2 * OSPF version 2 Interface State Machine
3 * From RFC2328 [OSPF Version 2]
4 * Copyright (C) 1999, 2000 Toshiaki Takada
6 * This file is part of GNU Zebra.
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
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.
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
32 #include "ospfd/ospfd.h"
33 #include "ospfd/ospf_interface.h"
34 #include "ospfd/ospf_ism.h"
35 #include "ospfd/ospf_asbr.h"
36 #include "ospfd/ospf_lsa.h"
37 #include "ospfd/ospf_lsdb.h"
38 #include "ospfd/ospf_neighbor.h"
39 #include "ospfd/ospf_nsm.h"
40 #include "ospfd/ospf_network.h"
41 #include "ospfd/ospf_dump.h"
42 #include "ospfd/ospf_packet.h"
43 #include "ospfd/ospf_flood.h"
44 #include "ospfd/ospf_abr.h"
46 DEFINE_HOOK(ospf_ism_change
,
47 (struct ospf_interface
*oi
, int state
, int oldstate
),
48 (oi
, state
, oldstate
))
50 /* elect DR and BDR. Refer to RFC2319 section 9.4 */
51 static struct ospf_neighbor
*
52 ospf_dr_election_sub (struct list
*routers
)
54 struct listnode
*node
;
55 struct ospf_neighbor
*nbr
, *max
= NULL
;
57 /* Choose highest router priority.
58 In case of tie, choose highest Router ID. */
59 for (ALL_LIST_ELEMENTS_RO (routers
, node
, nbr
))
65 if (max
->priority
< nbr
->priority
)
67 else if (max
->priority
== nbr
->priority
)
68 if (IPV4_ADDR_CMP (&max
->router_id
, &nbr
->router_id
) < 0)
76 static struct ospf_neighbor
*
77 ospf_elect_dr (struct ospf_interface
*oi
, struct list
*el_list
)
80 struct listnode
*node
;
81 struct ospf_neighbor
*nbr
, *dr
= NULL
, *bdr
= NULL
;
83 dr_list
= list_new ();
85 /* Add neighbors to the list. */
86 for (ALL_LIST_ELEMENTS_RO (el_list
, node
, nbr
))
88 /* neighbor declared to be DR. */
90 listnode_add (dr_list
, nbr
);
92 /* Preserve neighbor BDR. */
93 if (IPV4_ADDR_SAME (&BDR (oi
), &nbr
->address
.u
.prefix4
))
97 /* Elect Designated Router. */
98 if (listcount (dr_list
) > 0)
99 dr
= ospf_dr_election_sub (dr_list
);
103 /* Set DR to interface. */
105 DR (oi
) = dr
->address
.u
.prefix4
;
109 list_delete (dr_list
);
114 static struct ospf_neighbor
*
115 ospf_elect_bdr (struct ospf_interface
*oi
, struct list
*el_list
)
117 struct list
*bdr_list
, *no_dr_list
;
118 struct listnode
*node
;
119 struct ospf_neighbor
*nbr
, *bdr
= NULL
;
121 bdr_list
= list_new ();
122 no_dr_list
= list_new ();
124 /* Add neighbors to the list. */
125 for (ALL_LIST_ELEMENTS_RO (el_list
, node
, nbr
))
127 /* neighbor declared to be DR. */
131 /* neighbor declared to be BDR. */
132 if (NBR_IS_BDR (nbr
))
133 listnode_add (bdr_list
, nbr
);
135 listnode_add (no_dr_list
, nbr
);
138 /* Elect Backup Designated Router. */
139 if (listcount (bdr_list
) > 0)
140 bdr
= ospf_dr_election_sub (bdr_list
);
142 bdr
= ospf_dr_election_sub (no_dr_list
);
144 /* Set BDR to interface. */
146 BDR (oi
) = bdr
->address
.u
.prefix4
;
150 list_delete (bdr_list
);
151 list_delete (no_dr_list
);
157 ospf_ism_state (struct ospf_interface
*oi
)
159 if (IPV4_ADDR_SAME (&DR (oi
), &oi
->address
->u
.prefix4
))
161 else if (IPV4_ADDR_SAME (&BDR (oi
), &oi
->address
->u
.prefix4
))
168 ospf_dr_eligible_routers (struct route_table
*nbrs
, struct list
*el_list
)
170 struct route_node
*rn
;
171 struct ospf_neighbor
*nbr
;
173 for (rn
= route_top (nbrs
); rn
; rn
= route_next (rn
))
174 if ((nbr
= rn
->info
) != NULL
)
175 /* Ignore 0.0.0.0 node*/
176 if (nbr
->router_id
.s_addr
!= 0)
177 /* Is neighbor eligible? */
178 if (nbr
->priority
> 0)
179 /* Is neighbor upper 2-Way? */
180 if (nbr
->state
>= NSM_TwoWay
)
181 listnode_add (el_list
, nbr
);
184 /* Generate AdjOK? NSM event. */
186 ospf_dr_change (struct ospf
*ospf
, struct route_table
*nbrs
)
188 struct route_node
*rn
;
189 struct ospf_neighbor
*nbr
;
191 for (rn
= route_top (nbrs
); rn
; rn
= route_next (rn
))
192 if ((nbr
= rn
->info
) != NULL
)
193 /* Ignore 0.0.0.0 node*/
194 if (nbr
->router_id
.s_addr
!= 0)
195 /* Is neighbor upper 2-Way? */
196 if (nbr
->state
>= NSM_TwoWay
)
198 if (!IPV4_ADDR_SAME (&nbr
->router_id
, &ospf
->router_id
))
199 OSPF_NSM_EVENT_SCHEDULE (nbr
, NSM_AdjOK
);
203 ospf_dr_election (struct ospf_interface
*oi
)
205 struct in_addr old_dr
, old_bdr
;
206 int old_state
, new_state
;
207 struct list
*el_list
;
209 /* backup current values. */
212 old_state
= oi
->state
;
214 el_list
= list_new ();
216 /* List eligible routers. */
217 ospf_dr_eligible_routers (oi
->nbrs
, el_list
);
219 /* First election of DR and BDR. */
220 ospf_elect_bdr (oi
, el_list
);
221 ospf_elect_dr (oi
, el_list
);
223 new_state
= ospf_ism_state (oi
);
225 zlog_debug ("DR-Election[1st]: Backup %s", inet_ntoa (BDR (oi
)));
226 zlog_debug ("DR-Election[1st]: DR %s", inet_ntoa (DR (oi
)));
228 if (new_state
!= old_state
&&
229 !(new_state
== ISM_DROther
&& old_state
< ISM_DROther
))
231 ospf_elect_bdr (oi
, el_list
);
232 ospf_elect_dr (oi
, el_list
);
234 new_state
= ospf_ism_state (oi
);
236 zlog_debug ("DR-Election[2nd]: Backup %s", inet_ntoa (BDR (oi
)));
237 zlog_debug ("DR-Election[2nd]: DR %s", inet_ntoa (DR (oi
)));
240 list_delete (el_list
);
242 /* if DR or BDR changes, cause AdjOK? neighbor event. */
243 if (!IPV4_ADDR_SAME (&old_dr
, &DR (oi
)) ||
244 !IPV4_ADDR_SAME (&old_bdr
, &BDR (oi
)))
245 ospf_dr_change (oi
->ospf
, oi
->nbrs
);
252 ospf_hello_timer (struct thread
*thread
)
254 struct ospf_interface
*oi
;
256 oi
= THREAD_ARG (thread
);
259 if (IS_DEBUG_OSPF (ism
, ISM_TIMERS
))
260 zlog_debug("ISM[%s]: Timer (Hello timer expire)", IF_NAME(oi
));
262 /* Sending hello packet. */
263 ospf_hello_send (oi
);
265 /* Hello timer set. */
266 OSPF_HELLO_TIMER_ON (oi
);
272 ospf_wait_timer (struct thread
*thread
)
274 struct ospf_interface
*oi
;
276 oi
= THREAD_ARG (thread
);
279 if (IS_DEBUG_OSPF (ism
, ISM_TIMERS
))
280 zlog_debug("ISM[%s]: Timer (Wait timer expire)", IF_NAME(oi
));
282 OSPF_ISM_EVENT_SCHEDULE (oi
, ISM_WaitTimer
);
287 /* Hook function called after ospf ISM event is occured. And vty's
288 network command invoke this function after making interface
291 ism_timer_set (struct ospf_interface
*oi
)
296 /* First entry point of ospf interface state machine. In this state
297 interface parameters must be set to initial values, and timers are
299 OSPF_ISM_TIMER_OFF (oi
->t_hello
);
300 OSPF_ISM_TIMER_OFF (oi
->t_wait
);
301 OSPF_ISM_TIMER_OFF (oi
->t_ls_ack
);
304 /* In this state, the interface may be looped back and will be
305 unavailable for regular data traffic. */
306 OSPF_ISM_TIMER_OFF (oi
->t_hello
);
307 OSPF_ISM_TIMER_OFF (oi
->t_wait
);
308 OSPF_ISM_TIMER_OFF (oi
->t_ls_ack
);
311 /* The router is trying to determine the identity of DRouter and
312 BDRouter. The router begin to receive and send Hello Packets. */
313 /* send first hello immediately */
314 OSPF_ISM_TIMER_MSEC_ON (oi
->t_hello
, ospf_hello_timer
, 1);
315 OSPF_ISM_TIMER_ON (oi
->t_wait
, ospf_wait_timer
,
316 OSPF_IF_PARAM (oi
, v_wait
));
317 OSPF_ISM_TIMER_OFF (oi
->t_ls_ack
);
319 case ISM_PointToPoint
:
320 /* The interface connects to a physical Point-to-point network or
321 virtual link. The router attempts to form an adjacency with
322 neighboring router. Hello packets are also sent. */
323 /* send first hello immediately */
324 OSPF_ISM_TIMER_MSEC_ON (oi
->t_hello
, ospf_hello_timer
, 1);
325 OSPF_ISM_TIMER_OFF (oi
->t_wait
);
326 OSPF_ISM_TIMER_ON (oi
->t_ls_ack
, ospf_ls_ack_timer
, oi
->v_ls_ack
);
329 /* The network type of the interface is broadcast or NBMA network,
330 and the router itself is neither Designated Router nor
331 Backup Designated Router. */
332 OSPF_HELLO_TIMER_ON (oi
);
333 OSPF_ISM_TIMER_OFF (oi
->t_wait
);
334 OSPF_ISM_TIMER_ON (oi
->t_ls_ack
, ospf_ls_ack_timer
, oi
->v_ls_ack
);
337 /* The network type of the interface is broadcast os NBMA network,
338 and the router is Backup Designated Router. */
339 OSPF_HELLO_TIMER_ON (oi
);
340 OSPF_ISM_TIMER_OFF (oi
->t_wait
);
341 OSPF_ISM_TIMER_ON (oi
->t_ls_ack
, ospf_ls_ack_timer
, oi
->v_ls_ack
);
344 /* The network type of the interface is broadcast or NBMA network,
345 and the router is Designated Router. */
346 OSPF_HELLO_TIMER_ON (oi
);
347 OSPF_ISM_TIMER_OFF (oi
->t_wait
);
348 OSPF_ISM_TIMER_ON (oi
->t_ls_ack
, ospf_ls_ack_timer
, oi
->v_ls_ack
);
354 ism_interface_up (struct ospf_interface
*oi
)
358 /* if network type is point-to-point, Point-to-MultiPoint or virtual link,
359 the state transitions to Point-to-Point. */
360 if (oi
->type
== OSPF_IFTYPE_POINTOPOINT
||
361 oi
->type
== OSPF_IFTYPE_POINTOMULTIPOINT
||
362 oi
->type
== OSPF_IFTYPE_VIRTUALLINK
)
363 next_state
= ISM_PointToPoint
;
364 /* Else if the router is not eligible to DR, the state transitions to
366 else if (PRIORITY (oi
) == 0) /* router is eligible? */
367 next_state
= ISM_DROther
;
369 /* Otherwise, the state transitions to Waiting. */
370 next_state
= ISM_Waiting
;
372 if (oi
->type
== OSPF_IFTYPE_NBMA
)
373 ospf_nbr_nbma_if_update (oi
->ospf
, oi
);
375 /* ospf_ism_event (t); */
380 ism_loop_ind (struct ospf_interface
*oi
)
384 /* call ism_interface_down. */
385 /* ret = ism_interface_down (oi); */
390 /* Interface down event handler. */
392 ism_interface_down (struct ospf_interface
*oi
)
394 ospf_if_cleanup (oi
);
400 ism_backup_seen (struct ospf_interface
*oi
)
402 return ospf_dr_election (oi
);
406 ism_wait_timer (struct ospf_interface
*oi
)
408 return ospf_dr_election (oi
);
412 ism_neighbor_change (struct ospf_interface
*oi
)
414 return ospf_dr_election (oi
);
418 ism_ignore (struct ospf_interface
*oi
)
420 if (IS_DEBUG_OSPF (ism
, ISM_EVENTS
))
421 zlog_debug("ISM[%s]: ism_ignore called", IF_NAME(oi
));
426 /* Interface State Machine */
428 int (*func
) (struct ospf_interface
*);
430 } ISM
[OSPF_ISM_STATE_MAX
][OSPF_ISM_EVENT_MAX
] =
433 /* DependUpon: dummy state. */
434 { ism_ignore
, ISM_DependUpon
}, /* NoEvent */
435 { ism_ignore
, ISM_DependUpon
}, /* InterfaceUp */
436 { ism_ignore
, ISM_DependUpon
}, /* WaitTimer */
437 { ism_ignore
, ISM_DependUpon
}, /* BackupSeen */
438 { ism_ignore
, ISM_DependUpon
}, /* NeighborChange */
439 { ism_ignore
, ISM_DependUpon
}, /* LoopInd */
440 { ism_ignore
, ISM_DependUpon
}, /* UnloopInd */
441 { ism_ignore
, ISM_DependUpon
}, /* InterfaceDown */
445 { ism_ignore
, ISM_DependUpon
}, /* NoEvent */
446 { ism_interface_up
, ISM_DependUpon
}, /* InterfaceUp */
447 { ism_ignore
, ISM_Down
}, /* WaitTimer */
448 { ism_ignore
, ISM_Down
}, /* BackupSeen */
449 { ism_ignore
, ISM_Down
}, /* NeighborChange */
450 { ism_loop_ind
, ISM_Loopback
}, /* LoopInd */
451 { ism_ignore
, ISM_Down
}, /* UnloopInd */
452 { ism_interface_down
, ISM_Down
}, /* InterfaceDown */
456 { ism_ignore
, ISM_DependUpon
}, /* NoEvent */
457 { ism_ignore
, ISM_Loopback
}, /* InterfaceUp */
458 { ism_ignore
, ISM_Loopback
}, /* WaitTimer */
459 { ism_ignore
, ISM_Loopback
}, /* BackupSeen */
460 { ism_ignore
, ISM_Loopback
}, /* NeighborChange */
461 { ism_ignore
, ISM_Loopback
}, /* LoopInd */
462 { ism_ignore
, ISM_Down
}, /* UnloopInd */
463 { ism_interface_down
, ISM_Down
}, /* InterfaceDown */
467 { ism_ignore
, ISM_DependUpon
}, /* NoEvent */
468 { ism_ignore
, ISM_Waiting
}, /* InterfaceUp */
469 { ism_wait_timer
, ISM_DependUpon
}, /* WaitTimer */
470 { ism_backup_seen
, ISM_DependUpon
}, /* BackupSeen */
471 { ism_ignore
, ISM_Waiting
}, /* NeighborChange */
472 { ism_loop_ind
, ISM_Loopback
}, /* LoopInd */
473 { ism_ignore
, ISM_Waiting
}, /* UnloopInd */
474 { ism_interface_down
, ISM_Down
}, /* InterfaceDown */
477 /* Point-to-Point: */
478 { ism_ignore
, ISM_DependUpon
}, /* NoEvent */
479 { ism_ignore
, ISM_PointToPoint
}, /* InterfaceUp */
480 { ism_ignore
, ISM_PointToPoint
}, /* WaitTimer */
481 { ism_ignore
, ISM_PointToPoint
}, /* BackupSeen */
482 { ism_ignore
, ISM_PointToPoint
}, /* NeighborChange */
483 { ism_loop_ind
, ISM_Loopback
}, /* LoopInd */
484 { ism_ignore
, ISM_PointToPoint
}, /* UnloopInd */
485 { ism_interface_down
, ISM_Down
}, /* InterfaceDown */
489 { ism_ignore
, ISM_DependUpon
}, /* NoEvent */
490 { ism_ignore
, ISM_DROther
}, /* InterfaceUp */
491 { ism_ignore
, ISM_DROther
}, /* WaitTimer */
492 { ism_ignore
, ISM_DROther
}, /* BackupSeen */
493 { ism_neighbor_change
, ISM_DependUpon
}, /* NeighborChange */
494 { ism_loop_ind
, ISM_Loopback
}, /* LoopInd */
495 { ism_ignore
, ISM_DROther
}, /* UnloopInd */
496 { ism_interface_down
, ISM_Down
}, /* InterfaceDown */
500 { ism_ignore
, ISM_DependUpon
}, /* NoEvent */
501 { ism_ignore
, ISM_Backup
}, /* InterfaceUp */
502 { ism_ignore
, ISM_Backup
}, /* WaitTimer */
503 { ism_ignore
, ISM_Backup
}, /* BackupSeen */
504 { ism_neighbor_change
, ISM_DependUpon
}, /* NeighborChange */
505 { ism_loop_ind
, ISM_Loopback
}, /* LoopInd */
506 { ism_ignore
, ISM_Backup
}, /* UnloopInd */
507 { ism_interface_down
, ISM_Down
}, /* InterfaceDown */
511 { ism_ignore
, ISM_DependUpon
}, /* NoEvent */
512 { ism_ignore
, ISM_DR
}, /* InterfaceUp */
513 { ism_ignore
, ISM_DR
}, /* WaitTimer */
514 { ism_ignore
, ISM_DR
}, /* BackupSeen */
515 { ism_neighbor_change
, ISM_DependUpon
}, /* NeighborChange */
516 { ism_loop_ind
, ISM_Loopback
}, /* LoopInd */
517 { ism_ignore
, ISM_DR
}, /* UnloopInd */
518 { ism_interface_down
, ISM_Down
}, /* InterfaceDown */
522 static const char *ospf_ism_event_str
[] =
535 ism_change_state (struct ospf_interface
*oi
, int state
)
538 struct ospf_lsa
*lsa
;
540 /* Logging change of state. */
541 if (IS_DEBUG_OSPF (ism
, ISM_STATUS
))
542 zlog_debug("ISM[%s]: State change %s -> %s", IF_NAME(oi
),
543 lookup_msg(ospf_ism_state_msg
, oi
->state
, NULL
),
544 lookup_msg(ospf_ism_state_msg
, state
, NULL
));
546 old_state
= oi
->state
;
550 hook_call(ospf_ism_change
, oi
, state
, old_state
);
552 /* Set multicast memberships appropriately for new state. */
553 ospf_if_set_multicast(oi
);
555 if (old_state
== ISM_Down
|| state
== ISM_Down
)
556 ospf_check_abr_status (oi
->ospf
);
558 /* Originate router-LSA. */
559 if (state
== ISM_Down
)
561 if (oi
->area
->act_ints
> 0)
562 oi
->area
->act_ints
--;
564 else if (old_state
== ISM_Down
)
565 oi
->area
->act_ints
++;
567 /* schedule router-LSA originate. */
568 ospf_router_lsa_update_area (oi
->area
);
570 /* Originate network-LSA. */
571 if (old_state
!= ISM_DR
&& state
== ISM_DR
)
572 ospf_network_lsa_update (oi
);
573 else if (old_state
== ISM_DR
&& state
!= ISM_DR
)
575 /* Free self originated network LSA. */
576 lsa
= oi
->network_lsa_self
;
578 ospf_lsa_flush_area (lsa
, oi
->area
);
580 ospf_lsa_unlock (&oi
->network_lsa_self
);
581 oi
->network_lsa_self
= NULL
;
584 ospf_opaque_ism_change (oi
, old_state
);
586 /* Check area border status. */
587 ospf_check_abr_status (oi
->ospf
);
590 /* Execute ISM event process. */
592 ospf_ism_event (struct thread
*thread
)
596 struct ospf_interface
*oi
;
598 oi
= THREAD_ARG (thread
);
599 event
= THREAD_VAL (thread
);
602 next_state
= (*(ISM
[oi
->state
][event
].func
))(oi
);
605 next_state
= ISM
[oi
->state
][event
].next_state
;
607 if (IS_DEBUG_OSPF (ism
, ISM_EVENTS
))
608 zlog_debug("ISM[%s]: %s (%s)", IF_NAME(oi
),
609 lookup_msg(ospf_ism_state_msg
, oi
->state
, NULL
),
610 ospf_ism_event_str
[event
]);
612 /* If state is changed. */
613 if (next_state
!= oi
->state
)
614 ism_change_state (oi
, next_state
);
616 /* Make sure timer is set. */