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_gr.h"
  53 #include "ospfd/ospf_errors.h"
  54
  55 DEFINE_HOOK(ospf_nsm_change,
  56             (struct ospf_neighbor * on, int state, int oldstate),
  57             (on, state, oldstate));
  58
  59 static void nsm_clear_adj(struct ospf_neighbor *);
  60
  61 /* OSPF NSM Timer functions. */
  62 static int ospf_inactivity_timer(struct thread *thread)
  63 {
  64         struct ospf_neighbor *nbr;
  65
  66         nbr = THREAD_ARG(thread);
  67         nbr->t_inactivity = NULL;
  68
  69         if (IS_DEBUG_OSPF(nsm, NSM_TIMERS))
  70                 zlog_debug("NSM[%s:%pI4:%s]: Timer (Inactivity timer expire)",
  71                            IF_NAME(nbr->oi), &nbr->router_id,
  72                            ospf_get_name(nbr->oi->ospf));
  73
  74         /* Dont trigger NSM_InactivityTimer event , if the current
  75          * router acting as HELPER for this neighbour.
  76          */
  77         if (!OSPF_GR_IS_ACTIVE_HELPER(nbr))
  78                 OSPF_NSM_EVENT_SCHEDULE(nbr, NSM_InactivityTimer);
  79         else if (IS_DEBUG_OSPF_GR)
  80                 zlog_debug(
  81                         "%s, Acting as HELPER for this neighbour, So inactivitytimer event will not be fired.",
  82                         __func__);
  83
  84         return 0;
  85 }
  86
  87 static int ospf_db_desc_timer(struct thread *thread)
  88 {
  89         struct ospf_neighbor *nbr;
  90
  91         nbr = THREAD_ARG(thread);
  92         nbr->t_db_desc = NULL;
  93
  94         if (IS_DEBUG_OSPF(nsm, NSM_TIMERS))
  95                 zlog_debug("NSM[%s:%pI4:%s]: Timer (DD Retransmit timer expire)",
  96                            IF_NAME(nbr->oi), &nbr->src,
  97                            ospf_get_name(nbr->oi->ospf));
  98
  99         /* resent last send DD packet. */
 100         assert(nbr->last_send);
 101         ospf_db_desc_resend(nbr);
 102
 103         /* DD Retransmit timer set. */
 104         OSPF_NSM_TIMER_ON(nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
 105
 106         return 0;
 107 }
 108
 109 /* Hook function called after ospf NSM event is occurred.
 110  *
 111  * Set/clear any timers whose condition is implicit to the neighbour
 112  * state. There may be other timers which are set/unset according to other
 113  * state.
 114  *
 115  * We rely on this function to properly clear timers in lower states,
 116  * particularly before deleting a neighbour.
 117  */
 118 static void nsm_timer_set(struct ospf_neighbor *nbr)
 119 {
 120         switch (nbr->state) {
 121         case NSM_Deleted:
 122         case NSM_Down:
 123                 OSPF_NSM_TIMER_OFF(nbr->t_inactivity);
 124                 OSPF_NSM_TIMER_OFF(nbr->t_hello_reply);
 125         /* fallthru */
 126         case NSM_Attempt:
 127         case NSM_Init:
 128         case NSM_TwoWay:
 129                 OSPF_NSM_TIMER_OFF(nbr->t_db_desc);
 130                 OSPF_NSM_TIMER_OFF(nbr->t_ls_upd);
 131                 OSPF_NSM_TIMER_OFF(nbr->t_ls_req);
 132                 break;
 133         case NSM_ExStart:
 134                 OSPF_NSM_TIMER_ON(nbr->t_db_desc, ospf_db_desc_timer,
 135                                   nbr->v_db_desc);
 136                 OSPF_NSM_TIMER_OFF(nbr->t_ls_upd);
 137                 OSPF_NSM_TIMER_OFF(nbr->t_ls_req);
 138                 break;
 139         case NSM_Exchange:
 140                 OSPF_NSM_TIMER_ON(nbr->t_ls_upd, ospf_ls_upd_timer,
 141                                   nbr->v_ls_upd);
 142                 if (!IS_SET_DD_MS(nbr->dd_flags))
 143                         OSPF_NSM_TIMER_OFF(nbr->t_db_desc);
 144                 break;
 145         case NSM_Loading:
 146         case NSM_Full:
 147         default:
 148                 OSPF_NSM_TIMER_OFF(nbr->t_db_desc);
 149                 break;
 150         }
 151 }
 152
 153 /* 10.4 of RFC2328, indicate whether an adjacency is appropriate with
 154  * the given neighbour
 155  */
 156 int nsm_should_adj(struct ospf_neighbor *nbr)
 157 {
 158         struct ospf_interface *oi = nbr->oi;
 159
 160         /* These network types must always form adjacencies. */
 161         if (oi->type == OSPF_IFTYPE_POINTOPOINT
 162             || oi->type == OSPF_IFTYPE_POINTOMULTIPOINT
 163             || oi->type == OSPF_IFTYPE_VIRTUALLINK
 164             /* Router itself is the DRouter or the BDRouter. */
 165             || IPV4_ADDR_SAME(&oi->address->u.prefix4, &DR(oi))
 166             || IPV4_ADDR_SAME(&oi->address->u.prefix4, &BDR(oi))
 167             /* Neighboring Router is the DRouter or the BDRouter. */
 168             || IPV4_ADDR_SAME(&nbr->address.u.prefix4, &DR(oi))
 169             || IPV4_ADDR_SAME(&nbr->address.u.prefix4, &BDR(oi)))
 170                 return 1;
 171
 172         return 0;
 173 }
 174
 175 /* OSPF NSM functions. */
 176 static int nsm_packet_received(struct ospf_neighbor *nbr)
 177 {
 178         /* Start or Restart Inactivity Timer. */
 179         OSPF_NSM_TIMER_OFF(nbr->t_inactivity);
 180
 181         OSPF_NSM_TIMER_ON(nbr->t_inactivity, ospf_inactivity_timer,
 182                           nbr->v_inactivity);
 183
 184         if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma)
 185                 OSPF_POLL_TIMER_OFF(nbr->nbr_nbma->t_poll);
 186
 187         /* Send proactive ARP requests */
 188         if (nbr->state < NSM_Exchange)
 189                 ospf_proactively_arp(nbr);
 190
 191         return 0;
 192 }
 193
 194 static int nsm_start(struct ospf_neighbor *nbr)
 195 {
 196         if (nbr->nbr_nbma)
 197                 OSPF_POLL_TIMER_OFF(nbr->nbr_nbma->t_poll);
 198
 199         OSPF_NSM_TIMER_OFF(nbr->t_inactivity);
 200
 201         OSPF_NSM_TIMER_ON(nbr->t_inactivity, ospf_inactivity_timer,
 202                           nbr->v_inactivity);
 203
 204         /* Send proactive ARP requests */
 205         ospf_proactively_arp(nbr);
 206
 207         return 0;
 208 }
 209
 210 static int nsm_twoway_received(struct ospf_neighbor *nbr)
 211 {
 212         int adj = nsm_should_adj(nbr);
 213
 214         /* Send proactive ARP requests */
 215         if (adj)
 216                 ospf_proactively_arp(nbr);
 217
 218         return (adj ? NSM_ExStart : NSM_TwoWay);
 219 }
 220
 221 int ospf_db_summary_count(struct ospf_neighbor *nbr)
 222 {
 223         return ospf_lsdb_count_all(&nbr->db_sum);
 224 }
 225
 226 int ospf_db_summary_isempty(struct ospf_neighbor *nbr)
 227 {
 228         return ospf_lsdb_isempty(&nbr->db_sum);
 229 }
 230
 231 static int ospf_db_summary_add(struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
 232 {
 233         switch (lsa->data->type) {
 234         case OSPF_OPAQUE_LINK_LSA:
 235                 /* Exclude type-9 LSAs that does not have the same "oi" with
 236                  * "nbr". */
 237                 if (ospf_if_exists(lsa->oi) != nbr->oi)
 238                         return 0;
 239                 break;
 240         case OSPF_OPAQUE_AREA_LSA:
 241                 /*
 242                  * It is assured by the caller function "nsm_negotiation_done()"
 243                  * that every given LSA belongs to the same area with "nbr".
 244                  */
 245                 break;
 246         case OSPF_OPAQUE_AS_LSA:
 247         default:
 248                 break;
 249         }
 250
 251         /* Stay away from any Local Translated Type-7 LSAs */
 252         if (CHECK_FLAG(lsa->flags, OSPF_LSA_LOCAL_XLT))
 253                 return 0;
 254
 255         if (IS_LSA_MAXAGE(lsa))
 256                 ospf_ls_retransmit_add(nbr, lsa);
 257         else
 258                 ospf_lsdb_add(&nbr->db_sum, lsa);
 259
 260         return 0;
 261 }
 262
 263 void ospf_db_summary_clear(struct ospf_neighbor *nbr)
 264 {
 265         struct ospf_lsdb *lsdb;
 266         int i;
 267
 268         lsdb = &nbr->db_sum;
 269         for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++) {
 270                 struct route_table *table = lsdb->type[i].db;
 271                 struct route_node *rn;
 272
 273                 for (rn = route_top(table); rn; rn = route_next(rn))
 274                         if (rn->info)
 275                                 ospf_lsdb_delete(&nbr->db_sum, rn->info);
 276         }
 277 }
 278
 279
 280 /* The area link state database consists of the router-LSAs,
 281    network-LSAs and summary-LSAs contained in the area structure,
 282    along with the AS-external-LSAs contained in the global structure.
 283    AS-external-LSAs are omitted from a virtual neighbor's Database
 284    summary list.  AS-external-LSAs are omitted from the Database
 285    summary list if the area has been configured as a stub. */
 286 static int nsm_negotiation_done(struct ospf_neighbor *nbr)
 287 {
 288         struct ospf_area *area = nbr->oi->area;
 289         struct ospf_lsa *lsa;
 290         struct route_node *rn;
 291
 292         /* Send proactive ARP requests */
 293         ospf_proactively_arp(nbr);
 294
 295         LSDB_LOOP (ROUTER_LSDB(area), rn, lsa)
 296                 ospf_db_summary_add(nbr, lsa);
 297         LSDB_LOOP (NETWORK_LSDB(area), rn, lsa)
 298                 ospf_db_summary_add(nbr, lsa);
 299         LSDB_LOOP (SUMMARY_LSDB(area), rn, lsa)
 300                 ospf_db_summary_add(nbr, lsa);
 301         LSDB_LOOP (ASBR_SUMMARY_LSDB(area), rn, lsa)
 302                 ospf_db_summary_add(nbr, lsa);
 303
 304         /* Process only if the neighbor is opaque capable. */
 305         if (CHECK_FLAG(nbr->options, OSPF_OPTION_O)) {
 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                 LSDB_LOOP (NSSA_LSDB(area), rn, lsa)
 314                         ospf_db_summary_add(nbr, lsa);
 315         }
 316
 317         if (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 318             && area->external_routing == OSPF_AREA_DEFAULT)
 319                 LSDB_LOOP (EXTERNAL_LSDB(nbr->oi->ospf), rn, lsa)
 320                         ospf_db_summary_add(nbr, lsa);
 321
 322         if (CHECK_FLAG(nbr->options, OSPF_OPTION_O)
 323             && (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 324                 && area->external_routing == OSPF_AREA_DEFAULT))
 325                 LSDB_LOOP (OPAQUE_AS_LSDB(nbr->oi->ospf), rn, lsa)
 326                         ospf_db_summary_add(nbr, lsa);
 327
 328         return 0;
 329 }
 330
 331 static int nsm_exchange_done(struct ospf_neighbor *nbr)
 332 {
 333         if (ospf_ls_request_isempty(nbr))
 334                 return NSM_Full;
 335
 336         /* Send Link State Request. */
 337         if (nbr->t_ls_req == NULL)
 338                 ospf_ls_req_send(nbr);
 339
 340         return NSM_Loading;
 341 }
 342
 343 static int nsm_adj_ok(struct ospf_neighbor *nbr)
 344 {
 345         int next_state = nbr->state;
 346         int adj = nsm_should_adj(nbr);
 347
 348         if (nbr->state == NSM_TwoWay && adj == 1) {
 349                 next_state = NSM_ExStart;
 350
 351                 /* Send proactive ARP requests */
 352                 ospf_proactively_arp(nbr);
 353         } else if (nbr->state >= NSM_ExStart && adj == 0)
 354                 next_state = NSM_TwoWay;
 355
 356         return next_state;
 357 }
 358
 359 /* Clear adjacency related state for a neighbour, intended where nbr
 360  * transitions from > ExStart (i.e. a Full or forming adjacency)
 361  * to <= ExStart.
 362  */
 363 static void nsm_clear_adj(struct ospf_neighbor *nbr)
 364 {
 365         /* Clear Database Summary list. */
 366         if (!ospf_db_summary_isempty(nbr))
 367                 ospf_db_summary_clear(nbr);
 368
 369         /* Clear Link State Request list. */
 370         if (!ospf_ls_request_isempty(nbr))
 371                 ospf_ls_request_delete_all(nbr);
 372
 373         /* Clear Link State Retransmission list. */
 374         if (!ospf_ls_retransmit_isempty(nbr))
 375                 ospf_ls_retransmit_clear(nbr);
 376
 377         if (CHECK_FLAG(nbr->options, OSPF_OPTION_O))
 378                 UNSET_FLAG(nbr->options, OSPF_OPTION_O);
 379 }
 380
 381 static int nsm_kill_nbr(struct ospf_neighbor *nbr)
 382 {
 383         /* killing nbr_self is invalid */
 384         if (nbr == nbr->oi->nbr_self) {
 385                 assert(nbr != nbr->oi->nbr_self);
 386                 return 0;
 387         }
 388
 389         if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma != NULL) {
 390                 struct ospf_nbr_nbma *nbr_nbma = nbr->nbr_nbma;
 391
 392                 nbr_nbma->nbr = NULL;
 393                 nbr_nbma->state_change = nbr->state_change;
 394
 395                 nbr->nbr_nbma = NULL;
 396
 397                 OSPF_POLL_TIMER_ON(nbr_nbma->t_poll, ospf_poll_timer,
 398                                    nbr_nbma->v_poll);
 399
 400                 if (IS_DEBUG_OSPF(nsm, NSM_EVENTS))
 401                         zlog_debug(
 402                                 "NSM[%s:%pI4:%s]: Down (PollIntervalTimer scheduled)",
 403                                 IF_NAME(nbr->oi),
 404                                 &nbr->address.u.prefix4,
 405                                 ospf_get_name(nbr->oi->ospf));
 406         }
 407
 408         return 0;
 409 }
 410
 411 /* Neighbor State Machine */
 412 const struct {
 413         int (*func)(struct ospf_neighbor *);
 414         int next_state;
 415 } NSM[OSPF_NSM_STATE_MAX][OSPF_NSM_EVENT_MAX] = {
 416         {
 417                 /* DependUpon: dummy state. */
 418                 {NULL, NSM_DependUpon}, /* NoEvent           */
 419                 {NULL, NSM_DependUpon}, /* PacketReceived    */
 420                 {NULL, NSM_DependUpon}, /* Start             */
 421                 {NULL, NSM_DependUpon}, /* 2-WayReceived     */
 422                 {NULL, NSM_DependUpon}, /* NegotiationDone   */
 423                 {NULL, NSM_DependUpon}, /* ExchangeDone      */
 424                 {NULL, NSM_DependUpon}, /* BadLSReq          */
 425                 {NULL, NSM_DependUpon}, /* LoadingDone       */
 426                 {NULL, NSM_DependUpon}, /* AdjOK?            */
 427                 {NULL, NSM_DependUpon}, /* SeqNumberMismatch */
 428                 {NULL, NSM_DependUpon}, /* 1-WayReceived     */
 429                 {NULL, NSM_DependUpon}, /* KillNbr           */
 430                 {NULL, NSM_DependUpon}, /* InactivityTimer   */
 431                 {NULL, NSM_DependUpon}, /* LLDown            */
 432         },
 433         {
 434                 /* Deleted: dummy state. */
 435                 {NULL, NSM_Deleted}, /* NoEvent           */
 436                 {NULL, NSM_Deleted}, /* PacketReceived    */
 437                 {NULL, NSM_Deleted}, /* Start             */
 438                 {NULL, NSM_Deleted}, /* 2-WayReceived     */
 439                 {NULL, NSM_Deleted}, /* NegotiationDone   */
 440                 {NULL, NSM_Deleted}, /* ExchangeDone      */
 441                 {NULL, NSM_Deleted}, /* BadLSReq          */
 442                 {NULL, NSM_Deleted}, /* LoadingDone       */
 443                 {NULL, NSM_Deleted}, /* AdjOK?            */
 444                 {NULL, NSM_Deleted}, /* SeqNumberMismatch */
 445                 {NULL, NSM_Deleted}, /* 1-WayReceived     */
 446                 {NULL, NSM_Deleted}, /* KillNbr           */
 447                 {NULL, NSM_Deleted}, /* InactivityTimer   */
 448                 {NULL, NSM_Deleted}, /* LLDown            */
 449         },
 450         {
 451                 /* Down: */
 452                 {NULL, NSM_DependUpon},          /* NoEvent           */
 453                 {nsm_packet_received, NSM_Init}, /* PacketReceived    */
 454                 {nsm_start, NSM_Attempt},       /* Start             */
 455                 {NULL, NSM_Down},                /* 2-WayReceived     */
 456                 {NULL, NSM_Down},                /* NegotiationDone   */
 457                 {NULL, NSM_Down},                /* ExchangeDone      */
 458                 {NULL, NSM_Down},                /* BadLSReq          */
 459                 {NULL, NSM_Down},                /* LoadingDone       */
 460                 {NULL, NSM_Down},                /* AdjOK?            */
 461                 {NULL, NSM_Down},                /* SeqNumberMismatch */
 462                 {NULL, NSM_Down},                /* 1-WayReceived     */
 463                 {nsm_kill_nbr, NSM_Deleted},     /* KillNbr           */
 464                 {nsm_kill_nbr, NSM_Deleted},     /* InactivityTimer   */
 465                 {nsm_kill_nbr, NSM_Deleted},     /* LLDown            */
 466         },
 467         {
 468                 /* Attempt: */
 469                 {NULL, NSM_DependUpon},          /* NoEvent           */
 470                 {nsm_packet_received, NSM_Init}, /* PacketReceived    */
 471                 {NULL, NSM_Attempt},             /* Start             */
 472                 {NULL, NSM_Attempt},             /* 2-WayReceived     */
 473                 {NULL, NSM_Attempt},             /* NegotiationDone   */
 474                 {NULL, NSM_Attempt},             /* ExchangeDone      */
 475                 {NULL, NSM_Attempt},             /* BadLSReq          */
 476                 {NULL, NSM_Attempt},             /* LoadingDone       */
 477                 {NULL, NSM_Attempt},             /* AdjOK?            */
 478                 {NULL, NSM_Attempt},             /* SeqNumberMismatch */
 479                 {NULL, NSM_Attempt},             /* 1-WayReceived     */
 480                 {nsm_kill_nbr, NSM_Deleted},     /* KillNbr           */
 481                 {nsm_kill_nbr, NSM_Deleted},     /* InactivityTimer   */
 482                 {nsm_kill_nbr, NSM_Deleted},     /* LLDown            */
 483         },
 484         {
 485                 /* Init: */
 486                 {NULL, NSM_DependUpon},                /* NoEvent           */
 487                 {nsm_packet_received, NSM_Init},       /* PacketReceived    */
 488                 {NULL, NSM_Init},                      /* Start             */
 489                 {nsm_twoway_received, NSM_DependUpon}, /* 2-WayReceived     */
 490                 {NULL, NSM_Init},                      /* NegotiationDone   */
 491                 {NULL, NSM_Init},                      /* ExchangeDone      */
 492                 {NULL, NSM_Init},                      /* BadLSReq          */
 493                 {NULL, NSM_Init},                      /* LoadingDone       */
 494                 {NULL, NSM_Init},                      /* AdjOK?            */
 495                 {NULL, NSM_Init},                      /* SeqNumberMismatch */
 496                 {NULL, NSM_Init},                      /* 1-WayReceived     */
 497                 {nsm_kill_nbr, NSM_Deleted},       /* KillNbr           */
 498                 {nsm_kill_nbr, NSM_Deleted},       /* InactivityTimer   */
 499                 {nsm_kill_nbr, NSM_Deleted},       /* LLDown            */
 500         },
 501         {
 502                 /* 2-Way: */
 503                 {NULL, NSM_DependUpon},            /* NoEvent           */
 504                 {nsm_packet_received, NSM_TwoWay}, /* HelloReceived     */
 505                 {NULL, NSM_TwoWay},                /* Start             */
 506                 {NULL, NSM_TwoWay},                /* 2-WayReceived     */
 507                 {NULL, NSM_TwoWay},                /* NegotiationDone   */
 508                 {NULL, NSM_TwoWay},                /* ExchangeDone      */
 509                 {NULL, NSM_TwoWay},                /* BadLSReq          */
 510                 {NULL, NSM_TwoWay},                /* LoadingDone       */
 511                 {nsm_adj_ok, NSM_DependUpon},      /* AdjOK?            */
 512                 {NULL, NSM_TwoWay},                /* SeqNumberMismatch */
 513                 {NULL, NSM_Init},                  /* 1-WayReceived     */
 514                 {nsm_kill_nbr, NSM_Deleted},       /* KillNbr           */
 515                 {nsm_kill_nbr, NSM_Deleted},       /* InactivityTimer   */
 516                 {nsm_kill_nbr, NSM_Deleted},       /* LLDown            */
 517         },
 518         {
 519                 /* ExStart: */
 520                 {NULL, NSM_DependUpon},               /* NoEvent           */
 521                 {nsm_packet_received, NSM_ExStart},   /* PacaketReceived   */
 522                 {NULL, NSM_ExStart},                  /* Start             */
 523                 {NULL, NSM_ExStart},                  /* 2-WayReceived     */
 524                 {nsm_negotiation_done, NSM_Exchange}, /* NegotiationDone   */
 525                 {NULL, NSM_ExStart},                  /* ExchangeDone      */
 526                 {NULL, NSM_ExStart},                  /* BadLSReq          */
 527                 {NULL, NSM_ExStart},                  /* LoadingDone       */
 528                 {nsm_adj_ok, NSM_DependUpon},    /* AdjOK?            */
 529                 {NULL, NSM_ExStart},                  /* SeqNumberMismatch */
 530                 {NULL, NSM_Init},                     /* 1-WayReceived     */
 531                 {nsm_kill_nbr, NSM_Deleted},      /* KillNbr           */
 532                 {nsm_kill_nbr, NSM_Deleted},      /* InactivityTimer   */
 533                 {nsm_kill_nbr, NSM_Deleted},      /* LLDown            */
 534         },
 535         {
 536                 /* Exchange: */
 537                 {NULL, NSM_DependUpon},              /* NoEvent           */
 538                 {nsm_packet_received, NSM_Exchange}, /* PacketReceived    */
 539                 {NULL, NSM_Exchange},                /* Start             */
 540                 {NULL, NSM_Exchange},                /* 2-WayReceived     */
 541                 {NULL, NSM_Exchange},                /* NegotiationDone   */
 542                 {nsm_exchange_done, NSM_DependUpon}, /* ExchangeDone      */
 543                 {NULL, NSM_ExStart},                 /* BadLSReq          */
 544                 {NULL, NSM_Exchange},                /* LoadingDone       */
 545                 {nsm_adj_ok, NSM_DependUpon},   /* AdjOK?            */
 546                 {NULL, NSM_ExStart},                 /* SeqNumberMismatch */
 547                 {NULL, NSM_Init},                    /* 1-WayReceived     */
 548                 {nsm_kill_nbr, NSM_Deleted},     /* KillNbr           */
 549                 {nsm_kill_nbr, NSM_Deleted},     /* InactivityTimer   */
 550                 {nsm_kill_nbr, NSM_Deleted},     /* LLDown            */
 551         },
 552         {
 553                 /* Loading: */
 554                 {NULL, NSM_DependUpon},             /* NoEvent           */
 555                 {nsm_packet_received, NSM_Loading}, /* PacketReceived    */
 556                 {NULL, NSM_Loading},                /* Start             */
 557                 {NULL, NSM_Loading},                /* 2-WayReceived     */
 558                 {NULL, NSM_Loading},                /* NegotiationDone   */
 559                 {NULL, NSM_Loading},                /* ExchangeDone      */
 560                 {NULL, NSM_ExStart},                /* BadLSReq          */
 561                 {NULL, NSM_Full},                   /* LoadingDone       */
 562                 {nsm_adj_ok, NSM_DependUpon},       /* AdjOK?            */
 563                 {NULL, NSM_ExStart},                /* SeqNumberMismatch */
 564                 {NULL, NSM_Init},                   /* 1-WayReceived     */
 565                 {nsm_kill_nbr, NSM_Deleted},    /* KillNbr           */
 566                 {nsm_kill_nbr, NSM_Deleted},    /* InactivityTimer   */
 567                 {nsm_kill_nbr, NSM_Deleted},    /* LLDown            */
 568         },
 569         {
 570                 /* Full: */
 571                 {NULL, NSM_DependUpon},          /* NoEvent           */
 572                 {nsm_packet_received, NSM_Full}, /* PacketReceived    */
 573                 {NULL, NSM_Full},                /* Start             */
 574                 {NULL, NSM_Full},                /* 2-WayReceived     */
 575                 {NULL, NSM_Full},                /* NegotiationDone   */
 576                 {NULL, NSM_Full},                /* ExchangeDone      */
 577                 {NULL, NSM_ExStart},             /* BadLSReq          */
 578                 {NULL, NSM_Full},                /* LoadingDone       */
 579                 {nsm_adj_ok, NSM_DependUpon},    /* AdjOK?            */
 580                 {NULL, NSM_ExStart},             /* SeqNumberMismatch */
 581                 {NULL, NSM_Init},                /* 1-WayReceived     */
 582                 {nsm_kill_nbr, NSM_Deleted},     /* KillNbr           */
 583                 {nsm_kill_nbr, NSM_Deleted},     /* InactivityTimer   */
 584                 {nsm_kill_nbr, NSM_Deleted},     /* LLDown            */
 585         },
 586 };
 587
 588 static const char *const ospf_nsm_event_str[] = {
 589         "NoEvent",         "PacketReceived",  "Start",
 590         "2-WayReceived",     "NegotiationDone", "ExchangeDone",
 591         "BadLSReq",       "LoadingDone",     "AdjOK?",
 592         "SeqNumberMismatch", "1-WayReceived",   "KillNbr",
 593         "InactivityTimer",   "LLDown",
 594 };
 595
 596 static void nsm_notice_state_change(struct ospf_neighbor *nbr, int next_state,
 597                                     int event)
 598 {
 599         /* Logging change of status. */
 600         if (IS_DEBUG_OSPF(nsm, NSM_STATUS))
 601                 zlog_debug("NSM[%s:%pI4:%s]: State change %s -> %s (%s)",
 602                            IF_NAME(nbr->oi), &nbr->router_id,
 603                            ospf_get_name(nbr->oi->ospf),
 604                            lookup_msg(ospf_nsm_state_msg, nbr->state, NULL),
 605                            lookup_msg(ospf_nsm_state_msg, next_state, NULL),
 606                            ospf_nsm_event_str[event]);
 607
 608         /* Optionally notify about adjacency changes */
 609         if (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_CHANGES)
 610             && (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL)
 611                 || (next_state == NSM_Full) || (next_state < nbr->state)))
 612                 zlog_notice("AdjChg: Nbr %pI4(%s) on %s: %s -> %s (%s)",
 613                             &nbr->router_id,
 614                             ospf_get_name(nbr->oi->ospf), IF_NAME(nbr->oi),
 615                             lookup_msg(ospf_nsm_state_msg, nbr->state, NULL),
 616                             lookup_msg(ospf_nsm_state_msg, next_state, NULL),
 617                             ospf_nsm_event_str[event]);
 618
 619         /* Advance in NSM */
 620         if (next_state > nbr->state)
 621                 monotime(&nbr->ts_last_progress);
 622         else /* regression in NSM */
 623         {
 624                 monotime(&nbr->ts_last_regress);
 625                 nbr->last_regress_str = ospf_nsm_event_str[event];
 626         }
 627 }
 628
 629 static void nsm_change_state(struct ospf_neighbor *nbr, int state)
 630 {
 631         struct ospf_interface *oi = nbr->oi;
 632         struct ospf_area *vl_area = NULL;
 633         uint8_t old_state;
 634
 635         /* Preserve old status. */
 636         old_state = nbr->state;
 637
 638         /* Change to new status. */
 639         nbr->state = state;
 640
 641         /* Statistics. */
 642         nbr->state_change++;
 643
 644         if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
 645                 vl_area = ospf_area_lookup_by_area_id(oi->ospf,
 646                                                       oi->vl_data->vl_area_id);
 647
 648         /* Generate NeighborChange ISM event.
 649          *
 650          * In response to NeighborChange, DR election is rerun. The information
 651          * from the election process is required by the router-lsa construction.
 652          *
 653          * Therefore, trigger the event prior to refreshing the LSAs. */
 654         switch (oi->state) {
 655         case ISM_DROther:
 656         case ISM_Backup:
 657         case ISM_DR:
 658                 if ((old_state < NSM_TwoWay && state >= NSM_TwoWay)
 659                     || (old_state >= NSM_TwoWay && state < NSM_TwoWay))
 660                         OSPF_ISM_EVENT_EXECUTE(oi, ISM_NeighborChange);
 661                 break;
 662         default:
 663                 /* ISM_PointToPoint -> ISM_Down, ISM_Loopback -> ISM_Down, etc.
 664                  */
 665                 break;
 666         }
 667
 668         /* One of the neighboring routers changes to/from the FULL state. */
 669         if ((old_state != NSM_Full && state == NSM_Full)
 670             || (old_state == NSM_Full && state != NSM_Full)) {
 671                 if (state == NSM_Full) {
 672                         oi->full_nbrs++;
 673                         oi->area->full_nbrs++;
 674
 675                         ospf_check_abr_status(oi->ospf);
 676
 677                         if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 678                                 if (++vl_area->full_vls == 1)
 679                                         ospf_schedule_abr_task(oi->ospf);
 680                 } else {
 681                         oi->full_nbrs--;
 682                         oi->area->full_nbrs--;
 683
 684                         ospf_check_abr_status(oi->ospf);
 685
 686                         if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 687                                 if (vl_area->full_vls > 0)
 688                                         if (--vl_area->full_vls == 0)
 689                                                 ospf_schedule_abr_task(
 690                                                         oi->ospf);
 691                 }
 692
 693                 if (CHECK_FLAG(oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL))
 694                         zlog_info(
 695                                 "%s:[%pI4:%s], %s -> %s): scheduling new router-LSA origination",
 696                                 __func__, &nbr->router_id,
 697                                 ospf_get_name(oi->ospf),
 698                                 lookup_msg(ospf_nsm_state_msg, old_state, NULL),
 699                                 lookup_msg(ospf_nsm_state_msg, state, NULL));
 700
 701                 /* Dont originate router LSA if the current
 702                  * router is acting as a HELPER for this neighbour.
 703                  */
 704                 if (!OSPF_GR_IS_ACTIVE_HELPER(nbr))
 705                         ospf_router_lsa_update_area(oi->area);
 706
 707                 if (oi->type == OSPF_IFTYPE_VIRTUALLINK) {
 708                         vl_area = ospf_area_lookup_by_area_id(
 709                                 oi->ospf, oi->vl_data->vl_area_id);
 710
 711                         if (vl_area)
 712                                 ospf_router_lsa_update_area(vl_area);
 713                 }
 714
 715                 /* Dont originate/flush network LSA if the current
 716                  * router is acting as a HELPER for this neighbour.
 717                  */
 718                 if (!OSPF_GR_IS_ACTIVE_HELPER(nbr)) {
 719                         /* Originate network-LSA. */
 720                         if (oi->state == ISM_DR) {
 721                                 if (oi->network_lsa_self
 722                                     && oi->full_nbrs == 0) {
 723                                         ospf_lsa_flush_area(
 724                                                 oi->network_lsa_self, oi->area);
 725                                         ospf_lsa_unlock(&oi->network_lsa_self);
 726                                         oi->network_lsa_self = NULL;
 727                                 } else
 728                                         ospf_network_lsa_update(oi);
 729                         }
 730                 }
 731
 732                 if (state == NSM_Full && oi->ospf->gr_info.restart_in_progress)
 733                         ospf_gr_check_adjs(oi->ospf);
 734         }
 735
 736         ospf_opaque_nsm_change(nbr, old_state);
 737
 738         /* State changes from > ExStart to <= ExStart should clear any Exchange
 739          * or Full/LSA Update related lists and state.
 740          * Potential causal events: BadLSReq, SeqNumberMismatch, AdjOK?
 741          */
 742         if ((old_state > NSM_ExStart) && (state <= NSM_ExStart))
 743                 nsm_clear_adj(nbr);
 744
 745         /* Start DD exchange protocol */
 746         if (state == NSM_ExStart) {
 747                 if (nbr->dd_seqnum == 0)
 748                         nbr->dd_seqnum = (uint32_t)frr_weak_random();
 749                 else
 750                         nbr->dd_seqnum++;
 751
 752                 nbr->dd_flags =
 753                         OSPF_DD_FLAG_I | OSPF_DD_FLAG_M | OSPF_DD_FLAG_MS;
 754                 if (CHECK_FLAG(oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL))
 755                         zlog_info(
 756                                 "%s: Initializing [DD]: %pI4 with seqnum:%x , flags:%x",
 757                                 (oi->ospf->name) ? oi->ospf->name
 758                                                  : VRF_DEFAULT_NAME,
 759                                 &nbr->router_id, nbr->dd_seqnum,
 760                                 nbr->dd_flags);
 761                 ospf_db_desc_send(nbr);
 762         }
 763
 764         /* clear cryptographic sequence number */
 765         if (state == NSM_Down)
 766                 nbr->crypt_seqnum = 0;
 767
 768         if (nbr->bfd_session)
 769                 ospf_bfd_trigger_event(nbr, old_state, state);
 770
 771         /* Preserve old status? */
 772 }
 773
 774 /* Execute NSM event process. */
 775 int ospf_nsm_event(struct thread *thread)
 776 {
 777         int event;
 778         int next_state;
 779         struct ospf_neighbor *nbr;
 780
 781         nbr = THREAD_ARG(thread);
 782         event = THREAD_VAL(thread);
 783
 784         if (IS_DEBUG_OSPF(nsm, NSM_EVENTS))
 785                 zlog_debug("NSM[%s:%pI4:%s]: %s (%s)", IF_NAME(nbr->oi),
 786                            &nbr->router_id,
 787                            ospf_get_name(nbr->oi->ospf),
 788                            lookup_msg(ospf_nsm_state_msg, nbr->state, NULL),
 789                            ospf_nsm_event_str[event]);
 790
 791         next_state = NSM[nbr->state][event].next_state;
 792
 793         /* Call function. */
 794         if (NSM[nbr->state][event].func != NULL) {
 795                 int func_state = (*(NSM[nbr->state][event].func))(nbr);
 796
 797                 if (NSM[nbr->state][event].next_state == NSM_DependUpon)
 798                         next_state = func_state;
 799                 else if (func_state) {
 800                         /* There's a mismatch between the FSM tables and what an
 801                          * FSM
 802                          * action/state-change function returned. State changes
 803                          * which
 804                          * do not have conditional/DependUpon next-states should
 805                          * not
 806                          * try set next_state.
 807                          */
 808                         flog_err(
 809                                 EC_OSPF_FSM_INVALID_STATE,
 810                                 "NSM[%s:%pI4:%s]: %s (%s): Warning: action tried to change next_state to %s",
 811                                 IF_NAME(nbr->oi), &nbr->router_id,
 812                                 ospf_get_name(nbr->oi->ospf),
 813                                 lookup_msg(ospf_nsm_state_msg, nbr->state,
 814                                            NULL),
 815                                 ospf_nsm_event_str[event],
 816                                 lookup_msg(ospf_nsm_state_msg, func_state,
 817                                            NULL));
 818                 }
 819         }
 820
 821         assert(next_state != NSM_DependUpon);
 822
 823         /* If state is changed. */
 824         if (next_state != nbr->state) {
 825                 int old_state = nbr->state;
 826
 827                 nsm_notice_state_change(nbr, next_state, event);
 828                 nsm_change_state(nbr, next_state);
 829
 830                 hook_call(ospf_nsm_change, nbr, next_state, old_state);
 831         }
 832
 833         /* Make sure timer is set. */
 834         nsm_timer_set(nbr);
 835
 836         /* When event is NSM_KillNbr, InactivityTimer or LLDown, the neighbor
 837          * is deleted.
 838          *
 839          * Rather than encode knowledge here of which events lead to NBR
 840          * delete, we take our cue from the NSM table, via the dummy
 841          * 'Deleted' neighbour state.
 842          */
 843         if (nbr->state == NSM_Deleted)
 844                 ospf_nbr_delete(nbr);
 845
 846         return 0;
 847 }
 848
 849 /* Check loading state. */
 850 void ospf_check_nbr_loading(struct ospf_neighbor *nbr)
 851 {
 852         if (nbr->state == NSM_Loading) {
 853                 if (ospf_ls_request_isempty(nbr))
 854                         OSPF_NSM_EVENT_SCHEDULE(nbr, NSM_LoadingDone);
 855                 else if (nbr->ls_req_last == NULL)
 856                         ospf_ls_req_event(nbr);
 857         }
 858 }