2 * IS-IS Rout(e)ing protocol - isis_dr.c
3 * IS-IS designated router related routines
5 * Copyright (C) 2001,2002 Sampo Saaristo
6 * Tampere University of Technology
7 * Institute of Communications Engineering
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public Licenseas published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
14 * This program is distributed in the hope that it will be useful,but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19 * You should have received a copy of the GNU General Public License along
20 * with this program; see the file COPYING; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
35 #include "isisd/isis_constants.h"
36 #include "isisd/isis_common.h"
37 #include "isisd/isis_misc.h"
38 #include "isisd/isis_flags.h"
39 #include "isisd/isis_circuit.h"
40 #include "isisd/isisd.h"
41 #include "isisd/isis_adjacency.h"
42 #include "isisd/isis_constants.h"
43 #include "isisd/isis_pdu.h"
44 #include "isisd/isis_lsp.h"
45 #include "isisd/isis_dr.h"
46 #include "isisd/isis_events.h"
48 const char *isis_disflag2string(int disflag
)
59 return "unknown DIS state";
61 return NULL
; /* not reached */
64 int isis_run_dr(struct thread
*thread
)
66 struct isis_circuit_arg
*arg
= THREAD_ARG(thread
);
70 struct isis_circuit
*circuit
= arg
->circuit
;
71 int level
= arg
->level
;
75 if (circuit
->circ_type
!= CIRCUIT_T_BROADCAST
) {
76 zlog_warn("%s: scheduled for non broadcast circuit from %s:%d",
77 __func__
, thread
->schedfrom
, thread
->schedfrom_line
);
81 if (circuit
->u
.bc
.run_dr_elect
[level
- 1])
82 zlog_warn("isis_run_dr(): run_dr_elect already set for l%d", level
);
84 circuit
->u
.bc
.t_run_dr
[level
- 1] = NULL
;
85 circuit
->u
.bc
.run_dr_elect
[level
- 1] = 1;
90 static int isis_check_dr_change(struct isis_adjacency
*adj
, int level
)
94 if (adj
->dis_record
[level
- 1].dis
95 != adj
->dis_record
[(1 * ISIS_LEVELS
) + level
- 1].dis
)
96 /* was there a DIS state transition ? */
98 adj
->dischanges
[level
- 1]++;
99 /* ok rotate the history list through */
100 for (i
= DIS_RECORDS
- 1; i
> 0; i
--) {
101 adj
->dis_record
[(i
* ISIS_LEVELS
) + level
- 1].dis
=
102 adj
->dis_record
[((i
- 1) * ISIS_LEVELS
) + level
105 adj
->dis_record
[(i
* ISIS_LEVELS
) + level
- 1]
107 adj
->dis_record
[((i
- 1) * ISIS_LEVELS
) + level
115 int isis_dr_elect(struct isis_circuit
*circuit
, int level
)
118 struct listnode
*node
;
119 struct isis_adjacency
*adj
, *adj_dr
= NULL
;
120 struct list
*list
= list_new();
122 int biggest_prio
= -1;
123 int cmp_res
, retval
= ISIS_OK
;
125 own_prio
= circuit
->priority
[level
- 1];
126 adjdb
= circuit
->u
.bc
.adjdb
[level
- 1];
129 zlog_warn("isis_dr_elect() adjdb == NULL");
133 isis_adj_build_up_list(adjdb
, list
);
136 * Loop the adjacencies and find the one with the biggest priority
138 for (ALL_LIST_ELEMENTS_RO(list
, node
, adj
)) {
139 /* clear flag for show output */
140 adj
->dis_record
[level
- 1].dis
= ISIS_IS_NOT_DIS
;
141 adj
->dis_record
[level
- 1].last_dis_change
= time(NULL
);
143 if (adj
->prio
[level
- 1] > biggest_prio
) {
144 biggest_prio
= adj
->prio
[level
- 1];
146 } else if (adj
->prio
[level
- 1] == biggest_prio
) {
148 * Comparison of MACs breaks a tie
151 cmp_res
= memcmp(adj_dr
->snpa
, adj
->snpa
,
158 "isis_dr_elect(): multiple adjacencies with same SNPA");
167 * Could not find the DR - means we are alone. Resign if we were
170 if (circuit
->u
.bc
.is_dr
[level
- 1])
171 retval
= isis_dr_resign(circuit
, level
);
177 * Now we have the DR adjacency, compare it to self
179 if (adj_dr
->prio
[level
- 1] < own_prio
180 || (adj_dr
->prio
[level
- 1] == own_prio
181 && memcmp(adj_dr
->snpa
, circuit
->u
.bc
.snpa
, ETH_ALEN
) < 0)) {
182 adj_dr
->dis_record
[level
- 1].dis
= ISIS_IS_NOT_DIS
;
183 adj_dr
->dis_record
[level
- 1].last_dis_change
= time(NULL
);
185 /* rotate the history log */
186 for (ALL_LIST_ELEMENTS_RO(list
, node
, adj
))
187 isis_check_dr_change(adj
, level
);
189 /* We are the DR, commence DR */
190 if (circuit
->u
.bc
.is_dr
[level
- 1] == 0 && listcount(list
) > 0)
191 retval
= isis_dr_commence(circuit
, level
);
193 /* ok we have found the DIS - lets mark the adjacency */
194 /* set flag for show output */
195 adj_dr
->dis_record
[level
- 1].dis
= ISIS_IS_DIS
;
196 adj_dr
->dis_record
[level
- 1].last_dis_change
= time(NULL
);
198 /* now loop through a second time to check if there has been a
200 * if yes rotate the history log
203 for (ALL_LIST_ELEMENTS_RO(list
, node
, adj
))
204 isis_check_dr_change(adj
, level
);
207 * We are not DR - if we were -> resign
209 if (circuit
->u
.bc
.is_dr
[level
- 1])
210 retval
= isis_dr_resign(circuit
, level
);
216 int isis_dr_resign(struct isis_circuit
*circuit
, int level
)
218 uint8_t id
[ISIS_SYS_ID_LEN
+ 2];
220 zlog_debug("isis_dr_resign l%d", level
);
222 circuit
->u
.bc
.is_dr
[level
- 1] = 0;
223 circuit
->u
.bc
.run_dr_elect
[level
- 1] = 0;
224 THREAD_TIMER_OFF(circuit
->u
.bc
.t_run_dr
[level
- 1]);
225 THREAD_TIMER_OFF(circuit
->u
.bc
.t_refresh_pseudo_lsp
[level
- 1]);
226 circuit
->lsp_regenerate_pending
[level
- 1] = 0;
228 memcpy(id
, isis
->sysid
, ISIS_SYS_ID_LEN
);
229 LSP_PSEUDO_ID(id
) = circuit
->circuit_id
;
230 LSP_FRAGMENT(id
) = 0;
231 lsp_purge_pseudo(id
, circuit
, level
);
234 memset(circuit
->u
.bc
.l1_desig_is
, 0, ISIS_SYS_ID_LEN
+ 1);
236 thread_add_timer(master
, send_l1_psnp
, circuit
,
237 isis_jitter(circuit
->psnp_interval
[level
- 1],
239 &circuit
->t_send_psnp
[0]);
241 memset(circuit
->u
.bc
.l2_desig_is
, 0, ISIS_SYS_ID_LEN
+ 1);
243 thread_add_timer(master
, send_l2_psnp
, circuit
,
244 isis_jitter(circuit
->psnp_interval
[level
- 1],
246 &circuit
->t_send_psnp
[1]);
249 THREAD_TIMER_OFF(circuit
->t_send_csnp
[level
- 1]);
251 thread_add_timer(master
, isis_run_dr
,
252 &circuit
->level_arg
[level
- 1],
253 2 * circuit
->hello_interval
[level
- 1],
254 &circuit
->u
.bc
.t_run_dr
[level
- 1]);
257 thread_add_event(master
, isis_event_dis_status_change
, circuit
, 0,
263 int isis_dr_commence(struct isis_circuit
*circuit
, int level
)
265 uint8_t old_dr
[ISIS_SYS_ID_LEN
+ 2];
267 if (isis
->debugs
& DEBUG_EVENTS
)
268 zlog_debug("isis_dr_commence l%d", level
);
270 /* Lets keep a pause in DR election */
271 circuit
->u
.bc
.run_dr_elect
[level
- 1] = 0;
272 circuit
->u
.bc
.is_dr
[level
- 1] = 1;
275 memcpy(old_dr
, circuit
->u
.bc
.l1_desig_is
, ISIS_SYS_ID_LEN
+ 1);
276 LSP_FRAGMENT(old_dr
) = 0;
277 if (LSP_PSEUDO_ID(old_dr
)) {
278 /* there was a dr elected, purge its LSPs from the db */
279 lsp_purge_pseudo(old_dr
, circuit
, level
);
281 memcpy(circuit
->u
.bc
.l1_desig_is
, isis
->sysid
, ISIS_SYS_ID_LEN
);
282 *(circuit
->u
.bc
.l1_desig_is
+ ISIS_SYS_ID_LEN
) =
285 assert(circuit
->circuit_id
); /* must be non-zero */
286 /* if (circuit->t_send_l1_psnp)
287 thread_cancel (circuit->t_send_l1_psnp); */
288 lsp_generate_pseudo(circuit
, 1);
290 thread_add_timer(master
, send_l1_csnp
, circuit
,
291 isis_jitter(circuit
->csnp_interval
[level
- 1],
293 &circuit
->t_send_csnp
[0]);
296 memcpy(old_dr
, circuit
->u
.bc
.l2_desig_is
, ISIS_SYS_ID_LEN
+ 1);
297 LSP_FRAGMENT(old_dr
) = 0;
298 if (LSP_PSEUDO_ID(old_dr
)) {
299 /* there was a dr elected, purge its LSPs from the db */
300 lsp_purge_pseudo(old_dr
, circuit
, level
);
302 memcpy(circuit
->u
.bc
.l2_desig_is
, isis
->sysid
, ISIS_SYS_ID_LEN
);
303 *(circuit
->u
.bc
.l2_desig_is
+ ISIS_SYS_ID_LEN
) =
306 assert(circuit
->circuit_id
); /* must be non-zero */
307 /* if (circuit->t_send_l1_psnp)
308 thread_cancel (circuit->t_send_l1_psnp); */
309 lsp_generate_pseudo(circuit
, 2);
311 thread_add_timer(master
, send_l2_csnp
, circuit
,
312 isis_jitter(circuit
->csnp_interval
[level
- 1],
314 &circuit
->t_send_csnp
[1]);
317 thread_add_timer(master
, isis_run_dr
,
318 &circuit
->level_arg
[level
- 1],
319 2 * circuit
->hello_interval
[level
- 1],
320 &circuit
->u
.bc
.t_run_dr
[level
- 1]);
321 thread_add_event(master
, isis_event_dis_status_change
, circuit
, 0,