rn))
 268         if (rn->info)
 269           ospf_lsdb_delete (&nbr->db_sum, rn->info);
 270     }
 271 }
 272
 273
 274
 275 /* The area link state database consists of the router-LSAs,
 276    network-LSAs and summary-LSAs contained in the area structure,
 277    along with the AS-external-LSAs contained in the global structure.
 278    AS-external-LSAs are omitted from a virtual neighbor's Database
 279    summary list.  AS-external-LSAs are omitted from the Database
 280    summary list if the area has been configured as a stub. */
 281 static int
 282 nsm_negotiation_done (struct ospf_neighbor *nbr)
 283 {
 284   struct ospf_area *area = nbr->oi->area;
 285   struct ospf_lsa *lsa;
 286   struct route_node *rn;
 287
 288   /* Send proactive ARP requests */
 289   ospf_proactively_arp (nbr);
 290
 291   LSDB_LOOP (ROUTER_LSDB (area), rn, lsa)
 292     ospf_db_summary_add (nbr, lsa);
 293   LSDB_LOOP (NETWORK_LSDB (area), rn, lsa)
 294     ospf_db_summary_add (nbr, lsa);
 295   LSDB_LOOP (SUMMARY_LSDB (area), rn, lsa)
 296     ospf_db_summary_add (nbr, lsa);
 297   LSDB_LOOP (ASBR_SUMMARY_LSDB (area), rn, lsa)
 298     ospf_db_summary_add (nbr, lsa);
 299
 300   /* Process only if the neighbor is opaque capable. */
 301   if (CHECK_FLAG (nbr->options, OSPF_OPTION_O))
 302     {
 303       LSDB_LOOP (OPAQUE_LINK_LSDB (area), rn, lsa)
 304         ospf_db_summary_add (nbr, lsa);
 305       LSDB_LOOP (OPAQUE_AREA_LSDB (area), rn, lsa)
 306         ospf_db_summary_add (nbr, lsa);
 307     }
 308
 309   if (CHECK_FLAG (nbr->options, OSPF_OPTION_NP))
 310     {
 311       LSDB_LOOP (NSSA_LSDB (area), rn, lsa)
 312         ospf_db_summary_add (nbr, lsa);
 313     }
 314
 315   if (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 316       && area->external_routing == OSPF_AREA_DEFAULT)
 317     LSDB_LOOP (EXTERNAL_LSDB (nbr->oi->ospf), rn, lsa)
 318       ospf_db_summary_add (nbr, lsa);
 319
 320   if (CHECK_FLAG (nbr->options, OSPF_OPTION_O)
 321       && (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 322           && area->external_routing == OSPF_AREA_DEFAULT))
 323     LSDB_LOOP (OPAQUE_AS_LSDB (nbr->oi->ospf), rn, lsa)
 324       ospf_db_summary_add (nbr, lsa);
 325
 326   return 0;
 327 }
 328
 329 static int
 330 nsm_exchange_done (struct ospf_neighbor *nbr)
 331 {
 332   if (ospf_ls_request_isempty (nbr))
 333     return NSM_Full;
 334
 335   /* Send Link State Request. */
 336   if (nbr->t_ls_req == NULL)
 337     ospf_ls_req_send (nbr);
 338
 339   return NSM_Loading;
 340 }
 341
 342 static int
 343 nsm_adj_ok (struct ospf_neighbor *nbr)
 344 {
 345   int next_state = nbr->state;
 346   int adj = nsm_should_adj (nbr);
 347
 348   if (nbr->state == NSM_TwoWay && adj == 1)
 349     {
 350       next_state = NSM_ExStart;
 351
 352       /* Send proactive ARP requests */
 353       ospf_proactively_arp (nbr);
 354     }
 355   else if (nbr->state >= NSM_ExStart && adj == 0)
 356     next_state = NSM_TwoWay;
 357
 358   return next_state;
 359 }
 360
 361 /* Clear adjacency related state for a neighbour, intended where nbr
 362  * transitions from > ExStart (i.e. a Full or forming adjacency)
 363  * to <= ExStart.
 364  */
 365 static void
 366 nsm_clear_adj (struct ospf_neighbor *nbr)
 367 {
 368   /* Clear Database Summary list. */
 369   if (!ospf_db_summary_isempty (nbr))
 370     ospf_db_summary_clear (nbr);
 371
 372   /* Clear Link State Request list. */
 373   if (!ospf_ls_request_isempty (nbr))
 374     ospf_ls_request_delete_all (nbr);
 375
 376   /* Clear Link State Retransmission list. */
 377   if (!ospf_ls_retransmit_isempty (nbr))
 378     ospf_ls_retransmit_clear (nbr);
 379
 380   if (CHECK_FLAG (nbr->options, OSPF_OPTION_O))
 381     UNSET_FLAG (nbr->options, OSPF_OPTION_O);
 382 }
 383
 384 static int
 385 nsm_kill_nbr (struct ospf_neighbor *nbr)
 386 {
 387   /* killing nbr_self is invalid */
 388   if (nbr == nbr->oi->nbr_self)
 389     {
 390       assert (nbr != nbr->oi->nbr_self);
 391       return 0;
 392     }
 393
 394   if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma != NULL)
 395     {
 396       struct ospf_nbr_nbma *nbr_nbma = nbr->nbr_nbma;
 397
 398       nbr_nbma->nbr = NULL;
 399       nbr_nbma->state_change = nbr->state_change;
 400
 401       nbr->nbr_nbma = NULL;
 402
 403       OSPF_POLL_TIMER_ON (nbr_nbma->t_poll, ospf_poll_timer,
 404                           nbr_nbma->v_poll);
 405
 406       if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
 407         zlog_debug ("NSM[%s:%s]: Down (PollIntervalTimer scheduled)",
 408                    IF_NAME (nbr->oi), inet_ntoa (nbr->address.u.prefix4));
 409     }
 410
 411   return 0;
 412 }
 413
 414 /* Neighbor State Machine */
 415 struct {
 416   int (*func) (struct ospf_neighbor *);
 417   int next_state;
 418 } NSM [OSPF_NSM_STATE_MAX][OSPF_NSM_EVENT_MAX] =
 419 {
 420   {
 421     /* DependUpon: dummy state. */
 422     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 423     { NULL,                    NSM_DependUpon }, /* PacketReceived    */
 424     { NULL,                    NSM_DependUpon }, /* Start             */
 425     { NULL,                    NSM_DependUpon }, /* 2-WayReceived     */
 426     { NULL,                    NSM_DependUpon }, /* NegotiationDone   */
 427     { NULL,                    NSM_DependUpon }, /* ExchangeDone      */
 428     { NULL,                    NSM_DependUpon }, /* BadLSReq          */
 429     { NULL,                    NSM_DependUpon }, /* LoadingDone       */
 430     { NULL,                    NSM_DependUpon }, /* AdjOK?            */
 431     { NULL,                    NSM_DependUpon }, /* SeqNumberMismatch */
 432     { NULL,                    NSM_DependUpon }, /* 1-WayReceived     */
 433     { NULL,                    NSM_DependUpon }, /* KillNbr           */
 434     { NULL,                    NSM_DependUpon }, /* InactivityTimer   */
 435     { NULL,                    NSM_DependUpon }, /* LLDown            */
 436   },
 437   {
 438     /* Deleted: dummy state. */
 439     { NULL,                    NSM_Deleted    }, /* NoEvent           */
 440     { NULL,                    NSM_Deleted    }, /* PacketReceived    */
 441     { NULL,                    NSM_Deleted    }, /* Start             */
 442     { NULL,                    NSM_Deleted    }, /* 2-WayReceived     */
 443     { NULL,                    NSM_Deleted    }, /* NegotiationDone   */
 444     { NULL,                    NSM_Deleted    }, /* ExchangeDone      */
 445     { NULL,                    NSM_Deleted    }, /* BadLSReq          */
 446     { NULL,                    NSM_Deleted    }, /* LoadingDone       */
 447     { NULL,                    NSM_Deleted    }, /* AdjOK?            */
 448     { NULL,                    NSM_Deleted    }, /* SeqNumberMismatch */
 449     { NULL,                    NSM_Deleted    }, /* 1-WayReceived     */
 450     { NULL,                    NSM_Deleted    }, /* KillNbr           */
 451     { NULL,                    NSM_Deleted    }, /* InactivityTimer   */
 452     { NULL,                    NSM_Deleted    }, /* LLDown            */
 453   },
 454   {
 455     /* Down: */
 456     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 457     { nsm_packet_received,     NSM_Init       }, /* PacketReceived    */
 458     { nsm_start,               NSM_Attempt    }, /* Start             */
 459     { NULL,                    NSM_Down       }, /* 2-WayReceived     */
 460     { NULL,                    NSM_Down       }, /* NegotiationDone   */
 461     { NULL,                    NSM_Down       }, /* ExchangeDone      */
 462     { NULL,                    NSM_Down       }, /* BadLSReq          */
 463     { NULL,                    NSM_Down       }, /* LoadingDone       */
 464     { NULL,                    NSM_Down       }, /* AdjOK?            */
 465     { NULL,                    NSM_Down       }, /* SeqNumberMismatch */
 466     { NULL,                    NSM_Down       }, /* 1-WayReceived     */
 467     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 468     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 469     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 470   },
 471   {
 472     /* Attempt: */
 473     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 474     { nsm_packet_received,     NSM_Init       }, /* PacketReceived    */
 475     { NULL,                    NSM_Attempt    }, /* Start             */
 476     { NULL,                    NSM_Attempt    }, /* 2-WayReceived     */
 477     { NULL,                    NSM_Attempt    }, /* NegotiationDone   */
 478     { NULL,                    NSM_Attempt    }, /* ExchangeDone      */
 479     { NULL,                    NSM_Attempt    }, /* BadLSReq          */
 480     { NULL,                    NSM_Attempt    }, /* LoadingDone       */
 481     { NULL,                    NSM_Attempt    }, /* AdjOK?            */
 482     { NULL,                    NSM_Attempt    }, /* SeqNumberMismatch */
 483     { NULL,                    NSM_Attempt    }, /* 1-WayReceived     */
 484     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 485     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 486     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 487   },
 488   {
 489     /* Init: */
 490     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 491     { nsm_packet_received,     NSM_Init      }, /* PacketReceived    */
 492     { NULL,                    NSM_Init       }, /* Start             */
 493     { nsm_twoway_received,     NSM_DependUpon }, /* 2-WayReceived     */
 494     { NULL,                    NSM_Init       }, /* NegotiationDone   */
 495     { NULL,                    NSM_Init       }, /* ExchangeDone      */
 496     { NULL,                    NSM_Init       }, /* BadLSReq          */
 497     { NULL,                    NSM_Init       }, /* LoadingDone       */
 498     { NULL,                    NSM_Init       }, /* AdjOK?            */
 499     { NULL,                    NSM_Init       }, /* SeqNumberMismatch */
 500     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 501     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 502     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 503     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 504   },
 505   {
 506     /* 2-Way: */
 507     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 508     { nsm_packet_received,     NSM_TwoWay     }, /* HelloReceived     */
 509     { NULL,                    NSM_TwoWay     }, /* Start             */
 510     { NULL,                    NSM_TwoWay     }, /* 2-WayReceived     */
 511     { NULL,                    NSM_TwoWay     }, /* NegotiationDone   */
 512     { NULL,                    NSM_TwoWay     }, /* ExchangeDone      */
 513     { NULL,                    NSM_TwoWay     }, /* BadLSReq          */
 514     { NULL,                    NSM_TwoWay     }, /* LoadingDone       */
 515     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 516     { NULL,                    NSM_TwoWay     }, /* SeqNumberMismatch */
 517     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 518     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 519     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 520     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 521   },
 522   {
 523     /* ExStart: */
 524     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 525     { nsm_packet_received,     NSM_ExStart    }, /* PacaketReceived   */
 526     { NULL,                    NSM_ExStart    }, /* Start             */
 527     { NULL,                    NSM_ExStart    }, /* 2-WayReceived     */
 528     { nsm_negotiation_done,    NSM_Exchange   }, /* NegotiationDone   */
 529     { NULL,                    NSM_ExStart    }, /* ExchangeDone      */
 530     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 531     { NULL,                    NSM_ExStart    }, /* LoadingDone       */
 532     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 533     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 534     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 535     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 536     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 537     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 538   },
 539   {
 540     /* Exchange: */
 541     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 542     { nsm_packet_received,     NSM_Exchange   }, /* PacketReceived    */
 543     { NULL,                    NSM_Exchange   }, /* Start             */
 544     { NULL,                    NSM_Exchange   }, /* 2-WayReceived     */
 545     { NULL,                    NSM_Exchange   }, /* NegotiationDone   */
 546     { nsm_exchange_done,       NSM_DependUpon }, /* ExchangeDone      */
 547     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 548     { NULL,                    NSM_Exchange   }, /* LoadingDone       */
 549     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 550     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 551     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 552     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 553     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 554     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 555   },
 556   {
 557     /* Loading: */
 558     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 559     { nsm_packet_received,     NSM_Loading    }, /* PacketReceived    */
 560     { NULL,                    NSM_Loading    }, /* Start             */
 561     { NULL,                    NSM_Loading    }, /* 2-WayReceived     */
 562     { NULL,                    NSM_Loading    }, /* NegotiationDone   */
 563     { NULL,                    NSM_Loading    }, /* ExchangeDone      */
 564     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 565     { NULL,                    NSM_Full       }, /* LoadingDone       */
 566     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 567     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 568     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 569     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 570     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 571     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 572   },
 573   { /* Full: */
 574     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 575     { nsm_packet_received,     NSM_Full       }, /* PacketReceived    */
 576     { NULL,                    NSM_Full       }, /* Start             */
 577     { NULL,                    NSM_Full       }, /* 2-WayReceived     */
 578     { NULL,                    NSM_Full       }, /* NegotiationDone   */
 579     { NULL,                    NSM_Full       }, /* ExchangeDone      */
 580     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 581     { NULL,                    NSM_Full       }, /* LoadingDone       */
 582     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 583     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 584     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 585     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 586     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 587     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 588   },
 589 };
 590
 591 static const char *ospf_nsm_event_str[] =
 592 {
 593   "NoEvent",
 594   "PacketReceived",
 595   "Start",
 596   "2-WayReceived",
 597   "NegotiationDone",
 598   "ExchangeDone",
 599   "BadLSReq",
 600   "LoadingDone",
 601   "AdjOK?",
 602   "SeqNumberMismatch",
 603   "1-WayReceived",
 604   "KillNbr",
 605   "InactivityTimer",
 606   "LLDown",
 607 };
 608
 609 static void
 610 nsm_notice_state_change (struct ospf_neighbor *nbr, int next_state, int event)
 611 {
 612   /* Logging change of status. */
 613   if (IS_DEBUG_OSPF (nsm, NSM_STATUS))
 614     zlog_debug ("NSM[%s:%s]: State change %s -> %s (%s)",
 615                IF_NAME (nbr->oi), inet_ntoa (nbr->router_id),
 616                LOOKUP (ospf_nsm_state_msg, nbr->state),
 617                LOOKUP (ospf_nsm_state_msg, next_state),
 618                ospf_nsm_event_str [event]);
 619
 620   /* Optionally notify about adjacency changes */
 621   if (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_CHANGES) &&
 622       (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL) ||
 623        (next_state == NSM_Full) || (next_state < nbr->state)))
 624     zlog_notice("AdjChg: Nbr %s on %s: %s -> %s (%s)",
 625                 inet_ntoa (nbr->router_id), IF_NAME (nbr->oi),
 626                 LOOKUP (ospf_nsm_state_msg, nbr->state),
 627                 LOOKUP (ospf_nsm_state_msg, next_state),
 628                 ospf_nsm_event_str [event]);
 629
 630   /* Advance in NSM */
 631   if (next_state > nbr->state)
 632     nbr->ts_last_progress = recent_relative_time ();
 633   else /* regression in NSM */
 634     {
 635       nbr->ts_last_regress = recent_relative_time ();
 636       nbr->last_regress_str = ospf_nsm_event_str [event];
 637     }
 638
 639 }
 640
 641 static void
 642 nsm_change_state (struct ospf_neighbor *nbr, int state)
 643 {
 644   struct ospf_interface *oi = nbr->oi;
 645   struct ospf_area *vl_area = NULL;
 646   u_char old_state;
 647   int x;
 648   int force = 1;
 649
 650   /* Preserve old status. */
 651   old_state = nbr->state;
 652
 653   /* Change to new status. */
 654   nbr->state = state;
 655
 656   /* Statistics. */
 657   nbr->state_change++;
 658
 659   if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
 660     vl_area = ospf_area_lookup_by_area_id (oi->ospf, oi->vl_data->vl_area_id);
 661
 662   /* Generate NeighborChange ISM event.
 663    *
 664    * In response to NeighborChange, DR election is rerun. The information
 665    * from the election process is required by the router-lsa construction.
 666    *
 667    * Therefore, trigger the event prior to refreshing the LSAs. */
 668   switch (oi->state) {
 669   case ISM_DROther:
 670   case ISM_Backup:
 671   case ISM_DR:
 672     if ((old_state < NSM_TwoWay && state >= NSM_TwoWay) ||
 673         (old_state >= NSM_TwoWay && state < NSM_TwoWay))
 674       OSPF_ISM_EVENT_EXECUTE (oi, ISM_NeighborChange);
 675     break;
 676   default:
 677     /* ISM_PointToPoint -> ISM_Down, ISM_Loopback -> ISM_Down, etc. */
 678     break;
 679   }
 680
 681   /* One of the neighboring routers changes to/from the FULL state. */
 682   if ((old_state != NSM_Full && state == NSM_Full) ||
 683       (old_state == NSM_Full && state != NSM_Full))
 684     {
 685       if (state == NSM_Full)
 686         {
 687           oi->full_nbrs++;
 688           oi->area->full_nbrs++;
 689
 690           ospf_check_abr_status (oi->ospf);
 691
 692           if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 693             if (++vl_area->full_vls == 1)
 694               ospf_schedule_abr_task (oi->ospf);
 695
 696           /* kevinm: refresh any redistributions */
 697           for (x = ZEBRA_ROUTE_SYSTEM; x < ZEBRA_ROUTE_MAX; x++)
 698             {
 699               struct list *red_list;
 700               struct listnode *node;
 701               struct ospf_redist *red;
 702
 703               if (x == ZEBRA_ROUTE_OSPF6)
 704                 continue;
 705
 706               red_list = oi->ospf->redist[x];
 707               if (!red_list)
 708                 continue;
 709
 710               for (ALL_LIST_ELEMENTS_RO(red_list, node, red))
 711                 ospf_external_lsa_refresh_type (oi->ospf, x, red->instance, force);
 712             }
 713           /* XXX: Clearly some thing is wrong with refresh of external LSAs
 714            * this added to hack around defaults not refreshing after a timer
 715            * jump.
 716            */
 717           ospf_external_lsa_refresh_default (oi->ospf);
 718         }
 719       else
 720         {
 721           oi->full_nbrs--;
 722           oi->area->full_nbrs--;
 723
 724           ospf_check_abr_status (oi->ospf);
 725
 726           if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 727             if (vl_area->full_vls > 0)
 728               if (--vl_area->full_vls == 0)
 729                 ospf_schedule_abr_task (oi->ospf);
 730         }
 731
 732       zlog_info ("nsm_change_state(%s, %s -> %s): "
 733                  "scheduling new router-LSA origination",
 734                  inet_ntoa (nbr->router_id),
 735                  LOOKUP(ospf_nsm_state_msg, old_state),
 736                  LOOKUP(ospf_nsm_state_msg, state));
 737
 738       ospf_router_lsa_update_area (oi->area);
 739
 740       if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
 741         {
 742           struct ospf_area *vl_area =
 743             ospf_area_lookup_by_area_id (oi->ospf, oi->vl_data->vl_area_id);
 744
 745           if (vl_area)
 746             ospf_router_lsa_update_area (vl_area);
 747         }
 748
 749       /* Originate network-LSA. */
 750       if (oi->state == ISM_DR)
 751         {
 752           if (oi->network_lsa_self && oi->full_nbrs == 0)
 753             {
 754               ospf_lsa_flush_area (oi->network_lsa_self, oi->area);
 755               ospf_lsa_unlock (&oi->network_lsa_self);
 756               oi->network_lsa_self = NULL;
 757             }
 758           else
 759             ospf_network_lsa_update (oi);
 760         }
 761     }
 762
 763   ospf_opaque_nsm_change (nbr, old_state);
 764
 765   /* State changes from > ExStart to <= ExStart should clear any Exchange
 766    * or Full/LSA Update related lists and state.
 767    * Potential causal events: BadLSReq, SeqNumberMismatch, AdjOK?
 768    */
 769   if ((old_state > NSM_ExStart) && (state <= NSM_ExStart))
 770     nsm_clear_adj (nbr);
 771
 772   /* Start DD exchange protocol */
 773   if (state == NSM_ExStart)
 774     {
 775       if (nbr->dd_seqnum == 0)
 776         nbr->dd_seqnum = (uint32_t)random ();
 777       else
 778         nbr->dd_seqnum++;
 779
 780       nbr->dd_flags = OSPF_DD_FLAG_I|OSPF_DD_FLAG_M|OSPF_DD_FLAG_MS;
 781       ospf_db_desc_send (nbr);
 782     }
 783
 784   /* clear cryptographic sequence number */
 785   if (state == NSM_Down)
 786     nbr->crypt_seqnum = 0;
 787
 788   ospf_bfd_trigger_event(nbr, old_state, state);
 789
 790   /* Preserve old status? */
 791 }
 792
 793 /* Execute NSM event process. */
 794 int
 795 ospf_nsm_event (struct thread *thread)
 796 {
 797   int event;
 798   int next_state;
 799   struct ospf_neighbor *nbr;
 800
 801   nbr = THREAD_ARG (thread);
 802   event = THREAD_VAL (thread);
 803
 804   if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
 805     zlog_debug ("NSM[%s:%s]: %s (%s)", IF_NAME (nbr->oi),
 806                inet_ntoa (nbr->router_id),
 807                LOOKUP (ospf_nsm_state_msg, nbr->state),
 808                ospf_nsm_event_str [event]);
 809
 810   next_state = NSM [nbr->state][event].next_state;
 811
 812   /* Call function. */
 813   if (NSM [nbr->state][event].func != NULL)
 814     {
 815       int func_state = (*(NSM [nbr->state][event].func))(nbr);
 816
 817       if (NSM [nbr->state][event].next_state == NSM_DependUpon)
 818         next_state = func_state;
 819       else if (func_state)
 820         {
 821           /* There's a mismatch between the FSM tables and what an FSM
 822            * action/state-change function returned. State changes which
 823            * do not have conditional/DependUpon next-states should not
 824            * try set next_state.
 825            */
 826           zlog_warn ("NSM[%s:%s]: %s (%s): "
 827                      "Warning: action tried to change next_state to %s",
 828                      IF_NAME (nbr->oi), inet_ntoa (nbr->router_id),
 829                      LOOKUP (ospf_nsm_state_msg, nbr->state),
 830                      ospf_nsm_event_str [event],
 831                      LOOKUP (ospf_nsm_state_msg, func_state));
 832         }
 833     }
 834
 835   assert (next_state != NSM_DependUpon);
 836
 837   /* If state is changed. */
 838   if (next_state != nbr->state)
 839     {
 840       nsm_notice_state_change (nbr, next_state, event);
 841 #ifdef HAVE_SNMP
 842       int send_trap_virt = 0;
 843       int send_trap = 0;
 844       /* Terminal state or regression */
 845       if ((next_state == NSM_Full)
 846               || (next_state == NSM_TwoWay)
 847               || (next_state < nbr->state))
 848       {
 849           /* ospfVirtNbrStateChange */
 850           if (nbr->oi->type == OSPF_IFTYPE_VIRTUALLINK)
 851               send_trap_virt = 1;
 852           /* ospfNbrStateChange trap  */
 853           else
 854               /* To/From FULL, only managed by DR */
 855               if (((next_state != NSM_Full) && (nbr->state != NSM_Full))
 856                       || (nbr->oi->state == ISM_DR))
 857                   send_trap = 1;
 858       }
 859 #endif
 860       nsm_change_state (nbr, next_state);
 861
 862 #ifdef HAVE_SNMP
 863       if (send_trap_virt) {
 864           ospfTrapVirtNbrStateChange(nbr);
 865       } else if (send_trap) {
 866           ospfTrapNbrStateChange(nbr);
 867       }
 868 #endif
 869     }
 870
 871   /* Make sure timer is set. */
 872   nsm_timer_set (nbr);
 873
 874   /* When event is NSM_KillNbr, InactivityTimer or LLDown, the neighbor
 875    * is deleted.
 876    *
 877    * Rather than encode knowledge here of which events lead to NBR
 878    * delete, we take our cue from the NSM table, via the dummy
 879    * 'Deleted' neighbour state.
 880    */
 881   if (nbr->state == NSM_Deleted)
 882     ospf_nbr_delete (nbr);
 883
 884   return 0;
 885 }
 886
 887 /* Check loading state. */
 888 void
 889 ospf_check_nbr_loading (struct ospf_neighbor *nbr)
 890 {
 891   if (nbr->state == NSM_Loading)
 892     {
 893       if (ospf_ls_request_isempty (nbr))
 894         OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_LoadingDone);
 895       else if (nbr->ls_req_last == NULL)
 896         ospf_ls_req_event (nbr);
 897     }
 898 }