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1/*
2 * Spanning tree protocol; generic parts
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 */
13#include <linux/kernel.h>
14#include <linux/rculist.h>
15
16#include "br_private.h"
17#include "br_private_stp.h"
18
19/* since time values in bpdu are in jiffies and then scaled (1/256)
20 * before sending, make sure that is at least one.
21 */
22#define MESSAGE_AGE_INCR ((HZ < 256) ? 1 : (HZ/256))
23
24static const char *const br_port_state_names[] = {
25 [BR_STATE_DISABLED] = "disabled",
26 [BR_STATE_LISTENING] = "listening",
27 [BR_STATE_LEARNING] = "learning",
28 [BR_STATE_FORWARDING] = "forwarding",
29 [BR_STATE_BLOCKING] = "blocking",
30};
31
32void br_log_state(const struct net_bridge_port *p)
33{
34 br_info(p->br, "port %u(%s) entering %s state\n",
35 (unsigned) p->port_no, p->dev->name,
36 br_port_state_names[p->state]);
37}
38
39/* called under bridge lock */
40struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
41{
42 struct net_bridge_port *p;
43
44 list_for_each_entry_rcu(p, &br->port_list, list) {
45 if (p->port_no == port_no)
46 return p;
47 }
48
49 return NULL;
50}
51
52/* called under bridge lock */
53static int br_should_become_root_port(const struct net_bridge_port *p,
54 u16 root_port)
55{
56 struct net_bridge *br;
57 struct net_bridge_port *rp;
58 int t;
59
60 br = p->br;
61 if (p->state == BR_STATE_DISABLED ||
62 br_is_designated_port(p))
63 return 0;
64
65 if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
66 return 0;
67
68 if (!root_port)
69 return 1;
70
71 rp = br_get_port(br, root_port);
72
73 t = memcmp(&p->designated_root, &rp->designated_root, 8);
74 if (t < 0)
75 return 1;
76 else if (t > 0)
77 return 0;
78
79 if (p->designated_cost + p->path_cost <
80 rp->designated_cost + rp->path_cost)
81 return 1;
82 else if (p->designated_cost + p->path_cost >
83 rp->designated_cost + rp->path_cost)
84 return 0;
85
86 t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
87 if (t < 0)
88 return 1;
89 else if (t > 0)
90 return 0;
91
92 if (p->designated_port < rp->designated_port)
93 return 1;
94 else if (p->designated_port > rp->designated_port)
95 return 0;
96
97 if (p->port_id < rp->port_id)
98 return 1;
99
100 return 0;
101}
102
103/* called under bridge lock */
104static void br_root_selection(struct net_bridge *br)
105{
106 struct net_bridge_port *p;
107 u16 root_port = 0;
108
109 list_for_each_entry(p, &br->port_list, list) {
110 if (br_should_become_root_port(p, root_port))
111 root_port = p->port_no;
112 }
113
114 br->root_port = root_port;
115
116 if (!root_port) {
117 br->designated_root = br->bridge_id;
118 br->root_path_cost = 0;
119 } else {
120 p = br_get_port(br, root_port);
121 br->designated_root = p->designated_root;
122 br->root_path_cost = p->designated_cost + p->path_cost;
123 }
124}
125
126/* called under bridge lock */
127void br_become_root_bridge(struct net_bridge *br)
128{
129 br->max_age = br->bridge_max_age;
130 br->hello_time = br->bridge_hello_time;
131 br->forward_delay = br->bridge_forward_delay;
132 br_topology_change_detection(br);
133 del_timer(&br->tcn_timer);
134
135 if (br->dev->flags & IFF_UP) {
136 br_config_bpdu_generation(br);
137 mod_timer(&br->hello_timer, jiffies + br->hello_time);
138 }
139}
140
141/* called under bridge lock */
142void br_transmit_config(struct net_bridge_port *p)
143{
144 struct br_config_bpdu bpdu;
145 struct net_bridge *br;
146
147 if (timer_pending(&p->hold_timer)) {
148 p->config_pending = 1;
149 return;
150 }
151
152 br = p->br;
153
154 bpdu.topology_change = br->topology_change;
155 bpdu.topology_change_ack = p->topology_change_ack;
156 bpdu.root = br->designated_root;
157 bpdu.root_path_cost = br->root_path_cost;
158 bpdu.bridge_id = br->bridge_id;
159 bpdu.port_id = p->port_id;
160 if (br_is_root_bridge(br))
161 bpdu.message_age = 0;
162 else {
163 struct net_bridge_port *root
164 = br_get_port(br, br->root_port);
165 bpdu.message_age = (jiffies - root->designated_age)
166 + MESSAGE_AGE_INCR;
167 }
168 bpdu.max_age = br->max_age;
169 bpdu.hello_time = br->hello_time;
170 bpdu.forward_delay = br->forward_delay;
171
172 if (bpdu.message_age < br->max_age) {
173 br_send_config_bpdu(p, &bpdu);
174 p->topology_change_ack = 0;
175 p->config_pending = 0;
176 mod_timer(&p->hold_timer,
177 round_jiffies(jiffies + BR_HOLD_TIME));
178 }
179}
180
181/* called under bridge lock */
182static void br_record_config_information(struct net_bridge_port *p,
183 const struct br_config_bpdu *bpdu)
184{
185 p->designated_root = bpdu->root;
186 p->designated_cost = bpdu->root_path_cost;
187 p->designated_bridge = bpdu->bridge_id;
188 p->designated_port = bpdu->port_id;
189 p->designated_age = jiffies + bpdu->message_age;
190
191 mod_timer(&p->message_age_timer, jiffies
192 + (p->br->max_age - bpdu->message_age));
193}
194
195/* called under bridge lock */
196static void br_record_config_timeout_values(struct net_bridge *br,
197 const struct br_config_bpdu *bpdu)
198{
199 br->max_age = bpdu->max_age;
200 br->hello_time = bpdu->hello_time;
201 br->forward_delay = bpdu->forward_delay;
202 br->topology_change = bpdu->topology_change;
203}
204
205/* called under bridge lock */
206void br_transmit_tcn(struct net_bridge *br)
207{
208 br_send_tcn_bpdu(br_get_port(br, br->root_port));
209}
210
211/* called under bridge lock */
212static int br_should_become_designated_port(const struct net_bridge_port *p)
213{
214 struct net_bridge *br;
215 int t;
216
217 br = p->br;
218 if (br_is_designated_port(p))
219 return 1;
220
221 if (memcmp(&p->designated_root, &br->designated_root, 8))
222 return 1;
223
224 if (br->root_path_cost < p->designated_cost)
225 return 1;
226 else if (br->root_path_cost > p->designated_cost)
227 return 0;
228
229 t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
230 if (t < 0)
231 return 1;
232 else if (t > 0)
233 return 0;
234
235 if (p->port_id < p->designated_port)
236 return 1;
237
238 return 0;
239}
240
241/* called under bridge lock */
242static void br_designated_port_selection(struct net_bridge *br)
243{
244 struct net_bridge_port *p;
245
246 list_for_each_entry(p, &br->port_list, list) {
247 if (p->state != BR_STATE_DISABLED &&
248 br_should_become_designated_port(p))
249 br_become_designated_port(p);
250
251 }
252}
253
254/* called under bridge lock */
255static int br_supersedes_port_info(const struct net_bridge_port *p,
256 const struct br_config_bpdu *bpdu)
257{
258 int t;
259
260 t = memcmp(&bpdu->root, &p->designated_root, 8);
261 if (t < 0)
262 return 1;
263 else if (t > 0)
264 return 0;
265
266 if (bpdu->root_path_cost < p->designated_cost)
267 return 1;
268 else if (bpdu->root_path_cost > p->designated_cost)
269 return 0;
270
271 t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
272 if (t < 0)
273 return 1;
274 else if (t > 0)
275 return 0;
276
277 if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
278 return 1;
279
280 if (bpdu->port_id <= p->designated_port)
281 return 1;
282
283 return 0;
284}
285
286/* called under bridge lock */
287static void br_topology_change_acknowledged(struct net_bridge *br)
288{
289 br->topology_change_detected = 0;
290 del_timer(&br->tcn_timer);
291}
292
293/* called under bridge lock */
294void br_topology_change_detection(struct net_bridge *br)
295{
296 int isroot = br_is_root_bridge(br);
297
298 if (br->stp_enabled != BR_KERNEL_STP)
299 return;
300
301 br_info(br, "topology change detected, %s\n",
302 isroot ? "propagating" : "sending tcn bpdu");
303
304 if (isroot) {
305 br->topology_change = 1;
306 mod_timer(&br->topology_change_timer, jiffies
307 + br->bridge_forward_delay + br->bridge_max_age);
308 } else if (!br->topology_change_detected) {
309 br_transmit_tcn(br);
310 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
311 }
312
313 br->topology_change_detected = 1;
314}
315
316/* called under bridge lock */
317void br_config_bpdu_generation(struct net_bridge *br)
318{
319 struct net_bridge_port *p;
320
321 list_for_each_entry(p, &br->port_list, list) {
322 if (p->state != BR_STATE_DISABLED &&
323 br_is_designated_port(p))
324 br_transmit_config(p);
325 }
326}
327
328/* called under bridge lock */
329static void br_reply(struct net_bridge_port *p)
330{
331 br_transmit_config(p);
332}
333
334/* called under bridge lock */
335void br_configuration_update(struct net_bridge *br)
336{
337 br_root_selection(br);
338 br_designated_port_selection(br);
339}
340
341/* called under bridge lock */
342void br_become_designated_port(struct net_bridge_port *p)
343{
344 struct net_bridge *br;
345
346 br = p->br;
347 p->designated_root = br->designated_root;
348 p->designated_cost = br->root_path_cost;
349 p->designated_bridge = br->bridge_id;
350 p->designated_port = p->port_id;
351}
352
353
354/* called under bridge lock */
355static void br_make_blocking(struct net_bridge_port *p)
356{
357 if (p->state != BR_STATE_DISABLED &&
358 p->state != BR_STATE_BLOCKING) {
359 if (p->state == BR_STATE_FORWARDING ||
360 p->state == BR_STATE_LEARNING)
361 br_topology_change_detection(p->br);
362
363 p->state = BR_STATE_BLOCKING;
364 br_log_state(p);
365 br_ifinfo_notify(RTM_NEWLINK, p);
366
367 del_timer(&p->forward_delay_timer);
368 }
369}
370
371/* called under bridge lock */
372static void br_make_forwarding(struct net_bridge_port *p)
373{
374 struct net_bridge *br = p->br;
375
376 if (p->state != BR_STATE_BLOCKING)
377 return;
378
379 if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
380 p->state = BR_STATE_FORWARDING;
381 br_topology_change_detection(br);
382 del_timer(&p->forward_delay_timer);
383 } else if (br->stp_enabled == BR_KERNEL_STP)
384 p->state = BR_STATE_LISTENING;
385 else
386 p->state = BR_STATE_LEARNING;
387
388 br_multicast_enable_port(p);
389 br_log_state(p);
390 br_ifinfo_notify(RTM_NEWLINK, p);
391
392 if (br->forward_delay != 0)
393 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
394}
395
396/* called under bridge lock */
397void br_port_state_selection(struct net_bridge *br)
398{
399 struct net_bridge_port *p;
400 unsigned int liveports = 0;
401
402 /* Don't change port states if userspace is handling STP */
403 if (br->stp_enabled == BR_USER_STP)
404 return;
405
406 list_for_each_entry(p, &br->port_list, list) {
407 if (p->state == BR_STATE_DISABLED)
408 continue;
409
410 if (p->port_no == br->root_port) {
411 p->config_pending = 0;
412 p->topology_change_ack = 0;
413 br_make_forwarding(p);
414 } else if (br_is_designated_port(p)) {
415 del_timer(&p->message_age_timer);
416 br_make_forwarding(p);
417 } else {
418 p->config_pending = 0;
419 p->topology_change_ack = 0;
420 br_make_blocking(p);
421 }
422
423 if (p->state == BR_STATE_FORWARDING)
424 ++liveports;
425 }
426
427 if (liveports == 0)
428 netif_carrier_off(br->dev);
429 else
430 netif_carrier_on(br->dev);
431}
432
433/* called under bridge lock */
434static void br_topology_change_acknowledge(struct net_bridge_port *p)
435{
436 p->topology_change_ack = 1;
437 br_transmit_config(p);
438}
439
440/* called under bridge lock */
441void br_received_config_bpdu(struct net_bridge_port *p,
442 const struct br_config_bpdu *bpdu)
443{
444 struct net_bridge *br;
445 int was_root;
446
447 br = p->br;
448 was_root = br_is_root_bridge(br);
449
450 if (br_supersedes_port_info(p, bpdu)) {
451 br_record_config_information(p, bpdu);
452 br_configuration_update(br);
453 br_port_state_selection(br);
454
455 if (!br_is_root_bridge(br) && was_root) {
456 del_timer(&br->hello_timer);
457 if (br->topology_change_detected) {
458 del_timer(&br->topology_change_timer);
459 br_transmit_tcn(br);
460
461 mod_timer(&br->tcn_timer,
462 jiffies + br->bridge_hello_time);
463 }
464 }
465
466 if (p->port_no == br->root_port) {
467 br_record_config_timeout_values(br, bpdu);
468 br_config_bpdu_generation(br);
469 if (bpdu->topology_change_ack)
470 br_topology_change_acknowledged(br);
471 }
472 } else if (br_is_designated_port(p)) {
473 br_reply(p);
474 }
475}
476
477/* called under bridge lock */
478void br_received_tcn_bpdu(struct net_bridge_port *p)
479{
480 if (br_is_designated_port(p)) {
481 br_info(p->br, "port %u(%s) received tcn bpdu\n",
482 (unsigned) p->port_no, p->dev->name);
483
484 br_topology_change_detection(p->br);
485 br_topology_change_acknowledge(p);
486 }
487}
488
489/* Change bridge STP parameter */
490int br_set_hello_time(struct net_bridge *br, unsigned long val)
491{
492 unsigned long t = clock_t_to_jiffies(val);
493
494 if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
495 return -ERANGE;
496
497 spin_lock_bh(&br->lock);
498 br->bridge_hello_time = t;
499 if (br_is_root_bridge(br))
500 br->hello_time = br->bridge_hello_time;
501 spin_unlock_bh(&br->lock);
502 return 0;
503}
504
505int br_set_max_age(struct net_bridge *br, unsigned long val)
506{
507 unsigned long t = clock_t_to_jiffies(val);
508
509 if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
510 return -ERANGE;
511
512 spin_lock_bh(&br->lock);
513 br->bridge_max_age = t;
514 if (br_is_root_bridge(br))
515 br->max_age = br->bridge_max_age;
516 spin_unlock_bh(&br->lock);
517 return 0;
518
519}
520
521int br_set_forward_delay(struct net_bridge *br, unsigned long val)
522{
523 unsigned long t = clock_t_to_jiffies(val);
524
525 if (br->stp_enabled != BR_NO_STP &&
526 (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
527 return -ERANGE;
528
529 spin_lock_bh(&br->lock);
530 br->bridge_forward_delay = t;
531 if (br_is_root_bridge(br))
532 br->forward_delay = br->bridge_forward_delay;
533 spin_unlock_bh(&br->lock);
534 return 0;
535}
1/*
2 * Spanning tree protocol; generic parts
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 */
13#include <linux/kernel.h>
14#include <linux/rculist.h>
15
16#include "br_private.h"
17#include "br_private_stp.h"
18
19/* since time values in bpdu are in jiffies and then scaled (1/256)
20 * before sending, make sure that is at least one STP tick.
21 */
22#define MESSAGE_AGE_INCR ((HZ / 256) + 1)
23
24static const char *const br_port_state_names[] = {
25 [BR_STATE_DISABLED] = "disabled",
26 [BR_STATE_LISTENING] = "listening",
27 [BR_STATE_LEARNING] = "learning",
28 [BR_STATE_FORWARDING] = "forwarding",
29 [BR_STATE_BLOCKING] = "blocking",
30};
31
32void br_log_state(const struct net_bridge_port *p)
33{
34 br_info(p->br, "port %u(%s) entered %s state\n",
35 (unsigned int) p->port_no, p->dev->name,
36 br_port_state_names[p->state]);
37}
38
39/* called under bridge lock */
40struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
41{
42 struct net_bridge_port *p;
43
44 list_for_each_entry_rcu(p, &br->port_list, list) {
45 if (p->port_no == port_no)
46 return p;
47 }
48
49 return NULL;
50}
51
52/* called under bridge lock */
53static int br_should_become_root_port(const struct net_bridge_port *p,
54 u16 root_port)
55{
56 struct net_bridge *br;
57 struct net_bridge_port *rp;
58 int t;
59
60 br = p->br;
61 if (p->state == BR_STATE_DISABLED ||
62 br_is_designated_port(p))
63 return 0;
64
65 if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
66 return 0;
67
68 if (!root_port)
69 return 1;
70
71 rp = br_get_port(br, root_port);
72
73 t = memcmp(&p->designated_root, &rp->designated_root, 8);
74 if (t < 0)
75 return 1;
76 else if (t > 0)
77 return 0;
78
79 if (p->designated_cost + p->path_cost <
80 rp->designated_cost + rp->path_cost)
81 return 1;
82 else if (p->designated_cost + p->path_cost >
83 rp->designated_cost + rp->path_cost)
84 return 0;
85
86 t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
87 if (t < 0)
88 return 1;
89 else if (t > 0)
90 return 0;
91
92 if (p->designated_port < rp->designated_port)
93 return 1;
94 else if (p->designated_port > rp->designated_port)
95 return 0;
96
97 if (p->port_id < rp->port_id)
98 return 1;
99
100 return 0;
101}
102
103/* called under bridge lock */
104static void br_root_selection(struct net_bridge *br)
105{
106 struct net_bridge_port *p;
107 u16 root_port = 0;
108
109 list_for_each_entry(p, &br->port_list, list) {
110 if (br_should_become_root_port(p, root_port))
111 root_port = p->port_no;
112 }
113
114 br->root_port = root_port;
115
116 if (!root_port) {
117 br->designated_root = br->bridge_id;
118 br->root_path_cost = 0;
119 } else {
120 p = br_get_port(br, root_port);
121 br->designated_root = p->designated_root;
122 br->root_path_cost = p->designated_cost + p->path_cost;
123 }
124}
125
126/* called under bridge lock */
127void br_become_root_bridge(struct net_bridge *br)
128{
129 br->max_age = br->bridge_max_age;
130 br->hello_time = br->bridge_hello_time;
131 br->forward_delay = br->bridge_forward_delay;
132 br_topology_change_detection(br);
133 del_timer(&br->tcn_timer);
134
135 if (br->dev->flags & IFF_UP) {
136 br_config_bpdu_generation(br);
137 mod_timer(&br->hello_timer, jiffies + br->hello_time);
138 }
139}
140
141/* called under bridge lock */
142void br_transmit_config(struct net_bridge_port *p)
143{
144 struct br_config_bpdu bpdu;
145 struct net_bridge *br;
146
147 if (timer_pending(&p->hold_timer)) {
148 p->config_pending = 1;
149 return;
150 }
151
152 br = p->br;
153
154 bpdu.topology_change = br->topology_change;
155 bpdu.topology_change_ack = p->topology_change_ack;
156 bpdu.root = br->designated_root;
157 bpdu.root_path_cost = br->root_path_cost;
158 bpdu.bridge_id = br->bridge_id;
159 bpdu.port_id = p->port_id;
160 if (br_is_root_bridge(br))
161 bpdu.message_age = 0;
162 else {
163 struct net_bridge_port *root
164 = br_get_port(br, br->root_port);
165 bpdu.message_age = (jiffies - root->designated_age)
166 + MESSAGE_AGE_INCR;
167 }
168 bpdu.max_age = br->max_age;
169 bpdu.hello_time = br->hello_time;
170 bpdu.forward_delay = br->forward_delay;
171
172 if (bpdu.message_age < br->max_age) {
173 br_send_config_bpdu(p, &bpdu);
174 p->topology_change_ack = 0;
175 p->config_pending = 0;
176 mod_timer(&p->hold_timer,
177 round_jiffies(jiffies + BR_HOLD_TIME));
178 }
179}
180
181/* called under bridge lock */
182static void br_record_config_information(struct net_bridge_port *p,
183 const struct br_config_bpdu *bpdu)
184{
185 p->designated_root = bpdu->root;
186 p->designated_cost = bpdu->root_path_cost;
187 p->designated_bridge = bpdu->bridge_id;
188 p->designated_port = bpdu->port_id;
189 p->designated_age = jiffies - bpdu->message_age;
190
191 mod_timer(&p->message_age_timer, jiffies
192 + (p->br->max_age - bpdu->message_age));
193}
194
195/* called under bridge lock */
196static void br_record_config_timeout_values(struct net_bridge *br,
197 const struct br_config_bpdu *bpdu)
198{
199 br->max_age = bpdu->max_age;
200 br->hello_time = bpdu->hello_time;
201 br->forward_delay = bpdu->forward_delay;
202 br->topology_change = bpdu->topology_change;
203}
204
205/* called under bridge lock */
206void br_transmit_tcn(struct net_bridge *br)
207{
208 br_send_tcn_bpdu(br_get_port(br, br->root_port));
209}
210
211/* called under bridge lock */
212static int br_should_become_designated_port(const struct net_bridge_port *p)
213{
214 struct net_bridge *br;
215 int t;
216
217 br = p->br;
218 if (br_is_designated_port(p))
219 return 1;
220
221 if (memcmp(&p->designated_root, &br->designated_root, 8))
222 return 1;
223
224 if (br->root_path_cost < p->designated_cost)
225 return 1;
226 else if (br->root_path_cost > p->designated_cost)
227 return 0;
228
229 t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
230 if (t < 0)
231 return 1;
232 else if (t > 0)
233 return 0;
234
235 if (p->port_id < p->designated_port)
236 return 1;
237
238 return 0;
239}
240
241/* called under bridge lock */
242static void br_designated_port_selection(struct net_bridge *br)
243{
244 struct net_bridge_port *p;
245
246 list_for_each_entry(p, &br->port_list, list) {
247 if (p->state != BR_STATE_DISABLED &&
248 br_should_become_designated_port(p))
249 br_become_designated_port(p);
250
251 }
252}
253
254/* called under bridge lock */
255static int br_supersedes_port_info(const struct net_bridge_port *p,
256 const struct br_config_bpdu *bpdu)
257{
258 int t;
259
260 t = memcmp(&bpdu->root, &p->designated_root, 8);
261 if (t < 0)
262 return 1;
263 else if (t > 0)
264 return 0;
265
266 if (bpdu->root_path_cost < p->designated_cost)
267 return 1;
268 else if (bpdu->root_path_cost > p->designated_cost)
269 return 0;
270
271 t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
272 if (t < 0)
273 return 1;
274 else if (t > 0)
275 return 0;
276
277 if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
278 return 1;
279
280 if (bpdu->port_id <= p->designated_port)
281 return 1;
282
283 return 0;
284}
285
286/* called under bridge lock */
287static void br_topology_change_acknowledged(struct net_bridge *br)
288{
289 br->topology_change_detected = 0;
290 del_timer(&br->tcn_timer);
291}
292
293/* called under bridge lock */
294void br_topology_change_detection(struct net_bridge *br)
295{
296 int isroot = br_is_root_bridge(br);
297
298 if (br->stp_enabled != BR_KERNEL_STP)
299 return;
300
301 br_info(br, "topology change detected, %s\n",
302 isroot ? "propagating" : "sending tcn bpdu");
303
304 if (isroot) {
305 br->topology_change = 1;
306 mod_timer(&br->topology_change_timer, jiffies
307 + br->bridge_forward_delay + br->bridge_max_age);
308 } else if (!br->topology_change_detected) {
309 br_transmit_tcn(br);
310 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
311 }
312
313 br->topology_change_detected = 1;
314}
315
316/* called under bridge lock */
317void br_config_bpdu_generation(struct net_bridge *br)
318{
319 struct net_bridge_port *p;
320
321 list_for_each_entry(p, &br->port_list, list) {
322 if (p->state != BR_STATE_DISABLED &&
323 br_is_designated_port(p))
324 br_transmit_config(p);
325 }
326}
327
328/* called under bridge lock */
329static void br_reply(struct net_bridge_port *p)
330{
331 br_transmit_config(p);
332}
333
334/* called under bridge lock */
335void br_configuration_update(struct net_bridge *br)
336{
337 br_root_selection(br);
338 br_designated_port_selection(br);
339}
340
341/* called under bridge lock */
342void br_become_designated_port(struct net_bridge_port *p)
343{
344 struct net_bridge *br;
345
346 br = p->br;
347 p->designated_root = br->designated_root;
348 p->designated_cost = br->root_path_cost;
349 p->designated_bridge = br->bridge_id;
350 p->designated_port = p->port_id;
351}
352
353
354/* called under bridge lock */
355static void br_make_blocking(struct net_bridge_port *p)
356{
357 if (p->state != BR_STATE_DISABLED &&
358 p->state != BR_STATE_BLOCKING) {
359 if (p->state == BR_STATE_FORWARDING ||
360 p->state == BR_STATE_LEARNING)
361 br_topology_change_detection(p->br);
362
363 p->state = BR_STATE_BLOCKING;
364 br_log_state(p);
365 br_ifinfo_notify(RTM_NEWLINK, p);
366
367 del_timer(&p->forward_delay_timer);
368 }
369}
370
371/* called under bridge lock */
372static void br_make_forwarding(struct net_bridge_port *p)
373{
374 struct net_bridge *br = p->br;
375
376 if (p->state != BR_STATE_BLOCKING)
377 return;
378
379 if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
380 p->state = BR_STATE_FORWARDING;
381 br_topology_change_detection(br);
382 del_timer(&p->forward_delay_timer);
383 } else if (br->stp_enabled == BR_KERNEL_STP)
384 p->state = BR_STATE_LISTENING;
385 else
386 p->state = BR_STATE_LEARNING;
387
388 br_multicast_enable_port(p);
389 br_log_state(p);
390 br_ifinfo_notify(RTM_NEWLINK, p);
391
392 if (br->forward_delay != 0)
393 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
394}
395
396/* called under bridge lock */
397void br_port_state_selection(struct net_bridge *br)
398{
399 struct net_bridge_port *p;
400 unsigned int liveports = 0;
401
402 list_for_each_entry(p, &br->port_list, list) {
403 if (p->state == BR_STATE_DISABLED)
404 continue;
405
406 /* Don't change port states if userspace is handling STP */
407 if (br->stp_enabled != BR_USER_STP) {
408 if (p->port_no == br->root_port) {
409 p->config_pending = 0;
410 p->topology_change_ack = 0;
411 br_make_forwarding(p);
412 } else if (br_is_designated_port(p)) {
413 del_timer(&p->message_age_timer);
414 br_make_forwarding(p);
415 } else {
416 p->config_pending = 0;
417 p->topology_change_ack = 0;
418 br_make_blocking(p);
419 }
420 }
421
422 if (p->state == BR_STATE_FORWARDING)
423 ++liveports;
424 }
425
426 if (liveports == 0)
427 netif_carrier_off(br->dev);
428 else
429 netif_carrier_on(br->dev);
430}
431
432/* called under bridge lock */
433static void br_topology_change_acknowledge(struct net_bridge_port *p)
434{
435 p->topology_change_ack = 1;
436 br_transmit_config(p);
437}
438
439/* called under bridge lock */
440void br_received_config_bpdu(struct net_bridge_port *p,
441 const struct br_config_bpdu *bpdu)
442{
443 struct net_bridge *br;
444 int was_root;
445
446 br = p->br;
447 was_root = br_is_root_bridge(br);
448
449 if (br_supersedes_port_info(p, bpdu)) {
450 br_record_config_information(p, bpdu);
451 br_configuration_update(br);
452 br_port_state_selection(br);
453
454 if (!br_is_root_bridge(br) && was_root) {
455 del_timer(&br->hello_timer);
456 if (br->topology_change_detected) {
457 del_timer(&br->topology_change_timer);
458 br_transmit_tcn(br);
459
460 mod_timer(&br->tcn_timer,
461 jiffies + br->bridge_hello_time);
462 }
463 }
464
465 if (p->port_no == br->root_port) {
466 br_record_config_timeout_values(br, bpdu);
467 br_config_bpdu_generation(br);
468 if (bpdu->topology_change_ack)
469 br_topology_change_acknowledged(br);
470 }
471 } else if (br_is_designated_port(p)) {
472 br_reply(p);
473 }
474}
475
476/* called under bridge lock */
477void br_received_tcn_bpdu(struct net_bridge_port *p)
478{
479 if (br_is_designated_port(p)) {
480 br_info(p->br, "port %u(%s) received tcn bpdu\n",
481 (unsigned int) p->port_no, p->dev->name);
482
483 br_topology_change_detection(p->br);
484 br_topology_change_acknowledge(p);
485 }
486}
487
488/* Change bridge STP parameter */
489int br_set_hello_time(struct net_bridge *br, unsigned long val)
490{
491 unsigned long t = clock_t_to_jiffies(val);
492
493 if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
494 return -ERANGE;
495
496 spin_lock_bh(&br->lock);
497 br->bridge_hello_time = t;
498 if (br_is_root_bridge(br))
499 br->hello_time = br->bridge_hello_time;
500 spin_unlock_bh(&br->lock);
501 return 0;
502}
503
504int br_set_max_age(struct net_bridge *br, unsigned long val)
505{
506 unsigned long t = clock_t_to_jiffies(val);
507
508 if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
509 return -ERANGE;
510
511 spin_lock_bh(&br->lock);
512 br->bridge_max_age = t;
513 if (br_is_root_bridge(br))
514 br->max_age = br->bridge_max_age;
515 spin_unlock_bh(&br->lock);
516 return 0;
517
518}
519
520int br_set_forward_delay(struct net_bridge *br, unsigned long val)
521{
522 unsigned long t = clock_t_to_jiffies(val);
523
524 if (br->stp_enabled != BR_NO_STP &&
525 (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
526 return -ERANGE;
527
528 spin_lock_bh(&br->lock);
529 br->bridge_forward_delay = t;
530 if (br_is_root_bridge(br))
531 br->forward_delay = br->bridge_forward_delay;
532 spin_unlock_bh(&br->lock);
533 return 0;
534}