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
->xref
->xref
.file
,
78 thread
->xref
->xref
.line
);
82 if (circuit
->u
.bc
.run_dr_elect
[level
- 1])
83 zlog_warn("isis_run_dr(): run_dr_elect already set for l%d", level
);
85 circuit
->u
.bc
.t_run_dr
[level
- 1] = NULL
;
86 circuit
->u
.bc
.run_dr_elect
[level
- 1] = 1;
91 static int isis_check_dr_change(struct isis_adjacency
*adj
, int level
)
95 if (adj
->dis_record
[level
- 1].dis
96 != adj
->dis_record
[(1 * ISIS_LEVELS
) + level
- 1].dis
)
97 /* was there a DIS state transition ? */
99 adj
->dischanges
[level
- 1]++;
100 /* ok rotate the history list through */
101 for (i
= DIS_RECORDS
- 1; i
> 0; i
--) {
102 adj
->dis_record
[(i
* ISIS_LEVELS
) + level
- 1].dis
=
103 adj
->dis_record
[((i
- 1) * ISIS_LEVELS
) + level
106 adj
->dis_record
[(i
* ISIS_LEVELS
) + level
- 1]
108 adj
->dis_record
[((i
- 1) * ISIS_LEVELS
) + level
116 int isis_dr_elect(struct isis_circuit
*circuit
, int level
)
119 struct listnode
*node
;
120 struct isis_adjacency
*adj
, *adj_dr
= NULL
;
121 struct list
*list
= list_new();
123 int biggest_prio
= -1;
124 int cmp_res
, retval
= ISIS_OK
;
126 own_prio
= circuit
->priority
[level
- 1];
127 adjdb
= circuit
->u
.bc
.adjdb
[level
- 1];
130 zlog_warn("isis_dr_elect() adjdb == NULL");
134 isis_adj_build_up_list(adjdb
, list
);
137 * Loop the adjacencies and find the one with the biggest priority
139 for (ALL_LIST_ELEMENTS_RO(list
, node
, adj
)) {
140 /* clear flag for show output */
141 adj
->dis_record
[level
- 1].dis
= ISIS_IS_NOT_DIS
;
142 adj
->dis_record
[level
- 1].last_dis_change
= time(NULL
);
144 if (adj
->prio
[level
- 1] > biggest_prio
) {
145 biggest_prio
= adj
->prio
[level
- 1];
147 } else if (adj
->prio
[level
- 1] == biggest_prio
) {
149 * Comparison of MACs breaks a tie
152 cmp_res
= memcmp(adj_dr
->snpa
, adj
->snpa
,
159 "isis_dr_elect(): multiple adjacencies with same SNPA");
168 * Could not find the DR - means we are alone. Resign if we were
171 if (circuit
->u
.bc
.is_dr
[level
- 1])
172 retval
= isis_dr_resign(circuit
, level
);
178 * Now we have the DR adjacency, compare it to self
180 if (adj_dr
->prio
[level
- 1] < own_prio
181 || (adj_dr
->prio
[level
- 1] == own_prio
182 && memcmp(adj_dr
->snpa
, circuit
->u
.bc
.snpa
, ETH_ALEN
) < 0)) {
183 adj_dr
->dis_record
[level
- 1].dis
= ISIS_IS_NOT_DIS
;
184 adj_dr
->dis_record
[level
- 1].last_dis_change
= time(NULL
);
186 /* rotate the history log */
187 for (ALL_LIST_ELEMENTS_RO(list
, node
, adj
))
188 isis_check_dr_change(adj
, level
);
190 /* We are the DR, commence DR */
191 if (circuit
->u
.bc
.is_dr
[level
- 1] == 0 && listcount(list
) > 0)
192 retval
= isis_dr_commence(circuit
, level
);
194 /* ok we have found the DIS - lets mark the adjacency */
195 /* set flag for show output */
196 adj_dr
->dis_record
[level
- 1].dis
= ISIS_IS_DIS
;
197 adj_dr
->dis_record
[level
- 1].last_dis_change
= time(NULL
);
199 /* now loop through a second time to check if there has been a
201 * if yes rotate the history log
204 for (ALL_LIST_ELEMENTS_RO(list
, node
, adj
))
205 isis_check_dr_change(adj
, level
);
208 * We are not DR - if we were -> resign
210 if (circuit
->u
.bc
.is_dr
[level
- 1])
211 retval
= isis_dr_resign(circuit
, level
);
217 int isis_dr_resign(struct isis_circuit
*circuit
, int level
)
219 uint8_t id
[ISIS_SYS_ID_LEN
+ 2];
221 zlog_debug("isis_dr_resign l%d", level
);
223 circuit
->u
.bc
.is_dr
[level
- 1] = 0;
224 circuit
->u
.bc
.run_dr_elect
[level
- 1] = 0;
225 thread_cancel(&circuit
->u
.bc
.t_run_dr
[level
- 1]);
226 thread_cancel(&circuit
->u
.bc
.t_refresh_pseudo_lsp
[level
- 1]);
227 circuit
->lsp_regenerate_pending
[level
- 1] = 0;
229 memcpy(id
, circuit
->isis
->sysid
, ISIS_SYS_ID_LEN
);
230 LSP_PSEUDO_ID(id
) = circuit
->circuit_id
;
231 LSP_FRAGMENT(id
) = 0;
232 lsp_purge_pseudo(id
, circuit
, level
);
235 memset(circuit
->u
.bc
.l1_desig_is
, 0, ISIS_SYS_ID_LEN
+ 1);
237 thread_add_timer(master
, send_l1_psnp
, circuit
,
238 isis_jitter(circuit
->psnp_interval
[level
- 1],
240 &circuit
->t_send_psnp
[0]);
242 memset(circuit
->u
.bc
.l2_desig_is
, 0, ISIS_SYS_ID_LEN
+ 1);
244 thread_add_timer(master
, send_l2_psnp
, circuit
,
245 isis_jitter(circuit
->psnp_interval
[level
- 1],
247 &circuit
->t_send_psnp
[1]);
250 thread_cancel(&circuit
->t_send_csnp
[level
- 1]);
252 thread_add_timer(master
, isis_run_dr
,
253 &circuit
->level_arg
[level
- 1],
254 2 * circuit
->hello_interval
[level
- 1],
255 &circuit
->u
.bc
.t_run_dr
[level
- 1]);
258 thread_add_event(master
, isis_event_dis_status_change
, circuit
, 0,
264 int isis_dr_commence(struct isis_circuit
*circuit
, int level
)
266 uint8_t old_dr
[ISIS_SYS_ID_LEN
+ 2];
269 zlog_debug("isis_dr_commence l%d", level
);
271 /* Lets keep a pause in DR election */
272 circuit
->u
.bc
.run_dr_elect
[level
- 1] = 0;
273 circuit
->u
.bc
.is_dr
[level
- 1] = 1;
276 memcpy(old_dr
, circuit
->u
.bc
.l1_desig_is
, ISIS_SYS_ID_LEN
+ 1);
277 LSP_FRAGMENT(old_dr
) = 0;
278 if (LSP_PSEUDO_ID(old_dr
)) {
279 /* there was a dr elected, purge its LSPs from the db */
280 lsp_purge_pseudo(old_dr
, circuit
, level
);
282 memcpy(circuit
->u
.bc
.l1_desig_is
, circuit
->isis
->sysid
,
284 *(circuit
->u
.bc
.l1_desig_is
+ ISIS_SYS_ID_LEN
) =
287 assert(circuit
->circuit_id
); /* must be non-zero */
288 /* if (circuit->t_send_l1_psnp)
289 thread_cancel (circuit->t_send_l1_psnp); */
290 lsp_generate_pseudo(circuit
, 1);
292 thread_add_timer(master
, send_l1_csnp
, circuit
,
293 isis_jitter(circuit
->csnp_interval
[level
- 1],
295 &circuit
->t_send_csnp
[0]);
298 memcpy(old_dr
, circuit
->u
.bc
.l2_desig_is
, ISIS_SYS_ID_LEN
+ 1);
299 LSP_FRAGMENT(old_dr
) = 0;
300 if (LSP_PSEUDO_ID(old_dr
)) {
301 /* there was a dr elected, purge its LSPs from the db */
302 lsp_purge_pseudo(old_dr
, circuit
, level
);
304 memcpy(circuit
->u
.bc
.l2_desig_is
, circuit
->isis
->sysid
,
306 *(circuit
->u
.bc
.l2_desig_is
+ ISIS_SYS_ID_LEN
) =
309 assert(circuit
->circuit_id
); /* must be non-zero */
310 /* if (circuit->t_send_l1_psnp)
311 thread_cancel (circuit->t_send_l1_psnp); */
312 lsp_generate_pseudo(circuit
, 2);
314 thread_add_timer(master
, send_l2_csnp
, circuit
,
315 isis_jitter(circuit
->csnp_interval
[level
- 1],
317 &circuit
->t_send_csnp
[1]);
320 thread_add_timer(master
, isis_run_dr
,
321 &circuit
->level_arg
[level
- 1],
322 2 * circuit
->hello_interval
[level
- 1],
323 &circuit
->u
.bc
.t_run_dr
[level
- 1]);
324 thread_add_event(master
, isis_event_dis_status_change
, circuit
, 0,