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 #include "ospfd/ospf_errors.h"
  52
  53 DEFINE_HOOK(ospf_nsm_change,
  54             (struct ospf_neighbor * on, int state, int oldstate),
  55             (on, state, oldstate))
  56
  57 static void nsm_clear_adj(struct ospf_neighbor *);
  58
  59 /* OSPF NSM Timer functions. */
  60 static int 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:%s]: Timer (Inactivity timer expire)",
  69                            IF_NAME(nbr->oi), inet_ntoa(nbr->router_id),
  70                            ospf_get_name(nbr->oi->ospf));
  71
  72         OSPF_NSM_EVENT_SCHEDULE(nbr, NSM_InactivityTimer);
  73
  74         return 0;
  75 }
  76
  77 static int 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:%s]: Timer (DD Retransmit timer expire)",
  86                            IF_NAME(nbr->oi), inet_ntoa(nbr->src),
  87                            ospf_get_name(nbr->oi->ospf));
  88
  89         /* resent last send DD packet. */
  90         assert(nbr->last_send);
  91         ospf_db_desc_resend(nbr);
  92
  93         /* DD Retransmit timer set. */
  94         OSPF_NSM_TIMER_ON(nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
  95
  96         return 0;
  97 }
  98
  99 /* Hook function called after ospf NSM event is occurred.
 100  *
 101  * Set/clear any timers whose condition is implicit to the neighbour
 102  * state. There may be other timers which are set/unset according to other
 103  * state.
 104  *
 105  * We rely on this function to properly clear timers in lower states,
 106  * particularly before deleting a neighbour.
 107  */
 108 static void nsm_timer_set(struct ospf_neighbor *nbr)
 109 {
 110         switch (nbr->state) {
 111         case NSM_Deleted:
 112         case NSM_Down:
 113                 OSPF_NSM_TIMER_OFF(nbr->t_inactivity);
 114                 OSPF_NSM_TIMER_OFF(nbr->t_hello_reply);
 115         /* fallthru */
 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,
 125                                   nbr->v_db_desc);
 126                 OSPF_NSM_TIMER_OFF(nbr->t_ls_upd);
 127                 OSPF_NSM_TIMER_OFF(nbr->t_ls_req);
 128                 break;
 129         case NSM_Exchange:
 130                 OSPF_NSM_TIMER_ON(nbr->t_ls_upd, ospf_ls_upd_timer,
 131                                   nbr->v_ls_upd);
 132                 if (!IS_SET_DD_MS(nbr->dd_flags))
 133                         OSPF_NSM_TIMER_OFF(nbr->t_db_desc);
 134                 break;
 135         case NSM_Loading:
 136         case NSM_Full:
 137         default:
 138                 OSPF_NSM_TIMER_OFF(nbr->t_db_desc);
 139                 break;
 140         }
 141 }
 142
 143 /* 10.4 of RFC2328, indicate whether an adjacency is appropriate with
 144  * the given neighbour
 145  */
 146 static int nsm_should_adj(struct ospf_neighbor *nbr)
 147 {
 148         struct ospf_interface *oi = nbr->oi;
 149
 150         /* These network types must always form adjacencies. */
 151         if (oi->type == OSPF_IFTYPE_POINTOPOINT
 152             || oi->type == OSPF_IFTYPE_POINTOMULTIPOINT
 153             || oi->type == OSPF_IFTYPE_VIRTUALLINK
 154             /* Router itself is the DRouter or the BDRouter. */
 155             || IPV4_ADDR_SAME(&oi->address->u.prefix4, &DR(oi))
 156             || IPV4_ADDR_SAME(&oi->address->u.prefix4, &BDR(oi))
 157             /* Neighboring Router is the DRouter or the BDRouter. */
 158             || IPV4_ADDR_SAME(&nbr->address.u.prefix4, &DR(oi))
 159             || IPV4_ADDR_SAME(&nbr->address.u.prefix4, &BDR(oi)))
 160                 return 1;
 161
 162         return 0;
 163 }
 164
 165 /* OSPF NSM functions. */
 166 static int 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 nsm_start(struct ospf_neighbor *nbr)
 185 {
 186         if (nbr->nbr_nbma)
 187                 OSPF_POLL_TIMER_OFF(nbr->nbr_nbma->t_poll);
 188
 189         OSPF_NSM_TIMER_OFF(nbr->t_inactivity);
 190
 191         OSPF_NSM_TIMER_ON(nbr->t_inactivity, ospf_inactivity_timer,
 192                           nbr->v_inactivity);
 193
 194         /* Send proactive ARP requests */
 195         ospf_proactively_arp(nbr);
 196
 197         return 0;
 198 }
 199
 200 static int nsm_twoway_received(struct ospf_neighbor *nbr)
 201 {
 202         int adj = nsm_should_adj(nbr);
 203
 204         /* Send proactive ARP requests */
 205         if (adj)
 206                 ospf_proactively_arp(nbr);
 207
 208         return (adj ? NSM_ExStart : NSM_TwoWay);
 209 }
 210
 211 int ospf_db_summary_count(struct ospf_neighbor *nbr)
 212 {
 213         return ospf_lsdb_count_all(&nbr->db_sum);
 214 }
 215
 216 int ospf_db_summary_isempty(struct ospf_neighbor *nbr)
 217 {
 218         return ospf_lsdb_isempty(&nbr->db_sum);
 219 }
 220
 221 static int ospf_db_summary_add(struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
 222 {
 223         switch (lsa->data->type) {
 224         case OSPF_OPAQUE_LINK_LSA:
 225                 /* Exclude type-9 LSAs that does not have the same "oi" with
 226                  * "nbr". */
 227                 if (ospf_if_exists(lsa->oi) != nbr->oi)
 228                         return 0;
 229                 break;
 230         case OSPF_OPAQUE_AREA_LSA:
 231                 /*
 232                  * It is assured by the caller function "nsm_negotiation_done()"
 233                  * that every given LSA belongs to the same area with "nbr".
 234                  */
 235                 break;
 236         case OSPF_OPAQUE_AS_LSA:
 237         default:
 238                 break;
 239         }
 240
 241         /* Stay away from any Local Translated Type-7 LSAs */
 242         if (CHECK_FLAG(lsa->flags, OSPF_LSA_LOCAL_XLT))
 243                 return 0;
 244
 245         if (IS_LSA_MAXAGE(lsa))
 246                 ospf_ls_retransmit_add(nbr, lsa);
 247         else
 248                 ospf_lsdb_add(&nbr->db_sum, lsa);
 249
 250         return 0;
 251 }
 252
 253 void ospf_db_summary_clear(struct ospf_neighbor *nbr)
 254 {
 255         struct ospf_lsdb *lsdb;
 256         int i;
 257
 258         lsdb = &nbr->db_sum;
 259         for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++) {
 260                 struct route_table *table = lsdb->type[i].db;
 261                 struct route_node *rn;
 262
 263                 for (rn = route_top(table); rn; rn = route_next(rn))
 264                         if (rn->info)
 265                                 ospf_lsdb_delete(&nbr->db_sum, rn->info);
 266         }
 267 }
 268
 269
 270 /* The area link state database consists of the router-LSAs,
 271    network-LSAs and summary-LSAs contained in the area structure,
 272    along with the AS-external-LSAs contained in the global structure.
 273    AS-external-LSAs are omitted from a virtual neighbor's Database
 274    summary list.  AS-external-LSAs are omitted from the Database
 275    summary list if the area has been configured as a stub. */
 276 static int nsm_negotiation_done(struct ospf_neighbor *nbr)
 277 {
 278         struct ospf_area *area = nbr->oi->area;
 279         struct ospf_lsa *lsa;
 280         struct route_node *rn;
 281
 282         /* Send proactive ARP requests */
 283         ospf_proactively_arp(nbr);
 284
 285         LSDB_LOOP (ROUTER_LSDB(area), rn, lsa)
 286                 ospf_db_summary_add(nbr, lsa);
 287         LSDB_LOOP (NETWORK_LSDB(area), rn, lsa)
 288                 ospf_db_summary_add(nbr, lsa);
 289         LSDB_LOOP (SUMMARY_LSDB(area), rn, lsa)
 290                 ospf_db_summary_add(nbr, lsa);
 291         LSDB_LOOP (ASBR_SUMMARY_LSDB(area), rn, lsa)
 292                 ospf_db_summary_add(nbr, lsa);
 293
 294         /* Process only if the neighbor is opaque capable. */
 295         if (CHECK_FLAG(nbr->options, OSPF_OPTION_O)) {
 296                 LSDB_LOOP (OPAQUE_LINK_LSDB(area), rn, lsa)
 297                         ospf_db_summary_add(nbr, lsa);
 298                 LSDB_LOOP (OPAQUE_AREA_LSDB(area), rn, lsa)
 299                         ospf_db_summary_add(nbr, lsa);
 300         }
 301
 302         if (CHECK_FLAG(nbr->options, OSPF_OPTION_NP)) {
 303                 LSDB_LOOP (NSSA_LSDB(area), rn, lsa)
 304                         ospf_db_summary_add(nbr, lsa);
 305         }
 306
 307         if (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 308             && area->external_routing == OSPF_AREA_DEFAULT)
 309                 LSDB_LOOP (EXTERNAL_LSDB(nbr->oi->ospf), rn, lsa)
 310                         ospf_db_summary_add(nbr, lsa);
 311
 312         if (CHECK_FLAG(nbr->options, OSPF_OPTION_O)
 313             && (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 314                 && area->external_routing == OSPF_AREA_DEFAULT))
 315                 LSDB_LOOP (OPAQUE_AS_LSDB(nbr->oi->ospf), rn, lsa)
 316                         ospf_db_summary_add(nbr, lsa);
 317
 318         return 0;
 319 }
 320
 321 static int nsm_exchange_done(struct ospf_neighbor *nbr)
 322 {
 323         if (ospf_ls_request_isempty(nbr))
 324                 return NSM_Full;
 325
 326         /* Send Link State Request. */
 327         if (nbr->t_ls_req == NULL)
 328                 ospf_ls_req_send(nbr);
 329
 330         return NSM_Loading;
 331 }
 332
 333 static int nsm_adj_ok(struct ospf_neighbor *nbr)
 334 {
 335         int next_state = nbr->state;
 336         int adj = nsm_should_adj(nbr);
 337
 338         if (nbr->state == NSM_TwoWay && adj == 1) {
 339                 next_state = NSM_ExStart;
 340
 341                 /* Send proactive ARP requests */
 342                 ospf_proactively_arp(nbr);
 343         } else if (nbr->state >= NSM_ExStart && adj == 0)
 344                 next_state = NSM_TwoWay;
 345
 346         return next_state;
 347 }
 348
 349 /* Clear adjacency related state for a neighbour, intended where nbr
 350  * transitions from > ExStart (i.e. a Full or forming adjacency)
 351  * to <= ExStart.
 352  */
 353 static void nsm_clear_adj(struct ospf_neighbor *nbr)
 354 {
 355         /* Clear Database Summary list. */
 356         if (!ospf_db_summary_isempty(nbr))
 357                 ospf_db_summary_clear(nbr);
 358
 359         /* Clear Link State Request list. */
 360         if (!ospf_ls_request_isempty(nbr))
 361                 ospf_ls_request_delete_all(nbr);
 362
 363         /* Clear Link State Retransmission list. */
 364         if (!ospf_ls_retransmit_isempty(nbr))
 365                 ospf_ls_retransmit_clear(nbr);
 366
 367         if (CHECK_FLAG(nbr->options, OSPF_OPTION_O))
 368                 UNSET_FLAG(nbr->options, OSPF_OPTION_O);
 369 }
 370
 371 static int nsm_kill_nbr(struct ospf_neighbor *nbr)
 372 {
 373         /* killing nbr_self is invalid */
 374         if (nbr == nbr->oi->nbr_self) {
 375                 assert(nbr != nbr->oi->nbr_self);
 376                 return 0;
 377         }
 378
 379         if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma != NULL) {
 380                 struct ospf_nbr_nbma *nbr_nbma = nbr->nbr_nbma;
 381
 382                 nbr_nbma->nbr = NULL;
 383                 nbr_nbma->state_change = nbr->state_change;
 384
 385                 nbr->nbr_nbma = NULL;
 386
 387                 OSPF_POLL_TIMER_ON(nbr_nbma->t_poll, ospf_poll_timer,
 388                                    nbr_nbma->v_poll);
 389
 390                 if (IS_DEBUG_OSPF(nsm, NSM_EVENTS))
 391                         zlog_debug(
 392                                 "NSM[%s:%s:%s]: Down (PollIntervalTimer scheduled)",
 393                                 IF_NAME(nbr->oi),
 394                                 inet_ntoa(nbr->address.u.prefix4),
 395                                 ospf_get_name(nbr->oi->ospf));
 396         }
 397
 398         return 0;
 399 }
 400
 401 /* Neighbor State Machine */
 402 const struct {
 403         int (*func)(struct ospf_neighbor *);
 404         int next_state;
 405 } NSM[OSPF_NSM_STATE_MAX][OSPF_NSM_EVENT_MAX] = {
 406         {
 407                 /* DependUpon: dummy state. */
 408                 {NULL, NSM_DependUpon}, /* NoEvent           */
 409                 {NULL, NSM_DependUpon}, /* PacketReceived    */
 410                 {NULL, NSM_DependUpon}, /* Start             */
 411                 {NULL, NSM_DependUpon}, /* 2-WayReceived     */
 412                 {NULL, NSM_DependUpon}, /* NegotiationDone   */
 413                 {NULL, NSM_DependUpon}, /* ExchangeDone      */
 414                 {NULL, NSM_DependUpon}, /* BadLSReq          */
 415                 {NULL, NSM_DependUpon}, /* LoadingDone       */
 416                 {NULL, NSM_DependUpon}, /* AdjOK?            */
 417                 {NULL, NSM_DependUpon}, /* SeqNumberMismatch */
 418                 {NULL, NSM_DependUpon}, /* 1-WayReceived     */
 419                 {NULL, NSM_DependUpon}, /* KillNbr           */
 420                 {NULL, NSM_DependUpon}, /* InactivityTimer   */
 421                 {NULL, NSM_DependUpon}, /* LLDown            */
 422         },
 423         {
 424                 /* Deleted: dummy state. */
 425                 {NULL, NSM_Deleted}, /* NoEvent           */
 426                 {NULL, NSM_Deleted}, /* PacketReceived    */
 427                 {NULL, NSM_Deleted}, /* Start             */
 428                 {NULL, NSM_Deleted}, /* 2-WayReceived     */
 429                 {NULL, NSM_Deleted}, /* NegotiationDone   */
 430                 {NULL, NSM_Deleted}, /* ExchangeDone      */
 431                 {NULL, NSM_Deleted}, /* BadLSReq          */
 432                 {NULL, NSM_Deleted}, /* LoadingDone       */
 433                 {NULL, NSM_Deleted}, /* AdjOK?            */
 434                 {NULL, NSM_Deleted}, /* SeqNumberMismatch */
 435                 {NULL, NSM_Deleted}, /* 1-WayReceived     */
 436                 {NULL, NSM_Deleted}, /* KillNbr           */
 437                 {NULL, NSM_Deleted}, /* InactivityTimer   */
 438                 {NULL, NSM_Deleted}, /* LLDown            */
 439         },
 440         {
 441                 /* Down: */
 442                 {NULL, NSM_DependUpon},          /* NoEvent           */
 443                 {nsm_packet_received, NSM_Init}, /* PacketReceived    */
 444                 {nsm_start, NSM_Attempt},       /* Start             */
 445                 {NULL, NSM_Down},                /* 2-WayReceived     */
 446                 {NULL, NSM_Down},                /* NegotiationDone   */
 447                 {NULL, NSM_Down},                /* ExchangeDone      */
 448                 {NULL, NSM_Down},                /* BadLSReq          */
 449                 {NULL, NSM_Down},                /* LoadingDone       */
 450                 {NULL, NSM_Down},                /* AdjOK?            */
 451                 {NULL, NSM_Down},                /* SeqNumberMismatch */
 452                 {NULL, NSM_Down},                /* 1-WayReceived     */
 453                 {nsm_kill_nbr, NSM_Deleted},     /* KillNbr           */
 454                 {nsm_kill_nbr, NSM_Deleted},     /* InactivityTimer   */
 455                 {nsm_kill_nbr, NSM_Deleted},     /* LLDown            */
 456         },
 457         {
 458                 /* Attempt: */
 459                 {NULL, NSM_DependUpon},          /* NoEvent           */
 460                 {nsm_packet_received, NSM_Init}, /* PacketReceived    */
 461                 {NULL, NSM_Attempt},             /* Start             */
 462                 {NULL, NSM_Attempt},             /* 2-WayReceived     */
 463                 {NULL, NSM_Attempt},             /* NegotiationDone   */
 464                 {NULL, NSM_Attempt},             /* ExchangeDone      */
 465                 {NULL, NSM_Attempt},             /* BadLSReq          */
 466                 {NULL, NSM_Attempt},             /* LoadingDone       */
 467                 {NULL, NSM_Attempt},             /* AdjOK?            */
 468                 {NULL, NSM_Attempt},             /* SeqNumberMismatch */
 469                 {NULL, NSM_Attempt},             /* 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                 /* Init: */
 476                 {NULL, NSM_DependUpon},                /* NoEvent           */
 477                 {nsm_packet_received, NSM_Init},       /* PacketReceived    */
 478                 {NULL, NSM_Init},                      /* Start             */
 479                 {nsm_twoway_received, NSM_DependUpon}, /* 2-WayReceived     */
 480                 {NULL, NSM_Init},                      /* NegotiationDone   */
 481                 {NULL, NSM_Init},                      /* ExchangeDone      */
 482                 {NULL, NSM_Init},                      /* BadLSReq          */
 483                 {NULL, NSM_Init},                      /* LoadingDone       */
 484                 {NULL, NSM_Init},                      /* AdjOK?            */
 485                 {NULL, NSM_Init},                      /* SeqNumberMismatch */
 486                 {NULL, NSM_Init},                      /* 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                 /* 2-Way: */
 493                 {NULL, NSM_DependUpon},            /* NoEvent           */
 494                 {nsm_packet_received, NSM_TwoWay}, /* HelloReceived     */
 495                 {NULL, NSM_TwoWay},                /* Start             */
 496                 {NULL, NSM_TwoWay},                /* 2-WayReceived     */
 497                 {NULL, NSM_TwoWay},                /* NegotiationDone   */
 498                 {NULL, NSM_TwoWay},                /* ExchangeDone      */
 499                 {NULL, NSM_TwoWay},                /* BadLSReq          */
 500                 {NULL, NSM_TwoWay},                /* LoadingDone       */
 501                 {nsm_adj_ok, NSM_DependUpon},      /* AdjOK?            */
 502                 {NULL, NSM_TwoWay},                /* 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                 /* ExStart: */
 510                 {NULL, NSM_DependUpon},               /* NoEvent           */
 511                 {nsm_packet_received, NSM_ExStart},   /* PacaketReceived   */
 512                 {NULL, NSM_ExStart},                  /* Start             */
 513                 {NULL, NSM_ExStart},                  /* 2-WayReceived     */
 514                 {nsm_negotiation_done, NSM_Exchange}, /* NegotiationDone   */
 515                 {NULL, NSM_ExStart},                  /* ExchangeDone      */
 516                 {NULL, NSM_ExStart},                  /* BadLSReq          */
 517                 {NULL, NSM_ExStart},                  /* LoadingDone       */
 518                 {nsm_adj_ok, NSM_DependUpon},    /* AdjOK?            */
 519                 {NULL, NSM_ExStart},                  /* 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                 /* Exchange: */
 527                 {NULL, NSM_DependUpon},              /* NoEvent           */
 528                 {nsm_packet_received, NSM_Exchange}, /* PacketReceived    */
 529                 {NULL, NSM_Exchange},                /* Start             */
 530                 {NULL, NSM_Exchange},                /* 2-WayReceived     */
 531                 {NULL, NSM_Exchange},                /* NegotiationDone   */
 532                 {nsm_exchange_done, NSM_DependUpon}, /* ExchangeDone      */
 533                 {NULL, NSM_ExStart},                 /* BadLSReq          */
 534                 {NULL, NSM_Exchange},                /* 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                 /* Loading: */
 544                 {NULL, NSM_DependUpon},             /* NoEvent           */
 545                 {nsm_packet_received, NSM_Loading}, /* PacketReceived    */
 546                 {NULL, NSM_Loading},                /* Start             */
 547                 {NULL, NSM_Loading},                /* 2-WayReceived     */
 548                 {NULL, NSM_Loading},                /* NegotiationDone   */
 549                 {NULL, NSM_Loading},                /* ExchangeDone      */
 550                 {NULL, NSM_ExStart},                /* BadLSReq          */
 551                 {NULL, NSM_Full},                   /* 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                 /* Full: */
 561                 {NULL, NSM_DependUpon},          /* NoEvent           */
 562                 {nsm_packet_received, NSM_Full}, /* PacketReceived    */
 563                 {NULL, NSM_Full},                /* Start             */
 564                 {NULL, NSM_Full},                /* 2-WayReceived     */
 565                 {NULL, NSM_Full},                /* NegotiationDone   */
 566                 {NULL, NSM_Full},                /* 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 };
 577
 578 static const char *const ospf_nsm_event_str[] = {
 579         "NoEvent",         "PacketReceived",  "Start",
 580         "2-WayReceived",     "NegotiationDone", "ExchangeDone",
 581         "BadLSReq",       "LoadingDone",     "AdjOK?",
 582         "SeqNumberMismatch", "1-WayReceived",   "KillNbr",
 583         "InactivityTimer",   "LLDown",
 584 };
 585
 586 static void nsm_notice_state_change(struct ospf_neighbor *nbr, int next_state,
 587                                     int event)
 588 {
 589         /* Logging change of status. */
 590         if (IS_DEBUG_OSPF(nsm, NSM_STATUS))
 591                 zlog_debug("NSM[%s:%s:%s]: State change %s -> %s (%s)",
 592                            IF_NAME(nbr->oi), inet_ntoa(nbr->router_id),
 593                            ospf_get_name(nbr->oi->ospf),
 594                            lookup_msg(ospf_nsm_state_msg, nbr->state, NULL),
 595                            lookup_msg(ospf_nsm_state_msg, next_state, NULL),
 596                            ospf_nsm_event_str[event]);
 597
 598         /* Optionally notify about adjacency changes */
 599         if (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_CHANGES)
 600             && (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL)
 601                 || (next_state == NSM_Full) || (next_state < nbr->state)))
 602                 zlog_notice("AdjChg: Nbr %s(%s) on %s: %s -> %s (%s)",
 603                             inet_ntoa(nbr->router_id),
 604                             ospf_get_name(nbr->oi->ospf), IF_NAME(nbr->oi),
 605                             lookup_msg(ospf_nsm_state_msg, nbr->state, NULL),
 606                             lookup_msg(ospf_nsm_state_msg, next_state, NULL),
 607                             ospf_nsm_event_str[event]);
 608
 609         /* Advance in NSM */
 610         if (next_state > nbr->state)
 611                 monotime(&nbr->ts_last_progress);
 612         else /* regression in NSM */
 613         {
 614                 monotime(&nbr->ts_last_regress);
 615                 nbr->last_regress_str = ospf_nsm_event_str[event];
 616         }
 617 }
 618
 619 static void nsm_change_state(struct ospf_neighbor *nbr, int state)
 620 {
 621         struct ospf_interface *oi = nbr->oi;
 622         struct ospf_area *vl_area = NULL;
 623         uint8_t old_state;
 624
 625         /* Preserve old status. */
 626         old_state = nbr->state;
 627
 628         /* Change to new status. */
 629         nbr->state = state;
 630
 631         /* Statistics. */
 632         nbr->state_change++;
 633
 634         if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
 635                 vl_area = ospf_area_lookup_by_area_id(oi->ospf,
 636                                                       oi->vl_data->vl_area_id);
 637
 638         /* Generate NeighborChange ISM event.
 639          *
 640          * In response to NeighborChange, DR election is rerun. The information
 641          * from the election process is required by the router-lsa construction.
 642          *
 643          * Therefore, trigger the event prior to refreshing the LSAs. */
 644         switch (oi->state) {
 645         case ISM_DROther:
 646         case ISM_Backup:
 647         case ISM_DR:
 648                 if ((old_state < NSM_TwoWay && state >= NSM_TwoWay)
 649                     || (old_state >= NSM_TwoWay && state < NSM_TwoWay))
 650                         OSPF_ISM_EVENT_EXECUTE(oi, ISM_NeighborChange);
 651                 break;
 652         default:
 653                 /* ISM_PointToPoint -> ISM_Down, ISM_Loopback -> ISM_Down, etc.
 654                  */
 655                 break;
 656         }
 657
 658         /* One of the neighboring routers changes to/from the FULL state. */
 659         if ((old_state != NSM_Full && state == NSM_Full)
 660             || (old_state == NSM_Full && state != NSM_Full)) {
 661                 if (state == NSM_Full) {
 662                         oi->full_nbrs++;
 663                         oi->area->full_nbrs++;
 664
 665                         ospf_check_abr_status(oi->ospf);
 666
 667                         if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 668                                 if (++vl_area->full_vls == 1)
 669                                         ospf_schedule_abr_task(oi->ospf);
 670                 } else {
 671                         oi->full_nbrs--;
 672                         oi->area->full_nbrs--;
 673
 674                         ospf_check_abr_status(oi->ospf);
 675
 676                         if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 677                                 if (vl_area->full_vls > 0)
 678                                         if (--vl_area->full_vls == 0)
 679                                                 ospf_schedule_abr_task(
 680                                                         oi->ospf);
 681                 }
 682
 683                 if (CHECK_FLAG(oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL))
 684                         zlog_info(
 685                                 "%s:[%s:%s], %s -> %s): "
 686                                 "scheduling new router-LSA origination",
 687                                 __PRETTY_FUNCTION__, inet_ntoa(nbr->router_id),
 688                                 ospf_get_name(oi->ospf),
 689                                 lookup_msg(ospf_nsm_state_msg, old_state, NULL),
 690                                 lookup_msg(ospf_nsm_state_msg, state, NULL));
 691
 692                 ospf_router_lsa_update_area(oi->area);
 693
 694                 if (oi->type == OSPF_IFTYPE_VIRTUALLINK) {
 695                         vl_area = ospf_area_lookup_by_area_id(
 696                                 oi->ospf, oi->vl_data->vl_area_id);
 697
 698                         if (vl_area)
 699                                 ospf_router_lsa_update_area(vl_area);
 700                 }
 701
 702                 /* Originate network-LSA. */
 703                 if (oi->state == ISM_DR) {
 704                         if (oi->network_lsa_self && oi->full_nbrs == 0) {
 705                                 ospf_lsa_flush_area(oi->network_lsa_self,
 706                                                     oi->area);
 707                                 ospf_lsa_unlock(&oi->network_lsa_self);
 708                                 oi->network_lsa_self = NULL;
 709                         } else
 710                                 ospf_network_lsa_update(oi);
 711                 }
 712         }
 713
 714         ospf_opaque_nsm_change(nbr, old_state);
 715
 716         /* State changes from > ExStart to <= ExStart should clear any Exchange
 717          * or Full/LSA Update related lists and state.
 718          * Potential causal events: BadLSReq, SeqNumberMismatch, AdjOK?
 719          */
 720         if ((old_state > NSM_ExStart) && (state <= NSM_ExStart))
 721                 nsm_clear_adj(nbr);
 722
 723         /* Start DD exchange protocol */
 724         if (state == NSM_ExStart) {
 725                 if (nbr->dd_seqnum == 0)
 726                         nbr->dd_seqnum = (uint32_t)random();
 727                 else
 728                         nbr->dd_seqnum++;
 729
 730                 nbr->dd_flags =
 731                         OSPF_DD_FLAG_I | OSPF_DD_FLAG_M | OSPF_DD_FLAG_MS;
 732                 if (CHECK_FLAG(oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL))
 733                         zlog_info(
 734                                 "%s: Intializing [DD]: %s with seqnum:%x , flags:%x",
 735                                 (oi->ospf->name) ? oi->ospf->name
 736                                                  : VRF_DEFAULT_NAME,
 737                                 inet_ntoa(nbr->router_id), nbr->dd_seqnum,
 738                                 nbr->dd_flags);
 739                 ospf_db_desc_send(nbr);
 740         }
 741
 742         /* clear cryptographic sequence number */
 743         if (state == NSM_Down)
 744                 nbr->crypt_seqnum = 0;
 745
 746         ospf_bfd_trigger_event(nbr, old_state, state);
 747
 748         /* Preserve old status? */
 749 }
 750
 751 /* Execute NSM event process. */
 752 int ospf_nsm_event(struct thread *thread)
 753 {
 754         int event;
 755         int next_state;
 756         struct ospf_neighbor *nbr;
 757
 758         nbr = THREAD_ARG(thread);
 759         event = THREAD_VAL(thread);
 760
 761         if (IS_DEBUG_OSPF(nsm, NSM_EVENTS))
 762                 zlog_debug("NSM[%s:%s:%s]: %s (%s)", IF_NAME(nbr->oi),
 763                            inet_ntoa(nbr->router_id),
 764                            ospf_get_name(nbr->oi->ospf),
 765                            lookup_msg(ospf_nsm_state_msg, nbr->state, NULL),
 766                            ospf_nsm_event_str[event]);
 767
 768         next_state = NSM[nbr->state][event].next_state;
 769
 770         /* Call function. */
 771         if (NSM[nbr->state][event].func != NULL) {
 772                 int func_state = (*(NSM[nbr->state][event].func))(nbr);
 773
 774                 if (NSM[nbr->state][event].next_state == NSM_DependUpon)
 775                         next_state = func_state;
 776                 else if (func_state) {
 777                         /* There's a mismatch between the FSM tables and what an
 778                          * FSM
 779                          * action/state-change function returned. State changes
 780                          * which
 781                          * do not have conditional/DependUpon next-states should
 782                          * not
 783                          * try set next_state.
 784                          */
 785                         flog_err(
 786                                 EC_OSPF_FSM_INVALID_STATE,
 787                                 "NSM[%s:%s:%s]: %s (%s): "
 788                                 "Warning: action tried to change next_state to %s",
 789                                 IF_NAME(nbr->oi), inet_ntoa(nbr->router_id),
 790                                 ospf_get_name(nbr->oi->ospf),
 791                                 lookup_msg(ospf_nsm_state_msg, nbr->state,
 792                                            NULL),
 793                                 ospf_nsm_event_str[event],
 794                                 lookup_msg(ospf_nsm_state_msg, func_state,
 795                                            NULL));
 796                 }
 797         }
 798
 799         assert(next_state != NSM_DependUpon);
 800
 801         /* If state is changed. */
 802         if (next_state != nbr->state) {
 803                 int old_state = nbr->state;
 804
 805                 nsm_notice_state_change(nbr, next_state, event);
 806                 nsm_change_state(nbr, next_state);
 807
 808                 hook_call(ospf_nsm_change, nbr, next_state, old_state);
 809         }
 810
 811         /* Make sure timer is set. */
 812         nsm_timer_set(nbr);
 813
 814         /* When event is NSM_KillNbr, InactivityTimer or LLDown, the neighbor
 815          * is deleted.
 816          *
 817          * Rather than encode knowledge here of which events lead to NBR
 818          * delete, we take our cue from the NSM table, via the dummy
 819          * 'Deleted' neighbour state.
 820          */
 821         if (nbr->state == NSM_Deleted)
 822                 ospf_nbr_delete(nbr);
 823
 824         return 0;
 825 }
 826
 827 /* Check loading state. */
 828 void ospf_check_nbr_loading(struct ospf_neighbor *nbr)
 829 {
 830         if (nbr->state == NSM_Loading) {
 831                 if (ospf_ls_request_isempty(nbr))
 832                         OSPF_NSM_EVENT_SCHEDULE(nbr, NSM_LoadingDone);
 833                 else if (nbr->ls_req_last == NULL)
 834                         ospf_ls_req_event(nbr);
 835         }
 836 }