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 along
  19  * with this program; see the file COPYING; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <zebra.h>
  24
  25 #include "thread.h"
  26 #include "memory.h"
  27 #include "hash.h"
  28 #include "linklist.h"
  29 #include "prefix.h"
  30 #include "if.h"
  31 #include "table.h"
  32 #include "stream.h"
  33 #include "table.h"
  34 #include "log.h"
  35 #include "command.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_bfd.h"
  51
  52 DEFINE_HOOK(ospf_nsm_change,
  53                 (struct ospf_neighbor *on, int state, int oldstate),
  54                 (on, state, oldstate))
  55
  56 static void nsm_clear_adj (struct ospf_neighbor *);
  57
  58 /* OSPF NSM Timer functions. */
  59 static int
  60 ospf_inactivity_timer (struct thread *thread)
  61 {
  62   struct ospf_neighbor *nbr;
  63
  64   nbr = THREAD_ARG (thread);
  65   nbr->t_inactivity = NULL;
  66
  67   if (IS_DEBUG_OSPF (nsm, NSM_TIMERS))
  68     zlog_debug("NSM[%s:%s]: Timer (Inactivity timer expire)",
  69                IF_NAME(nbr->oi), inet_ntoa(nbr->router_id));
  70
  71   OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_InactivityTimer);
  72
  73   return 0;
  74 }
  75
  76 static int
  77 ospf_db_desc_timer (struct thread *thread)
  78 {
  79   struct ospf_neighbor *nbr;
  80
  81   nbr = THREAD_ARG (thread);
  82   nbr->t_db_desc = NULL;
  83
  84   if (IS_DEBUG_OSPF (nsm, NSM_TIMERS))
  85     zlog_debug("NSM[%s:%s]: Timer (DD Retransmit timer expire)",
  86                IF_NAME(nbr->oi), inet_ntoa(nbr->src));
  87
  88   /* resent last send DD packet. */
  89   assert (nbr->last_send);
  90   ospf_db_desc_resend (nbr);
  91
  92   /* DD Retransmit timer set. */
  93   OSPF_NSM_TIMER_ON (nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
  94
  95   return 0;
  96 }
  97
  98 /* Hook function called after ospf NSM event is occured.
  99  *
 100  * Set/clear any timers whose condition is implicit to the neighbour
 101  * state. There may be other timers which are set/unset according to other
 102  * state.
 103  *
 104  * We rely on this function to properly clear timers in lower states,
 105  * particularly before deleting a neighbour.
 106  */
 107 static void
 108 nsm_timer_set (struct ospf_neighbor *nbr)
 109 {
 110   switch (nbr->state)
 111     {
 112     case NSM_Deleted:
 113     case NSM_Down:
 114       OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
 115       OSPF_NSM_TIMER_OFF (nbr->t_hello_reply);
 116     case NSM_Attempt:
 117     case NSM_Init:
 118     case NSM_TwoWay:
 119       OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
 120       OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
 121       OSPF_NSM_TIMER_OFF (nbr->t_ls_req);
 122       break;
 123     case NSM_ExStart:
 124       OSPF_NSM_TIMER_ON (nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
 125       OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
 126       OSPF_NSM_TIMER_OFF (nbr->t_ls_req);
 127       break;
 128     case NSM_Exchange:
 129       OSPF_NSM_TIMER_ON (nbr->t_ls_upd, ospf_ls_upd_timer, nbr->v_ls_upd);
 130       if (!IS_SET_DD_MS (nbr->dd_flags))
 131         OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
 132       break;
 133     case NSM_Loading:
 134     case NSM_Full:
 135     default:
 136       OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
 137       break;
 138     }
 139 }
 140
 141 /* 10.4 of RFC2328, indicate whether an adjacency is appropriate with
 142  * the given neighbour
 143  */
 144 static int
 145 nsm_should_adj (struct ospf_neighbor *nbr)
 146 {
 147   struct ospf_interface *oi = nbr->oi;
 148
 149       /* These network types must always form adjacencies. */
 150   if (oi->type == OSPF_IFTYPE_POINTOPOINT
 151       || oi->type == OSPF_IFTYPE_POINTOMULTIPOINT
 152       || oi->type == OSPF_IFTYPE_VIRTUALLINK
 153       /* Router itself is the DRouter or the BDRouter. */
 154       || IPV4_ADDR_SAME (&oi->address->u.prefix4, &DR (oi))
 155       || IPV4_ADDR_SAME (&oi->address->u.prefix4, &BDR (oi))
 156       /* Neighboring Router is the DRouter or the BDRouter. */
 157       || IPV4_ADDR_SAME (&nbr->address.u.prefix4, &DR (oi))
 158       || IPV4_ADDR_SAME (&nbr->address.u.prefix4, &BDR (oi)))
 159     return 1;
 160
 161   return 0;
 162 }
 163
 164 /* OSPF NSM functions. */
 165 static int
 166 nsm_packet_received (struct ospf_neighbor *nbr)
 167 {
 168   /* Start or Restart Inactivity Timer. */
 169   OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
 170
 171   OSPF_NSM_TIMER_ON (nbr->t_inactivity, ospf_inactivity_timer,
 172                      nbr->v_inactivity);
 173
 174   if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma)
 175     OSPF_POLL_TIMER_OFF (nbr->nbr_nbma->t_poll);
 176
 177   /* Send proactive ARP requests */
 178   if (nbr->state < NSM_Exchange)
 179       ospf_proactively_arp (nbr);
 180
 181   return 0;
 182 }
 183
 184 static int
 185 nsm_start (struct ospf_neighbor *nbr)
 186 {
 187   if (nbr->nbr_nbma)
 188       OSPF_POLL_TIMER_OFF (nbr->nbr_nbma->t_poll);
 189
 190   OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
 191
 192   OSPF_NSM_TIMER_ON (nbr->t_inactivity, ospf_inactivity_timer,
 193                      nbr->v_inactivity);
 194
 195   /* Send proactive ARP requests */
 196   ospf_proactively_arp (nbr);
 197
 198   return 0;
 199 }
 200
 201 static int
 202 nsm_twoway_received (struct ospf_neighbor *nbr)
 203 {
 204   int adj = nsm_should_adj (nbr);
 205
 206   /* Send proactive ARP requests */
 207   if (adj)
 208      ospf_proactively_arp (nbr);
 209
 210   return (adj ? NSM_ExStart : NSM_TwoWay);
 211 }
 212
 213 int
 214 ospf_db_summary_count (struct ospf_neighbor *nbr)
 215 {
 216   return ospf_lsdb_count_all (&nbr->db_sum);
 217 }
 218
 219 int
 220 ospf_db_summary_isempty (struct ospf_neighbor *nbr)
 221 {
 222   return ospf_lsdb_isempty (&nbr->db_sum);
 223 }
 224
 225 static int
 226 ospf_db_summary_add (struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
 227 {
 228   switch (lsa->data->type)
 229     {
 230     case OSPF_OPAQUE_LINK_LSA:
 231       /* Exclude type-9 LSAs that does not have the same "oi" with "nbr". */
 232       if (nbr->oi && ospf_if_exists (lsa->oi) != nbr->oi)
 233           return 0;
 234       break;
 235     case OSPF_OPAQUE_AREA_LSA:
 236       /*
 237        * It is assured by the caller function "nsm_negotiation_done()"
 238        * that every given LSA belongs to the same area with "nbr".
 239        */
 240       break;
 241     case OSPF_OPAQUE_AS_LSA:
 242     default:
 243       break;
 244     }
 245
 246   /* Stay away from any Local Translated Type-7 LSAs */
 247   if (CHECK_FLAG (lsa->flags, OSPF_LSA_LOCAL_XLT))
 248     return 0;
 249
 250   if (IS_LSA_MAXAGE (lsa))
 251     ospf_ls_retransmit_add (nbr, lsa);
 252   else
 253     ospf_lsdb_add (&nbr->db_sum, lsa);
 254
 255   return 0;
 256 }
 257
 258 void
 259 ospf_db_summary_clear (struct ospf_neighbor *nbr)
 260 {
 261   struct ospf_lsdb *lsdb;
 262   int i;
 263
 264   lsdb = &nbr->db_sum;
 265   for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++)
 266     {
 267       struct route_table *table = lsdb->type[i].db;
 268       struct route_node *rn;
 269
 270       for (rn = route_top (table); rn; rn = route_next (rn))
 271         if (rn->info)
 272           ospf_lsdb_delete (&nbr->db_sum, rn->info);
 273     }
 274 }
 275
 276
 277
 278 /* The area link state database consists of the router-LSAs,
 279    network-LSAs and summary-LSAs contained in the area structure,
 280    along with the AS-external-LSAs contained in the global structure.
 281    AS-external-LSAs are omitted from a virtual neighbor's Database
 282    summary list.  AS-external-LSAs are omitted from the Database
 283    summary list if the area has been configured as a stub. */
 284 static int
 285 nsm_negotiation_done (struct ospf_neighbor *nbr)
 286 {
 287   struct ospf_area *area = nbr->oi->area;
 288   struct ospf_lsa *lsa;
 289   struct route_node *rn;
 290
 291   /* Send proactive ARP requests */
 292   ospf_proactively_arp (nbr);
 293
 294   LSDB_LOOP (ROUTER_LSDB (area), rn, lsa)
 295     ospf_db_summary_add (nbr, lsa);
 296   LSDB_LOOP (NETWORK_LSDB (area), rn, lsa)
 297     ospf_db_summary_add (nbr, lsa);
 298   LSDB_LOOP (SUMMARY_LSDB (area), rn, lsa)
 299     ospf_db_summary_add (nbr, lsa);
 300   LSDB_LOOP (ASBR_SUMMARY_LSDB (area), rn, lsa)
 301     ospf_db_summary_add (nbr, lsa);
 302
 303   /* Process only if the neighbor is opaque capable. */
 304   if (CHECK_FLAG (nbr->options, OSPF_OPTION_O))
 305     {
 306       LSDB_LOOP (OPAQUE_LINK_LSDB (area), rn, lsa)
 307         ospf_db_summary_add (nbr, lsa);
 308       LSDB_LOOP (OPAQUE_AREA_LSDB (area), rn, lsa)
 309         ospf_db_summary_add (nbr, lsa);
 310     }
 311
 312   if (CHECK_FLAG (nbr->options, OSPF_OPTION_NP))
 313     {
 314       LSDB_LOOP (NSSA_LSDB (area), rn, lsa)
 315         ospf_db_summary_add (nbr, lsa);
 316     }
 317
 318   if (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 319       && area->external_routing == OSPF_AREA_DEFAULT)
 320     LSDB_LOOP (EXTERNAL_LSDB (nbr->oi->ospf), rn, lsa)
 321       ospf_db_summary_add (nbr, lsa);
 322
 323   if (CHECK_FLAG (nbr->options, OSPF_OPTION_O)
 324       && (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 325           && area->external_routing == OSPF_AREA_DEFAULT))
 326     LSDB_LOOP (OPAQUE_AS_LSDB (nbr->oi->ospf), rn, lsa)
 327       ospf_db_summary_add (nbr, lsa);
 328
 329   return 0;
 330 }
 331
 332 static int
 333 nsm_exchange_done (struct ospf_neighbor *nbr)
 334 {
 335   if (ospf_ls_request_isempty (nbr))
 336     return NSM_Full;
 337
 338   /* Send Link State Request. */
 339   if (nbr->t_ls_req == NULL)
 340     ospf_ls_req_send (nbr);
 341
 342   return NSM_Loading;
 343 }
 344
 345 static int
 346 nsm_adj_ok (struct ospf_neighbor *nbr)
 347 {
 348   int next_state = nbr->state;
 349   int adj = nsm_should_adj (nbr);
 350
 351   if (nbr->state == NSM_TwoWay && adj == 1)
 352     {
 353       next_state = NSM_ExStart;
 354
 355       /* Send proactive ARP requests */
 356       ospf_proactively_arp (nbr);
 357     }
 358   else if (nbr->state >= NSM_ExStart && adj == 0)
 359     next_state = NSM_TwoWay;
 360
 361   return next_state;
 362 }
 363
 364 /* Clear adjacency related state for a neighbour, intended where nbr
 365  * transitions from > ExStart (i.e. a Full or forming adjacency)
 366  * to <= ExStart.
 367  */
 368 static void
 369 nsm_clear_adj (struct ospf_neighbor *nbr)
 370 {
 371   /* Clear Database Summary list. */
 372   if (!ospf_db_summary_isempty (nbr))
 373     ospf_db_summary_clear (nbr);
 374
 375   /* Clear Link State Request list. */
 376   if (!ospf_ls_request_isempty (nbr))
 377     ospf_ls_request_delete_all (nbr);
 378
 379   /* Clear Link State Retransmission list. */
 380   if (!ospf_ls_retransmit_isempty (nbr))
 381     ospf_ls_retransmit_clear (nbr);
 382
 383   if (CHECK_FLAG (nbr->options, OSPF_OPTION_O))
 384     UNSET_FLAG (nbr->options, OSPF_OPTION_O);
 385 }
 386
 387 static int
 388 nsm_kill_nbr (struct ospf_neighbor *nbr)
 389 {
 390   /* killing nbr_self is invalid */
 391   if (nbr == nbr->oi->nbr_self)
 392     {
 393       assert (nbr != nbr->oi->nbr_self);
 394       return 0;
 395     }
 396
 397   if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma != NULL)
 398     {
 399       struct ospf_nbr_nbma *nbr_nbma = nbr->nbr_nbma;
 400
 401       nbr_nbma->nbr = NULL;
 402       nbr_nbma->state_change = nbr->state_change;
 403
 404       nbr->nbr_nbma = NULL;
 405
 406       OSPF_POLL_TIMER_ON (nbr_nbma->t_poll, ospf_poll_timer,
 407                           nbr_nbma->v_poll);
 408
 409       if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
 410         zlog_debug ("NSM[%s:%s]: Down (PollIntervalTimer scheduled)",
 411                    IF_NAME (nbr->oi), inet_ntoa (nbr->address.u.prefix4));
 412     }
 413
 414   return 0;
 415 }
 416
 417 /* Neighbor State Machine */
 418 struct {
 419   int (*func) (struct ospf_neighbor *);
 420   int next_state;
 421 } NSM [OSPF_NSM_STATE_MAX][OSPF_NSM_EVENT_MAX] =
 422 {
 423   {
 424     /* DependUpon: dummy state. */
 425     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 426     { NULL,                    NSM_DependUpon }, /* PacketReceived    */
 427     { NULL,                    NSM_DependUpon }, /* Start             */
 428     { NULL,                    NSM_DependUpon }, /* 2-WayReceived     */
 429     { NULL,                    NSM_DependUpon }, /* NegotiationDone   */
 430     { NULL,                    NSM_DependUpon }, /* ExchangeDone      */
 431     { NULL,                    NSM_DependUpon }, /* BadLSReq          */
 432     { NULL,                    NSM_DependUpon }, /* LoadingDone       */
 433     { NULL,                    NSM_DependUpon }, /* AdjOK?            */
 434     { NULL,                    NSM_DependUpon }, /* SeqNumberMismatch */
 435     { NULL,                    NSM_DependUpon }, /* 1-WayReceived     */
 436     { NULL,                    NSM_DependUpon }, /* KillNbr           */
 437     { NULL,                    NSM_DependUpon }, /* InactivityTimer   */
 438     { NULL,                    NSM_DependUpon }, /* LLDown            */
 439   },
 440   {
 441     /* Deleted: dummy state. */
 442     { NULL,                    NSM_Deleted    }, /* NoEvent           */
 443     { NULL,                    NSM_Deleted    }, /* PacketReceived    */
 444     { NULL,                    NSM_Deleted    }, /* Start             */
 445     { NULL,                    NSM_Deleted    }, /* 2-WayReceived     */
 446     { NULL,                    NSM_Deleted    }, /* NegotiationDone   */
 447     { NULL,                    NSM_Deleted    }, /* ExchangeDone      */
 448     { NULL,                    NSM_Deleted    }, /* BadLSReq          */
 449     { NULL,                    NSM_Deleted    }, /* LoadingDone       */
 450     { NULL,                    NSM_Deleted    }, /* AdjOK?            */
 451     { NULL,                    NSM_Deleted    }, /* SeqNumberMismatch */
 452     { NULL,                    NSM_Deleted    }, /* 1-WayReceived     */
 453     { NULL,                    NSM_Deleted    }, /* KillNbr           */
 454     { NULL,                    NSM_Deleted    }, /* InactivityTimer   */
 455     { NULL,                    NSM_Deleted    }, /* LLDown            */
 456   },
 457   {
 458     /* Down: */
 459     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 460     { nsm_packet_received,     NSM_Init       }, /* PacketReceived    */
 461     { nsm_start,               NSM_Attempt    }, /* Start             */
 462     { NULL,                    NSM_Down       }, /* 2-WayReceived     */
 463     { NULL,                    NSM_Down       }, /* NegotiationDone   */
 464     { NULL,                    NSM_Down       }, /* ExchangeDone      */
 465     { NULL,                    NSM_Down       }, /* BadLSReq          */
 466     { NULL,                    NSM_Down       }, /* LoadingDone       */
 467     { NULL,                    NSM_Down       }, /* AdjOK?            */
 468     { NULL,                    NSM_Down       }, /* SeqNumberMismatch */
 469     { NULL,                    NSM_Down       }, /* 1-WayReceived     */
 470     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 471     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 472     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 473   },
 474   {
 475     /* Attempt: */
 476     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 477     { nsm_packet_received,     NSM_Init       }, /* PacketReceived    */
 478     { NULL,                    NSM_Attempt    }, /* Start             */
 479     { NULL,                    NSM_Attempt    }, /* 2-WayReceived     */
 480     { NULL,                    NSM_Attempt    }, /* NegotiationDone   */
 481     { NULL,                    NSM_Attempt    }, /* ExchangeDone      */
 482     { NULL,                    NSM_Attempt    }, /* BadLSReq          */
 483     { NULL,                    NSM_Attempt    }, /* LoadingDone       */
 484     { NULL,                    NSM_Attempt    }, /* AdjOK?            */
 485     { NULL,                    NSM_Attempt    }, /* SeqNumberMismatch */
 486     { NULL,                    NSM_Attempt    }, /* 1-WayReceived     */
 487     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 488     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 489     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 490   },
 491   {
 492     /* Init: */
 493     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 494     { nsm_packet_received,     NSM_Init      }, /* PacketReceived    */
 495     { NULL,                    NSM_Init       }, /* Start             */
 496     { nsm_twoway_received,     NSM_DependUpon }, /* 2-WayReceived     */
 497     { NULL,                    NSM_Init       }, /* NegotiationDone   */
 498     { NULL,                    NSM_Init       }, /* ExchangeDone      */
 499     { NULL,                    NSM_Init       }, /* BadLSReq          */
 500     { NULL,                    NSM_Init       }, /* LoadingDone       */
 501     { NULL,                    NSM_Init       }, /* AdjOK?            */
 502     { NULL,                    NSM_Init       }, /* SeqNumberMismatch */
 503     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 504     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 505     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 506     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 507   },
 508   {
 509     /* 2-Way: */
 510     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 511     { nsm_packet_received,     NSM_TwoWay     }, /* HelloReceived     */
 512     { NULL,                    NSM_TwoWay     }, /* Start             */
 513     { NULL,                    NSM_TwoWay     }, /* 2-WayReceived     */
 514     { NULL,                    NSM_TwoWay     }, /* NegotiationDone   */
 515     { NULL,                    NSM_TwoWay     }, /* ExchangeDone      */
 516     { NULL,                    NSM_TwoWay     }, /* BadLSReq          */
 517     { NULL,                    NSM_TwoWay     }, /* LoadingDone       */
 518     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 519     { NULL,                    NSM_TwoWay     }, /* SeqNumberMismatch */
 520     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 521     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 522     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 523     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 524   },
 525   {
 526     /* ExStart: */
 527     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 528     { nsm_packet_received,     NSM_ExStart    }, /* PacaketReceived   */
 529     { NULL,                    NSM_ExStart    }, /* Start             */
 530     { NULL,                    NSM_ExStart    }, /* 2-WayReceived     */
 531     { nsm_negotiation_done,    NSM_Exchange   }, /* NegotiationDone   */
 532     { NULL,                    NSM_ExStart    }, /* ExchangeDone      */
 533     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 534     { NULL,                    NSM_ExStart    }, /* LoadingDone       */
 535     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 536     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 537     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 538     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 539     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 540     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 541   },
 542   {
 543     /* Exchange: */
 544     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 545     { nsm_packet_received,     NSM_Exchange   }, /* PacketReceived    */
 546     { NULL,                    NSM_Exchange   }, /* Start             */
 547     { NULL,                    NSM_Exchange   }, /* 2-WayReceived     */
 548     { NULL,                    NSM_Exchange   }, /* NegotiationDone   */
 549     { nsm_exchange_done,       NSM_DependUpon }, /* ExchangeDone      */
 550     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 551     { NULL,                    NSM_Exchange   }, /* LoadingDone       */
 552     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 553     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 554     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 555     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 556     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 557     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 558   },
 559   {
 560     /* Loading: */
 561     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 562     { nsm_packet_received,     NSM_Loading    }, /* PacketReceived    */
 563     { NULL,                    NSM_Loading    }, /* Start             */
 564     { NULL,                    NSM_Loading    }, /* 2-WayReceived     */
 565     { NULL,                    NSM_Loading    }, /* NegotiationDone   */
 566     { NULL,                    NSM_Loading    }, /* ExchangeDone      */
 567     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 568     { NULL,                    NSM_Full       }, /* LoadingDone       */
 569     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 570     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 571     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 572     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 573     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 574     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 575   },
 576   { /* Full: */
 577     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 578     { nsm_packet_received,     NSM_Full       }, /* PacketReceived    */
 579     { NULL,                    NSM_Full       }, /* Start             */
 580     { NULL,                    NSM_Full       }, /* 2-WayReceived     */
 581     { NULL,                    NSM_Full       }, /* NegotiationDone   */
 582     { NULL,                    NSM_Full       }, /* ExchangeDone      */
 583     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 584     { NULL,                    NSM_Full       }, /* LoadingDone       */
 585     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 586     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 587     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 588     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 589     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 590     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 591   },
 592 };
 593
 594 static const char *ospf_nsm_event_str[] =
 595 {
 596   "NoEvent",
 597   "PacketReceived",
 598   "Start",
 599   "2-WayReceived",
 600   "NegotiationDone",
 601   "ExchangeDone",
 602   "BadLSReq",
 603   "LoadingDone",
 604   "AdjOK?",
 605   "SeqNumberMismatch",
 606   "1-WayReceived",
 607   "KillNbr",
 608   "InactivityTimer",
 609   "LLDown",
 610 };
 611
 612 static void
 613 nsm_notice_state_change (struct ospf_neighbor *nbr, int next_state, int event)
 614 {
 615   /* Logging change of status. */
 616   if (IS_DEBUG_OSPF (nsm, NSM_STATUS))
 617     zlog_debug ("NSM[%s:%s]: State change %s -> %s (%s)",
 618                IF_NAME (nbr->oi), inet_ntoa (nbr->router_id),
 619                LOOKUP (ospf_nsm_state_msg, nbr->state),
 620                LOOKUP (ospf_nsm_state_msg, next_state),
 621                ospf_nsm_event_str [event]);
 622
 623   /* Optionally notify about adjacency changes */
 624   if (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_CHANGES) &&
 625       (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL) ||
 626        (next_state == NSM_Full) || (next_state < nbr->state)))
 627     zlog_notice("AdjChg: Nbr %s on %s: %s -> %s (%s)",
 628                 inet_ntoa (nbr->router_id), IF_NAME (nbr->oi),
 629                 LOOKUP (ospf_nsm_state_msg, nbr->state),
 630                 LOOKUP (ospf_nsm_state_msg, next_state),
 631                 ospf_nsm_event_str [event]);
 632
 633   /* Advance in NSM */
 634   if (next_state > nbr->state)
 635     monotime(&nbr->ts_last_progress);
 636   else /* regression in NSM */
 637     {
 638       monotime(&nbr->ts_last_regress);
 639       nbr->last_regress_str = ospf_nsm_event_str [event];
 640     }
 641
 642 }
 643
 644 static void
 645 nsm_change_state (struct ospf_neighbor *nbr, int state)
 646 {
 647   struct ospf_interface *oi = nbr->oi;
 648   struct ospf_area *vl_area = NULL;
 649   u_char old_state;
 650   int x;
 651   int force = 1;
 652
 653   /* Preserve old status. */
 654   old_state = nbr->state;
 655
 656   /* Change to new status. */
 657   nbr->state = state;
 658
 659   /* Statistics. */
 660   nbr->state_change++;
 661
 662   if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
 663     vl_area = ospf_area_lookup_by_area_id (oi->ospf, oi->vl_data->vl_area_id);
 664
 665   /* Generate NeighborChange ISM event.
 666    *
 667    * In response to NeighborChange, DR election is rerun. The information
 668    * from the election process is required by the router-lsa construction.
 669    *
 670    * Therefore, trigger the event prior to refreshing the LSAs. */
 671   switch (oi->state) {
 672   case ISM_DROther:
 673   case ISM_Backup:
 674   case ISM_DR:
 675     if ((old_state < NSM_TwoWay && state >= NSM_TwoWay) ||
 676         (old_state >= NSM_TwoWay && state < NSM_TwoWay))
 677       OSPF_ISM_EVENT_EXECUTE (oi, ISM_NeighborChange);
 678     break;
 679   default:
 680     /* ISM_PointToPoint -> ISM_Down, ISM_Loopback -> ISM_Down, etc. */
 681     break;
 682   }
 683
 684   /* One of the neighboring routers changes to/from the FULL state. */
 685   if ((old_state != NSM_Full && state == NSM_Full) ||
 686       (old_state == NSM_Full && state != NSM_Full))
 687     {
 688       if (state == NSM_Full)
 689         {
 690           oi->full_nbrs++;
 691           oi->area->full_nbrs++;
 692
 693           ospf_check_abr_status (oi->ospf);
 694
 695           if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 696             if (++vl_area->full_vls == 1)
 697               ospf_schedule_abr_task (oi->ospf);
 698
 699           /* kevinm: refresh any redistributions */
 700           for (x = ZEBRA_ROUTE_SYSTEM; x < ZEBRA_ROUTE_MAX; x++)
 701             {
 702               struct list *red_list;
 703               struct listnode *node;
 704               struct ospf_redist *red;
 705
 706               if (x == ZEBRA_ROUTE_OSPF6)
 707                 continue;
 708
 709               red_list = oi->ospf->redist[x];
 710               if (!red_list)
 711                 continue;
 712
 713               for (ALL_LIST_ELEMENTS_RO(red_list, node, red))
 714                 ospf_external_lsa_refresh_type (oi->ospf, x, red->instance, force);
 715             }
 716           /* XXX: Clearly some thing is wrong with refresh of external LSAs
 717            * this added to hack around defaults not refreshing after a timer
 718            * jump.
 719            */
 720           ospf_external_lsa_refresh_default (oi->ospf);
 721         }
 722       else
 723         {
 724           oi->full_nbrs--;
 725           oi->area->full_nbrs--;
 726
 727           ospf_check_abr_status (oi->ospf);
 728
 729           if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 730             if (vl_area->full_vls > 0)
 731               if (--vl_area->full_vls == 0)
 732                 ospf_schedule_abr_task (oi->ospf);
 733         }
 734
 735       zlog_info ("nsm_change_state(%s, %s -> %s): "
 736                  "scheduling new router-LSA origination",
 737                  inet_ntoa (nbr->router_id),
 738                  LOOKUP(ospf_nsm_state_msg, old_state),
 739                  LOOKUP(ospf_nsm_state_msg, state));
 740
 741       ospf_router_lsa_update_area (oi->area);
 742
 743       if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
 744         {
 745           struct ospf_area *vl_area =
 746             ospf_area_lookup_by_area_id (oi->ospf, oi->vl_data->vl_area_id);
 747
 748           if (vl_area)
 749             ospf_router_lsa_update_area (vl_area);
 750         }
 751
 752       /* Originate network-LSA. */
 753       if (oi->state == ISM_DR)
 754         {
 755           if (oi->network_lsa_self && oi->full_nbrs == 0)
 756             {
 757               ospf_lsa_flush_area (oi->network_lsa_self, oi->area);
 758               ospf_lsa_unlock (&oi->network_lsa_self);
 759               oi->network_lsa_self = NULL;
 760             }
 761           else
 762             ospf_network_lsa_update (oi);
 763         }
 764     }
 765
 766   ospf_opaque_nsm_change (nbr, old_state);
 767
 768   /* State changes from > ExStart to <= ExStart should clear any Exchange
 769    * or Full/LSA Update related lists and state.
 770    * Potential causal events: BadLSReq, SeqNumberMismatch, AdjOK?
 771    */
 772   if ((old_state > NSM_ExStart) && (state <= NSM_ExStart))
 773     nsm_clear_adj (nbr);
 774
 775   /* Start DD exchange protocol */
 776   if (state == NSM_ExStart)
 777     {
 778       if (nbr->dd_seqnum == 0)
 779         nbr->dd_seqnum = (uint32_t)random ();
 780       else
 781         nbr->dd_seqnum++;
 782
 783       nbr->dd_flags = OSPF_DD_FLAG_I|OSPF_DD_FLAG_M|OSPF_DD_FLAG_MS;
 784       ospf_db_desc_send (nbr);
 785     }
 786
 787   /* clear cryptographic sequence number */
 788   if (state == NSM_Down)
 789     nbr->crypt_seqnum = 0;
 790
 791   ospf_bfd_trigger_event(nbr, old_state, state);
 792
 793   /* Preserve old status? */
 794 }
 795
 796 /* Execute NSM event process. */
 797 int
 798 ospf_nsm_event (struct thread *thread)
 799 {
 800   int event;
 801   int next_state;
 802   struct ospf_neighbor *nbr;
 803
 804   nbr = THREAD_ARG (thread);
 805   event = THREAD_VAL (thread);
 806
 807   if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
 808     zlog_debug ("NSM[%s:%s]: %s (%s)", IF_NAME (nbr->oi),
 809                inet_ntoa (nbr->router_id),
 810                LOOKUP (ospf_nsm_state_msg, nbr->state),
 811                ospf_nsm_event_str [event]);
 812
 813   next_state = NSM [nbr->state][event].next_state;
 814
 815   /* Call function. */
 816   if (NSM [nbr->state][event].func != NULL)
 817     {
 818       int func_state = (*(NSM [nbr->state][event].func))(nbr);
 819
 820       if (NSM [nbr->state][event].next_state == NSM_DependUpon)
 821         next_state = func_state;
 822       else if (func_state)
 823         {
 824           /* There's a mismatch between the FSM tables and what an FSM
 825            * action/state-change function returned. State changes which
 826            * do not have conditional/DependUpon next-states should not
 827            * try set next_state.
 828            */
 829           zlog_warn ("NSM[%s:%s]: %s (%s): "
 830                      "Warning: action tried to change next_state to %s",
 831                      IF_NAME (nbr->oi), inet_ntoa (nbr->router_id),
 832                      LOOKUP (ospf_nsm_state_msg, nbr->state),
 833                      ospf_nsm_event_str [event],
 834                      LOOKUP (ospf_nsm_state_msg, func_state));
 835         }
 836     }
 837
 838   assert (next_state != NSM_DependUpon);
 839
 840   /* If state is changed. */
 841   if (next_state != nbr->state)
 842     {
 843       int old_state = nbr->state;
 844
 845       nsm_notice_state_change (nbr, next_state, event);
 846       nsm_change_state (nbr, next_state);
 847
 848       hook_call(ospf_nsm_change, nbr, next_state, old_state);
 849     }
 850
 851   /* Make sure timer is set. */
 852   nsm_timer_set (nbr);
 853
 854   /* When event is NSM_KillNbr, InactivityTimer or LLDown, the neighbor
 855    * is deleted.
 856    *
 857    * Rather than encode knowledge here of which events lead to NBR
 858    * delete, we take our cue from the NSM table, via the dummy
 859    * 'Deleted' neighbour state.
 860    */
 861   if (nbr->state == NSM_Deleted)
 862     ospf_nbr_delete (nbr);
 863
 864   return 0;
 865 }
 866
 867 /* Check loading state. */
 868 void
 869 ospf_check_nbr_loading (struct ospf_neighbor *nbr)
 870 {
 871   if (nbr->state == NSM_Loading)
 872     {
 873       if (ospf_ls_request_isempty (nbr))
 874         OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_LoadingDone);
 875       else if (nbr->ls_req_last == NULL)
 876         ospf_ls_req_event (nbr);
 877     }
 878 }