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 #include "network.h"
  37
  38 #include "ospfd/ospfd.h"
  39 #include "ospfd/ospf_interface.h"
  40 #include "ospfd/ospf_ism.h"
  41 #include "ospfd/ospf_asbr.h"
  42 #include "ospfd/ospf_lsa.h"
  43 #include "ospfd/ospf_lsdb.h"
  44 #include "ospfd/ospf_neighbor.h"
  45 #include "ospfd/ospf_nsm.h"
  46 #include "ospfd/ospf_network.h"
  47 #include "ospfd/ospf_packet.h"
  48 #include "ospfd/ospf_dump.h"
  49 #include "ospfd/ospf_flood.h"
  50 #include "ospfd/ospf_abr.h"
  51 #include "ospfd/ospf_bfd.h"
  52 #include "ospfd/ospf_errors.h"
  53
  54 DEFINE_HOOK(ospf_nsm_change,
  55             (struct ospf_neighbor * on, int state, int oldstate),
  56             (on, state, oldstate));
  57
  58 static void nsm_clear_adj(struct ospf_neighbor *);
  59
  60 /* OSPF NSM Timer functions. */
  61 static int ospf_inactivity_timer(struct thread *thread)
  62 {
  63         struct ospf_neighbor *nbr;
  64
  65         nbr = THREAD_ARG(thread);
  66         nbr->t_inactivity = NULL;
  67
  68         if (IS_DEBUG_OSPF(nsm, NSM_TIMERS))
  69                 zlog_debug("NSM[%s:%pI4:%s]: Timer (Inactivity timer expire)",
  70                            IF_NAME(nbr->oi), &nbr->router_id,
  71                            ospf_get_name(nbr->oi->ospf));
  72
  73         /* Dont trigger NSM_InactivityTimer event , if the current
  74          * router acting as HELPER for this neighbour.
  75          */
  76         if (!OSPF_GR_IS_ACTIVE_HELPER(nbr))
  77                 OSPF_NSM_EVENT_SCHEDULE(nbr, NSM_InactivityTimer);
  78         else if (IS_DEBUG_OSPF_GR_HELPER)
  79                 zlog_debug(
  80                         "%s, Acting as HELPER for this neighbour, So inactivitytimer event will not be fired.",
  81                         __func__);
  82
  83         return 0;
  84 }
  85
  86 static int ospf_db_desc_timer(struct thread *thread)
  87 {
  88         struct ospf_neighbor *nbr;
  89
  90         nbr = THREAD_ARG(thread);
  91         nbr->t_db_desc = NULL;
  92
  93         if (IS_DEBUG_OSPF(nsm, NSM_TIMERS))
  94                 zlog_debug("NSM[%s:%pI4:%s]: Timer (DD Retransmit timer expire)",
  95                            IF_NAME(nbr->oi), &nbr->src,
  96                            ospf_get_name(nbr->oi->ospf));
  97
  98         /* resent last send DD packet. */
  99         assert(nbr->last_send);
 100         ospf_db_desc_resend(nbr);
 101
 102         /* DD Retransmit timer set. */
 103         OSPF_NSM_TIMER_ON(nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
 104
 105         return 0;
 106 }
 107
 108 /* Hook function called after ospf NSM event is occurred.
 109  *
 110  * Set/clear any timers whose condition is implicit to the neighbour
 111  * state. There may be other timers which are set/unset according to other
 112  * state.
 113  *
 114  * We rely on this function to properly clear timers in lower states,
 115  * particularly before deleting a neighbour.
 116  */
 117 static void nsm_timer_set(struct ospf_neighbor *nbr)
 118 {
 119         switch (nbr->state) {
 120         case NSM_Deleted:
 121         case NSM_Down:
 122                 OSPF_NSM_TIMER_OFF(nbr->t_inactivity);
 123                 OSPF_NSM_TIMER_OFF(nbr->t_hello_reply);
 124         /* fallthru */
 125         case NSM_Attempt:
 126         case NSM_Init:
 127         case NSM_TwoWay:
 128                 OSPF_NSM_TIMER_OFF(nbr->t_db_desc);
 129                 OSPF_NSM_TIMER_OFF(nbr->t_ls_upd);
 130                 OSPF_NSM_TIMER_OFF(nbr->t_ls_req);
 131                 break;
 132         case NSM_ExStart:
 133                 OSPF_NSM_TIMER_ON(nbr->t_db_desc, ospf_db_desc_timer,
 134                                   nbr->v_db_desc);
 135                 OSPF_NSM_TIMER_OFF(nbr->t_ls_upd);
 136                 OSPF_NSM_TIMER_OFF(nbr->t_ls_req);
 137                 break;
 138         case NSM_Exchange:
 139                 OSPF_NSM_TIMER_ON(nbr->t_ls_upd, ospf_ls_upd_timer,
 140                                   nbr->v_ls_upd);
 141                 if (!IS_SET_DD_MS(nbr->dd_flags))
 142                         OSPF_NSM_TIMER_OFF(nbr->t_db_desc);
 143                 break;
 144         case NSM_Loading:
 145         case NSM_Full:
 146         default:
 147                 OSPF_NSM_TIMER_OFF(nbr->t_db_desc);
 148                 break;
 149         }
 150 }
 151
 152 /* 10.4 of RFC2328, indicate whether an adjacency is appropriate with
 153  * the given neighbour
 154  */
 155 int nsm_should_adj(struct ospf_neighbor *nbr)
 156 {
 157         struct ospf_interface *oi = nbr->oi;
 158
 159         /* These network types must always form adjacencies. */
 160         if (oi->type == OSPF_IFTYPE_POINTOPOINT
 161             || oi->type == OSPF_IFTYPE_POINTOMULTIPOINT
 162             || oi->type == OSPF_IFTYPE_VIRTUALLINK
 163             /* Router itself is the DRouter or the BDRouter. */
 164             || IPV4_ADDR_SAME(&oi->address->u.prefix4, &DR(oi))
 165             || IPV4_ADDR_SAME(&oi->address->u.prefix4, &BDR(oi))
 166             /* Neighboring Router is the DRouter or the BDRouter. */
 167             || IPV4_ADDR_SAME(&nbr->address.u.prefix4, &DR(oi))
 168             || IPV4_ADDR_SAME(&nbr->address.u.prefix4, &BDR(oi)))
 169                 return 1;
 170
 171         return 0;
 172 }
 173
 174 /* OSPF NSM functions. */
 175 static int nsm_packet_received(struct ospf_neighbor *nbr)
 176 {
 177         /* Start or Restart Inactivity Timer. */
 178         OSPF_NSM_TIMER_OFF(nbr->t_inactivity);
 179
 180         OSPF_NSM_TIMER_ON(nbr->t_inactivity, ospf_inactivity_timer,
 181                           nbr->v_inactivity);
 182
 183         if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma)
 184                 OSPF_POLL_TIMER_OFF(nbr->nbr_nbma->t_poll);
 185
 186         /* Send proactive ARP requests */
 187         if (nbr->state < NSM_Exchange)
 188                 ospf_proactively_arp(nbr);
 189
 190         return 0;
 191 }
 192
 193 static int nsm_start(struct ospf_neighbor *nbr)
 194 {
 195         if (nbr->nbr_nbma)
 196                 OSPF_POLL_TIMER_OFF(nbr->nbr_nbma->t_poll);
 197
 198         OSPF_NSM_TIMER_OFF(nbr->t_inactivity);
 199
 200         OSPF_NSM_TIMER_ON(nbr->t_inactivity, ospf_inactivity_timer,
 201                           nbr->v_inactivity);
 202
 203         /* Send proactive ARP requests */
 204         ospf_proactively_arp(nbr);
 205
 206         return 0;
 207 }
 208
 209 static int nsm_twoway_received(struct ospf_neighbor *nbr)
 210 {
 211         int adj = nsm_should_adj(nbr);
 212
 213         /* Send proactive ARP requests */
 214         if (adj)
 215                 ospf_proactively_arp(nbr);
 216
 217         return (adj ? NSM_ExStart : NSM_TwoWay);
 218 }
 219
 220 int ospf_db_summary_count(struct ospf_neighbor *nbr)
 221 {
 222         return ospf_lsdb_count_all(&nbr->db_sum);
 223 }
 224
 225 int ospf_db_summary_isempty(struct ospf_neighbor *nbr)
 226 {
 227         return ospf_lsdb_isempty(&nbr->db_sum);
 228 }
 229
 230 static int ospf_db_summary_add(struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
 231 {
 232         switch (lsa->data->type) {
 233         case OSPF_OPAQUE_LINK_LSA:
 234                 /* Exclude type-9 LSAs that does not have the same "oi" with
 235                  * "nbr". */
 236                 if (ospf_if_exists(lsa->oi) != nbr->oi)
 237                         return 0;
 238                 break;
 239         case OSPF_OPAQUE_AREA_LSA:
 240                 /*
 241                  * It is assured by the caller function "nsm_negotiation_done()"
 242                  * that every given LSA belongs to the same area with "nbr".
 243                  */
 244                 break;
 245         case OSPF_OPAQUE_AS_LSA:
 246         default:
 247                 break;
 248         }
 249
 250         /* Stay away from any Local Translated Type-7 LSAs */
 251         if (CHECK_FLAG(lsa->flags, OSPF_LSA_LOCAL_XLT))
 252                 return 0;
 253
 254         if (IS_LSA_MAXAGE(lsa))
 255                 ospf_ls_retransmit_add(nbr, lsa);
 256         else
 257                 ospf_lsdb_add(&nbr->db_sum, lsa);
 258
 259         return 0;
 260 }
 261
 262 void ospf_db_summary_clear(struct ospf_neighbor *nbr)
 263 {
 264         struct ospf_lsdb *lsdb;
 265         int i;
 266
 267         lsdb = &nbr->db_sum;
 268         for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++) {
 269                 struct route_table *table = lsdb->type[i].db;
 270                 struct route_node *rn;
 271
 272                 for (rn = route_top(table); rn; rn = route_next(rn))
 273                         if (rn->info)
 274                                 ospf_lsdb_delete(&nbr->db_sum, rn->info);
 275         }
 276 }
 277
 278
 279 /* The area link state database consists of the router-LSAs,
 280    network-LSAs and summary-LSAs contained in the area structure,
 281    along with the AS-external-LSAs contained in the global structure.
 282    AS-external-LSAs are omitted from a virtual neighbor's Database
 283    summary list.  AS-external-LSAs are omitted from the Database
 284    summary list if the area has been configured as a stub. */
 285 static int 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                 LSDB_LOOP (OPAQUE_LINK_LSDB(area), rn, lsa)
 306                         ospf_db_summary_add(nbr, lsa);
 307                 LSDB_LOOP (OPAQUE_AREA_LSDB(area), rn, lsa)
 308                         ospf_db_summary_add(nbr, lsa);
 309         }
 310
 311         if (CHECK_FLAG(nbr->options, OSPF_OPTION_NP)) {
 312                 LSDB_LOOP (NSSA_LSDB(area), rn, lsa)
 313                         ospf_db_summary_add(nbr, lsa);
 314         }
 315
 316         if (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 317             && area->external_routing == OSPF_AREA_DEFAULT)
 318                 LSDB_LOOP (EXTERNAL_LSDB(nbr->oi->ospf), rn, lsa)
 319                         ospf_db_summary_add(nbr, lsa);
 320
 321         if (CHECK_FLAG(nbr->options, OSPF_OPTION_O)
 322             && (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 323                 && area->external_routing == OSPF_AREA_DEFAULT))
 324                 LSDB_LOOP (OPAQUE_AS_LSDB(nbr->oi->ospf), rn, lsa)
 325                         ospf_db_summary_add(nbr, lsa);
 326
 327         return 0;
 328 }
 329
 330 static int 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 nsm_adj_ok(struct ospf_neighbor *nbr)
 343 {
 344         int next_state = nbr->state;
 345         int adj = nsm_should_adj(nbr);
 346
 347         if (nbr->state == NSM_TwoWay && adj == 1) {
 348                 next_state = NSM_ExStart;
 349
 350                 /* Send proactive ARP requests */
 351                 ospf_proactively_arp(nbr);
 352         } else if (nbr->state >= NSM_ExStart && adj == 0)
 353                 next_state = NSM_TwoWay;
 354
 355         return next_state;
 356 }
 357
 358 /* Clear adjacency related state for a neighbour, intended where nbr
 359  * transitions from > ExStart (i.e. a Full or forming adjacency)
 360  * to <= ExStart.
 361  */
 362 static void nsm_clear_adj(struct ospf_neighbor *nbr)
 363 {
 364         /* Clear Database Summary list. */
 365         if (!ospf_db_summary_isempty(nbr))
 366                 ospf_db_summary_clear(nbr);
 367
 368         /* Clear Link State Request list. */
 369         if (!ospf_ls_request_isempty(nbr))
 370                 ospf_ls_request_delete_all(nbr);
 371
 372         /* Clear Link State Retransmission list. */
 373         if (!ospf_ls_retransmit_isempty(nbr))
 374                 ospf_ls_retransmit_clear(nbr);
 375
 376         if (CHECK_FLAG(nbr->options, OSPF_OPTION_O))
 377                 UNSET_FLAG(nbr->options, OSPF_OPTION_O);
 378 }
 379
 380 static int nsm_kill_nbr(struct ospf_neighbor *nbr)
 381 {
 382         /* killing nbr_self is invalid */
 383         if (nbr == nbr->oi->nbr_self) {
 384                 assert(nbr != nbr->oi->nbr_self);
 385                 return 0;
 386         }
 387
 388         if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma != NULL) {
 389                 struct ospf_nbr_nbma *nbr_nbma = nbr->nbr_nbma;
 390
 391                 nbr_nbma->nbr = NULL;
 392                 nbr_nbma->state_change = nbr->state_change;
 393
 394                 nbr->nbr_nbma = NULL;
 395
 396                 OSPF_POLL_TIMER_ON(nbr_nbma->t_poll, ospf_poll_timer,
 397                                    nbr_nbma->v_poll);
 398
 399                 if (IS_DEBUG_OSPF(nsm, NSM_EVENTS))
 400                         zlog_debug(
 401                                 "NSM[%s:%pI4:%s]: Down (PollIntervalTimer scheduled)",
 402                                 IF_NAME(nbr->oi),
 403                                 &nbr->address.u.prefix4,
 404                                 ospf_get_name(nbr->oi->ospf));
 405         }
 406
 407         return 0;
 408 }
 409
 410 /* Neighbor State Machine */
 411 const struct {
 412         int (*func)(struct ospf_neighbor *);
 413         int next_state;
 414 } NSM[OSPF_NSM_STATE_MAX][OSPF_NSM_EVENT_MAX] = {
 415         {
 416                 /* DependUpon: dummy state. */
 417                 {NULL, NSM_DependUpon}, /* NoEvent           */
 418                 {NULL, NSM_DependUpon}, /* PacketReceived    */
 419                 {NULL, NSM_DependUpon}, /* Start             */
 420                 {NULL, NSM_DependUpon}, /* 2-WayReceived     */
 421                 {NULL, NSM_DependUpon}, /* NegotiationDone   */
 422                 {NULL, NSM_DependUpon}, /* ExchangeDone      */
 423                 {NULL, NSM_DependUpon}, /* BadLSReq          */
 424                 {NULL, NSM_DependUpon}, /* LoadingDone       */
 425                 {NULL, NSM_DependUpon}, /* AdjOK?            */
 426                 {NULL, NSM_DependUpon}, /* SeqNumberMismatch */
 427                 {NULL, NSM_DependUpon}, /* 1-WayReceived     */
 428                 {NULL, NSM_DependUpon}, /* KillNbr           */
 429                 {NULL, NSM_DependUpon}, /* InactivityTimer   */
 430                 {NULL, NSM_DependUpon}, /* LLDown            */
 431         },
 432         {
 433                 /* Deleted: dummy state. */
 434                 {NULL, NSM_Deleted}, /* NoEvent           */
 435                 {NULL, NSM_Deleted}, /* PacketReceived    */
 436                 {NULL, NSM_Deleted}, /* Start             */
 437                 {NULL, NSM_Deleted}, /* 2-WayReceived     */
 438                 {NULL, NSM_Deleted}, /* NegotiationDone   */
 439                 {NULL, NSM_Deleted}, /* ExchangeDone      */
 440                 {NULL, NSM_Deleted}, /* BadLSReq          */
 441                 {NULL, NSM_Deleted}, /* LoadingDone       */
 442                 {NULL, NSM_Deleted}, /* AdjOK?            */
 443                 {NULL, NSM_Deleted}, /* SeqNumberMismatch */
 444                 {NULL, NSM_Deleted}, /* 1-WayReceived     */
 445                 {NULL, NSM_Deleted}, /* KillNbr           */
 446                 {NULL, NSM_Deleted}, /* InactivityTimer   */
 447                 {NULL, NSM_Deleted}, /* LLDown            */
 448         },
 449         {
 450                 /* Down: */
 451                 {NULL, NSM_DependUpon},          /* NoEvent           */
 452                 {nsm_packet_received, NSM_Init}, /* PacketReceived    */
 453                 {nsm_start, NSM_Attempt},       /* Start             */
 454                 {NULL, NSM_Down},                /* 2-WayReceived     */
 455                 {NULL, NSM_Down},                /* NegotiationDone   */
 456                 {NULL, NSM_Down},                /* ExchangeDone      */
 457                 {NULL, NSM_Down},                /* BadLSReq          */
 458                 {NULL, NSM_Down},                /* LoadingDone       */
 459                 {NULL, NSM_Down},                /* AdjOK?            */
 460                 {NULL, NSM_Down},                /* SeqNumberMismatch */
 461                 {NULL, NSM_Down},                /* 1-WayReceived     */
 462                 {nsm_kill_nbr, NSM_Deleted},     /* KillNbr           */
 463                 {nsm_kill_nbr, NSM_Deleted},     /* InactivityTimer   */
 464                 {nsm_kill_nbr, NSM_Deleted},     /* LLDown            */
 465         },
 466         {
 467                 /* Attempt: */
 468                 {NULL, NSM_DependUpon},          /* NoEvent           */
 469                 {nsm_packet_received, NSM_Init}, /* PacketReceived    */
 470                 {NULL, NSM_Attempt},             /* Start             */
 471                 {NULL, NSM_Attempt},             /* 2-WayReceived     */
 472                 {NULL, NSM_Attempt},             /* NegotiationDone   */
 473                 {NULL, NSM_Attempt},             /* ExchangeDone      */
 474                 {NULL, NSM_Attempt},             /* BadLSReq          */
 475                 {NULL, NSM_Attempt},             /* LoadingDone       */
 476                 {NULL, NSM_Attempt},             /* AdjOK?            */
 477                 {NULL, NSM_Attempt},             /* SeqNumberMismatch */
 478                 {NULL, NSM_Attempt},             /* 1-WayReceived     */
 479                 {nsm_kill_nbr, NSM_Deleted},     /* KillNbr           */
 480                 {nsm_kill_nbr, NSM_Deleted},     /* InactivityTimer   */
 481                 {nsm_kill_nbr, NSM_Deleted},     /* LLDown            */
 482         },
 483         {
 484                 /* Init: */
 485                 {NULL, NSM_DependUpon},                /* NoEvent           */
 486                 {nsm_packet_received, NSM_Init},       /* PacketReceived    */
 487                 {NULL, NSM_Init},                      /* Start             */
 488                 {nsm_twoway_received, NSM_DependUpon}, /* 2-WayReceived     */
 489                 {NULL, NSM_Init},                      /* NegotiationDone   */
 490                 {NULL, NSM_Init},                      /* ExchangeDone      */
 491                 {NULL, NSM_Init},                      /* BadLSReq          */
 492                 {NULL, NSM_Init},                      /* LoadingDone       */
 493                 {NULL, NSM_Init},                      /* AdjOK?            */
 494                 {NULL, NSM_Init},                      /* SeqNumberMismatch */
 495                 {NULL, NSM_Init},                      /* 1-WayReceived     */
 496                 {nsm_kill_nbr, NSM_Deleted},       /* KillNbr           */
 497                 {nsm_kill_nbr, NSM_Deleted},       /* InactivityTimer   */
 498                 {nsm_kill_nbr, NSM_Deleted},       /* LLDown            */
 499         },
 500         {
 501                 /* 2-Way: */
 502                 {NULL, NSM_DependUpon},            /* NoEvent           */
 503                 {nsm_packet_received, NSM_TwoWay}, /* HelloReceived     */
 504                 {NULL, NSM_TwoWay},                /* Start             */
 505                 {NULL, NSM_TwoWay},                /* 2-WayReceived     */
 506                 {NULL, NSM_TwoWay},                /* NegotiationDone   */
 507                 {NULL, NSM_TwoWay},                /* ExchangeDone      */
 508                 {NULL, NSM_TwoWay},                /* BadLSReq          */
 509                 {NULL, NSM_TwoWay},                /* LoadingDone       */
 510                 {nsm_adj_ok, NSM_DependUpon},      /* AdjOK?            */
 511                 {NULL, NSM_TwoWay},                /* SeqNumberMismatch */
 512                 {NULL, NSM_Init},                  /* 1-WayReceived     */
 513                 {nsm_kill_nbr, NSM_Deleted},       /* KillNbr           */
 514                 {nsm_kill_nbr, NSM_Deleted},       /* InactivityTimer   */
 515                 {nsm_kill_nbr, NSM_Deleted},       /* LLDown            */
 516         },
 517         {
 518                 /* ExStart: */
 519                 {NULL, NSM_DependUpon},               /* NoEvent           */
 520                 {nsm_packet_received, NSM_ExStart},   /* PacaketReceived   */
 521                 {NULL, NSM_ExStart},                  /* Start             */
 522                 {NULL, NSM_ExStart},                  /* 2-WayReceived     */
 523                 {nsm_negotiation_done, NSM_Exchange}, /* NegotiationDone   */
 524                 {NULL, NSM_ExStart},                  /* ExchangeDone      */
 525                 {NULL, NSM_ExStart},                  /* BadLSReq          */
 526                 {NULL, NSM_ExStart},                  /* LoadingDone       */
 527                 {nsm_adj_ok, NSM_DependUpon},    /* AdjOK?            */
 528                 {NULL, NSM_ExStart},                  /* SeqNumberMismatch */
 529                 {NULL, NSM_Init},                     /* 1-WayReceived     */
 530                 {nsm_kill_nbr, NSM_Deleted},      /* KillNbr           */
 531                 {nsm_kill_nbr, NSM_Deleted},      /* InactivityTimer   */
 532                 {nsm_kill_nbr, NSM_Deleted},      /* LLDown            */
 533         },
 534         {
 535                 /* Exchange: */
 536                 {NULL, NSM_DependUpon},              /* NoEvent           */
 537                 {nsm_packet_received, NSM_Exchange}, /* PacketReceived    */
 538                 {NULL, NSM_Exchange},                /* Start             */
 539                 {NULL, NSM_Exchange},                /* 2-WayReceived     */
 540                 {NULL, NSM_Exchange},                /* NegotiationDone   */
 541                 {nsm_exchange_done, NSM_DependUpon}, /* ExchangeDone      */
 542                 {NULL, NSM_ExStart},                 /* BadLSReq          */
 543                 {NULL, NSM_Exchange},                /* LoadingDone       */
 544                 {nsm_adj_ok, NSM_DependUpon},   /* AdjOK?            */
 545                 {NULL, NSM_ExStart},                 /* SeqNumberMismatch */
 546                 {NULL, NSM_Init},                    /* 1-WayReceived     */
 547                 {nsm_kill_nbr, NSM_Deleted},     /* KillNbr           */
 548                 {nsm_kill_nbr, NSM_Deleted},     /* InactivityTimer   */
 549                 {nsm_kill_nbr, NSM_Deleted},     /* LLDown            */
 550         },
 551         {
 552                 /* Loading: */
 553                 {NULL, NSM_DependUpon},             /* NoEvent           */
 554                 {nsm_packet_received, NSM_Loading}, /* PacketReceived    */
 555                 {NULL, NSM_Loading},                /* Start             */
 556                 {NULL, NSM_Loading},                /* 2-WayReceived     */
 557                 {NULL, NSM_Loading},                /* NegotiationDone   */
 558                 {NULL, NSM_Loading},                /* ExchangeDone      */
 559                 {NULL, NSM_ExStart},                /* BadLSReq          */
 560                 {NULL, NSM_Full},                   /* LoadingDone       */
 561                 {nsm_adj_ok, NSM_DependUpon},       /* AdjOK?            */
 562                 {NULL, NSM_ExStart},                /* SeqNumberMismatch */
 563                 {NULL, NSM_Init},                   /* 1-WayReceived     */
 564                 {nsm_kill_nbr, NSM_Deleted},    /* KillNbr           */
 565                 {nsm_kill_nbr, NSM_Deleted},    /* InactivityTimer   */
 566                 {nsm_kill_nbr, NSM_Deleted},    /* LLDown            */
 567         },
 568         {
 569                 /* Full: */
 570                 {NULL, NSM_DependUpon},          /* NoEvent           */
 571                 {nsm_packet_received, NSM_Full}, /* PacketReceived    */
 572                 {NULL, NSM_Full},                /* Start             */
 573                 {NULL, NSM_Full},                /* 2-WayReceived     */
 574                 {NULL, NSM_Full},                /* NegotiationDone   */
 575                 {NULL, NSM_Full},                /* ExchangeDone      */
 576                 {NULL, NSM_ExStart},             /* BadLSReq          */
 577                 {NULL, NSM_Full},                /* LoadingDone       */
 578                 {nsm_adj_ok, NSM_DependUpon},    /* AdjOK?            */
 579                 {NULL, NSM_ExStart},             /* SeqNumberMismatch */
 580                 {NULL, NSM_Init},                /* 1-WayReceived     */
 581                 {nsm_kill_nbr, NSM_Deleted},     /* KillNbr           */
 582                 {nsm_kill_nbr, NSM_Deleted},     /* InactivityTimer   */
 583                 {nsm_kill_nbr, NSM_Deleted},     /* LLDown            */
 584         },
 585 };
 586
 587 static const char *const ospf_nsm_event_str[] = {
 588         "NoEvent",         "PacketReceived",  "Start",
 589         "2-WayReceived",     "NegotiationDone", "ExchangeDone",
 590         "BadLSReq",       "LoadingDone",     "AdjOK?",
 591         "SeqNumberMismatch", "1-WayReceived",   "KillNbr",
 592         "InactivityTimer",   "LLDown",
 593 };
 594
 595 static void nsm_notice_state_change(struct ospf_neighbor *nbr, int next_state,
 596                                     int event)
 597 {
 598         /* Logging change of status. */
 599         if (IS_DEBUG_OSPF(nsm, NSM_STATUS))
 600                 zlog_debug("NSM[%s:%pI4:%s]: State change %s -> %s (%s)",
 601                            IF_NAME(nbr->oi), &nbr->router_id,
 602                            ospf_get_name(nbr->oi->ospf),
 603                            lookup_msg(ospf_nsm_state_msg, nbr->state, NULL),
 604                            lookup_msg(ospf_nsm_state_msg, next_state, NULL),
 605                            ospf_nsm_event_str[event]);
 606
 607         /* Optionally notify about adjacency changes */
 608         if (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_CHANGES)
 609             && (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL)
 610                 || (next_state == NSM_Full) || (next_state < nbr->state)))
 611                 zlog_notice("AdjChg: Nbr %pI4(%s) on %s: %s -> %s (%s)",
 612                             &nbr->router_id,
 613                             ospf_get_name(nbr->oi->ospf), IF_NAME(nbr->oi),
 614                             lookup_msg(ospf_nsm_state_msg, nbr->state, NULL),
 615                             lookup_msg(ospf_nsm_state_msg, next_state, NULL),
 616                             ospf_nsm_event_str[event]);
 617
 618         /* Advance in NSM */
 619         if (next_state > nbr->state)
 620                 monotime(&nbr->ts_last_progress);
 621         else /* regression in NSM */
 622         {
 623                 monotime(&nbr->ts_last_regress);
 624                 nbr->last_regress_str = ospf_nsm_event_str[event];
 625         }
 626 }
 627
 628 static void nsm_change_state(struct ospf_neighbor *nbr, int state)
 629 {
 630         struct ospf_interface *oi = nbr->oi;
 631         struct ospf_area *vl_area = NULL;
 632         uint8_t old_state;
 633
 634         /* Preserve old status. */
 635         old_state = nbr->state;
 636
 637         /* Change to new status. */
 638         nbr->state = state;
 639
 640         /* Statistics. */
 641         nbr->state_change++;
 642
 643         if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
 644                 vl_area = ospf_area_lookup_by_area_id(oi->ospf,
 645                                                       oi->vl_data->vl_area_id);
 646
 647         /* Generate NeighborChange ISM event.
 648          *
 649          * In response to NeighborChange, DR election is rerun. The information
 650          * from the election process is required by the router-lsa construction.
 651          *
 652          * Therefore, trigger the event prior to refreshing the LSAs. */
 653         switch (oi->state) {
 654         case ISM_DROther:
 655         case ISM_Backup:
 656         case ISM_DR:
 657                 if ((old_state < NSM_TwoWay && state >= NSM_TwoWay)
 658                     || (old_state >= NSM_TwoWay && state < NSM_TwoWay))
 659                         OSPF_ISM_EVENT_EXECUTE(oi, ISM_NeighborChange);
 660                 break;
 661         default:
 662                 /* ISM_PointToPoint -> ISM_Down, ISM_Loopback -> ISM_Down, etc.
 663                  */
 664                 break;
 665         }
 666
 667         /* One of the neighboring routers changes to/from the FULL state. */
 668         if ((old_state != NSM_Full && state == NSM_Full)
 669             || (old_state == NSM_Full && state != NSM_Full)) {
 670                 if (state == NSM_Full) {
 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 == 1)
 678                                         ospf_schedule_abr_task(oi->ospf);
 679                 } else {
 680                         oi->full_nbrs--;
 681                         oi->area->full_nbrs--;
 682
 683                         ospf_check_abr_status(oi->ospf);
 684
 685                         if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 686                                 if (vl_area->full_vls > 0)
 687                                         if (--vl_area->full_vls == 0)
 688                                                 ospf_schedule_abr_task(
 689                                                         oi->ospf);
 690                 }
 691
 692                 if (CHECK_FLAG(oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL))
 693                         zlog_info(
 694                                 "%s:[%pI4:%s], %s -> %s): scheduling new router-LSA origination",
 695                                 __func__, &nbr->router_id,
 696                                 ospf_get_name(oi->ospf),
 697                                 lookup_msg(ospf_nsm_state_msg, old_state, NULL),
 698                                 lookup_msg(ospf_nsm_state_msg, state, NULL));
 699
 700                 /* Dont originate router LSA if the current
 701                  * router is acting as a HELPER for this neighbour.
 702                  */
 703                 if (!OSPF_GR_IS_ACTIVE_HELPER(nbr))
 704                         ospf_router_lsa_update_area(oi->area);
 705
 706                 if (oi->type == OSPF_IFTYPE_VIRTUALLINK) {
 707                         vl_area = ospf_area_lookup_by_area_id(
 708                                 oi->ospf, oi->vl_data->vl_area_id);
 709
 710                         if (vl_area)
 711                                 ospf_router_lsa_update_area(vl_area);
 712                 }
 713
 714                 /* Dont originate/flush network LSA if the current
 715                  * router is acting as a HELPER for this neighbour.
 716                  */
 717                 if (!OSPF_GR_IS_ACTIVE_HELPER(nbr)) {
 718                         /* Originate network-LSA. */
 719                         if (oi->state == ISM_DR) {
 720                                 if (oi->network_lsa_self
 721                                     && oi->full_nbrs == 0) {
 722                                         ospf_lsa_flush_area(
 723                                                 oi->network_lsa_self, oi->area);
 724                                         ospf_lsa_unlock(&oi->network_lsa_self);
 725                                         oi->network_lsa_self = NULL;
 726                                 } else
 727                                         ospf_network_lsa_update(oi);
 728                         }
 729                 }
 730         }
 731
 732         ospf_opaque_nsm_change(nbr, old_state);
 733
 734         /* State changes from > ExStart to <= ExStart should clear any Exchange
 735          * or Full/LSA Update related lists and state.
 736          * Potential causal events: BadLSReq, SeqNumberMismatch, AdjOK?
 737          */
 738         if ((old_state > NSM_ExStart) && (state <= NSM_ExStart))
 739                 nsm_clear_adj(nbr);
 740
 741         /* Start DD exchange protocol */
 742         if (state == NSM_ExStart) {
 743                 if (nbr->dd_seqnum == 0)
 744                         nbr->dd_seqnum = (uint32_t)frr_weak_random();
 745                 else
 746                         nbr->dd_seqnum++;
 747
 748                 nbr->dd_flags =
 749                         OSPF_DD_FLAG_I | OSPF_DD_FLAG_M | OSPF_DD_FLAG_MS;
 750                 if (CHECK_FLAG(oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL))
 751                         zlog_info(
 752                                 "%s: Initializing [DD]: %pI4 with seqnum:%x , flags:%x",
 753                                 (oi->ospf->name) ? oi->ospf->name
 754                                                  : VRF_DEFAULT_NAME,
 755                                 &nbr->router_id, nbr->dd_seqnum,
 756                                 nbr->dd_flags);
 757                 ospf_db_desc_send(nbr);
 758         }
 759
 760         /* clear cryptographic sequence number */
 761         if (state == NSM_Down)
 762                 nbr->crypt_seqnum = 0;
 763
 764         if (nbr->bfd_session)
 765                 ospf_bfd_trigger_event(nbr, old_state, state);
 766
 767         /* Preserve old status? */
 768 }
 769
 770 /* Execute NSM event process. */
 771 int ospf_nsm_event(struct thread *thread)
 772 {
 773         int event;
 774         int next_state;
 775         struct ospf_neighbor *nbr;
 776
 777         nbr = THREAD_ARG(thread);
 778         event = THREAD_VAL(thread);
 779
 780         if (IS_DEBUG_OSPF(nsm, NSM_EVENTS))
 781                 zlog_debug("NSM[%s:%pI4:%s]: %s (%s)", IF_NAME(nbr->oi),
 782                            &nbr->router_id,
 783                            ospf_get_name(nbr->oi->ospf),
 784                            lookup_msg(ospf_nsm_state_msg, nbr->state, NULL),
 785                            ospf_nsm_event_str[event]);
 786
 787         next_state = NSM[nbr->state][event].next_state;
 788
 789         /* Call function. */
 790         if (NSM[nbr->state][event].func != NULL) {
 791                 int func_state = (*(NSM[nbr->state][event].func))(nbr);
 792
 793                 if (NSM[nbr->state][event].next_state == NSM_DependUpon)
 794                         next_state = func_state;
 795                 else if (func_state) {
 796                         /* There's a mismatch between the FSM tables and what an
 797                          * FSM
 798                          * action/state-change function returned. State changes
 799                          * which
 800                          * do not have conditional/DependUpon next-states should
 801                          * not
 802                          * try set next_state.
 803                          */
 804                         flog_err(
 805                                 EC_OSPF_FSM_INVALID_STATE,
 806                                 "NSM[%s:%pI4:%s]: %s (%s): Warning: action tried to change next_state to %s",
 807                                 IF_NAME(nbr->oi), &nbr->router_id,
 808                                 ospf_get_name(nbr->oi->ospf),
 809                                 lookup_msg(ospf_nsm_state_msg, nbr->state,
 810                                            NULL),
 811                                 ospf_nsm_event_str[event],
 812                                 lookup_msg(ospf_nsm_state_msg, func_state,
 813                                            NULL));
 814                 }
 815         }
 816
 817         assert(next_state != NSM_DependUpon);
 818
 819         /* If state is changed. */
 820         if (next_state != nbr->state) {
 821                 int old_state = nbr->state;
 822
 823                 nsm_notice_state_change(nbr, next_state, event);
 824                 nsm_change_state(nbr, next_state);
 825
 826                 hook_call(ospf_nsm_change, nbr, next_state, old_state);
 827         }
 828
 829         /* Make sure timer is set. */
 830         nsm_timer_set(nbr);
 831
 832         /* When event is NSM_KillNbr, InactivityTimer or LLDown, the neighbor
 833          * is deleted.
 834          *
 835          * Rather than encode knowledge here of which events lead to NBR
 836          * delete, we take our cue from the NSM table, via the dummy
 837          * 'Deleted' neighbour state.
 838          */
 839         if (nbr->state == NSM_Deleted)
 840                 ospf_nbr_delete(nbr);
 841
 842         return 0;
 843 }
 844
 845 /* Check loading state. */
 846 void ospf_check_nbr_loading(struct ospf_neighbor *nbr)
 847 {
 848         if (nbr->state == NSM_Loading) {
 849                 if (ospf_ls_request_isempty(nbr))
 850                         OSPF_NSM_EVENT_SCHEDULE(nbr, NSM_LoadingDone);
 851                 else if (nbr->ls_req_last == NULL)
 852                         ospf_ls_req_event(nbr);
 853         }
 854 }