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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
103static void br_root_port_block(const struct net_bridge *br,
104 struct net_bridge_port *p)
105{
106
107 br_notice(br, "port %u(%s) tried to become root port (blocked)",
108 (unsigned int) p->port_no, p->dev->name);
109
110 p->state = BR_STATE_LISTENING;
111 br_log_state(p);
112 br_ifinfo_notify(RTM_NEWLINK, p);
113
114 if (br->forward_delay > 0)
115 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
116}
117
118/* called under bridge lock */
119static void br_root_selection(struct net_bridge *br)
120{
121 struct net_bridge_port *p;
122 u16 root_port = 0;
123
124 list_for_each_entry(p, &br->port_list, list) {
125 if (!br_should_become_root_port(p, root_port))
126 continue;
127
128 if (p->flags & BR_ROOT_BLOCK)
129 br_root_port_block(br, p);
130 else
131 root_port = p->port_no;
132 }
133
134 br->root_port = root_port;
135
136 if (!root_port) {
137 br->designated_root = br->bridge_id;
138 br->root_path_cost = 0;
139 } else {
140 p = br_get_port(br, root_port);
141 br->designated_root = p->designated_root;
142 br->root_path_cost = p->designated_cost + p->path_cost;
143 }
144}
145
146/* called under bridge lock */
147void br_become_root_bridge(struct net_bridge *br)
148{
149 br->max_age = br->bridge_max_age;
150 br->hello_time = br->bridge_hello_time;
151 br->forward_delay = br->bridge_forward_delay;
152 br_topology_change_detection(br);
153 del_timer(&br->tcn_timer);
154
155 if (br->dev->flags & IFF_UP) {
156 br_config_bpdu_generation(br);
157 mod_timer(&br->hello_timer, jiffies + br->hello_time);
158 }
159}
160
161/* called under bridge lock */
162void br_transmit_config(struct net_bridge_port *p)
163{
164 struct br_config_bpdu bpdu;
165 struct net_bridge *br;
166
167 if (timer_pending(&p->hold_timer)) {
168 p->config_pending = 1;
169 return;
170 }
171
172 br = p->br;
173
174 bpdu.topology_change = br->topology_change;
175 bpdu.topology_change_ack = p->topology_change_ack;
176 bpdu.root = br->designated_root;
177 bpdu.root_path_cost = br->root_path_cost;
178 bpdu.bridge_id = br->bridge_id;
179 bpdu.port_id = p->port_id;
180 if (br_is_root_bridge(br))
181 bpdu.message_age = 0;
182 else {
183 struct net_bridge_port *root
184 = br_get_port(br, br->root_port);
185 bpdu.message_age = (jiffies - root->designated_age)
186 + MESSAGE_AGE_INCR;
187 }
188 bpdu.max_age = br->max_age;
189 bpdu.hello_time = br->hello_time;
190 bpdu.forward_delay = br->forward_delay;
191
192 if (bpdu.message_age < br->max_age) {
193 br_send_config_bpdu(p, &bpdu);
194 p->topology_change_ack = 0;
195 p->config_pending = 0;
196 mod_timer(&p->hold_timer,
197 round_jiffies(jiffies + BR_HOLD_TIME));
198 }
199}
200
201/* called under bridge lock */
202static void br_record_config_information(struct net_bridge_port *p,
203 const struct br_config_bpdu *bpdu)
204{
205 p->designated_root = bpdu->root;
206 p->designated_cost = bpdu->root_path_cost;
207 p->designated_bridge = bpdu->bridge_id;
208 p->designated_port = bpdu->port_id;
209 p->designated_age = jiffies - bpdu->message_age;
210
211 mod_timer(&p->message_age_timer, jiffies
212 + (bpdu->max_age - bpdu->message_age));
213}
214
215/* called under bridge lock */
216static void br_record_config_timeout_values(struct net_bridge *br,
217 const struct br_config_bpdu *bpdu)
218{
219 br->max_age = bpdu->max_age;
220 br->hello_time = bpdu->hello_time;
221 br->forward_delay = bpdu->forward_delay;
222 br->topology_change = bpdu->topology_change;
223}
224
225/* called under bridge lock */
226void br_transmit_tcn(struct net_bridge *br)
227{
228 struct net_bridge_port *p;
229
230 p = br_get_port(br, br->root_port);
231 if (p)
232 br_send_tcn_bpdu(p);
233 else
234 br_notice(br, "root port %u not found for topology notice\n",
235 br->root_port);
236}
237
238/* called under bridge lock */
239static int br_should_become_designated_port(const struct net_bridge_port *p)
240{
241 struct net_bridge *br;
242 int t;
243
244 br = p->br;
245 if (br_is_designated_port(p))
246 return 1;
247
248 if (memcmp(&p->designated_root, &br->designated_root, 8))
249 return 1;
250
251 if (br->root_path_cost < p->designated_cost)
252 return 1;
253 else if (br->root_path_cost > p->designated_cost)
254 return 0;
255
256 t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
257 if (t < 0)
258 return 1;
259 else if (t > 0)
260 return 0;
261
262 if (p->port_id < p->designated_port)
263 return 1;
264
265 return 0;
266}
267
268/* called under bridge lock */
269static void br_designated_port_selection(struct net_bridge *br)
270{
271 struct net_bridge_port *p;
272
273 list_for_each_entry(p, &br->port_list, list) {
274 if (p->state != BR_STATE_DISABLED &&
275 br_should_become_designated_port(p))
276 br_become_designated_port(p);
277
278 }
279}
280
281/* called under bridge lock */
282static int br_supersedes_port_info(const struct net_bridge_port *p,
283 const struct br_config_bpdu *bpdu)
284{
285 int t;
286
287 t = memcmp(&bpdu->root, &p->designated_root, 8);
288 if (t < 0)
289 return 1;
290 else if (t > 0)
291 return 0;
292
293 if (bpdu->root_path_cost < p->designated_cost)
294 return 1;
295 else if (bpdu->root_path_cost > p->designated_cost)
296 return 0;
297
298 t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
299 if (t < 0)
300 return 1;
301 else if (t > 0)
302 return 0;
303
304 if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
305 return 1;
306
307 if (bpdu->port_id <= p->designated_port)
308 return 1;
309
310 return 0;
311}
312
313/* called under bridge lock */
314static void br_topology_change_acknowledged(struct net_bridge *br)
315{
316 br->topology_change_detected = 0;
317 del_timer(&br->tcn_timer);
318}
319
320/* called under bridge lock */
321void br_topology_change_detection(struct net_bridge *br)
322{
323 int isroot = br_is_root_bridge(br);
324
325 if (br->stp_enabled != BR_KERNEL_STP)
326 return;
327
328 br_info(br, "topology change detected, %s\n",
329 isroot ? "propagating" : "sending tcn bpdu");
330
331 if (isroot) {
332 br->topology_change = 1;
333 mod_timer(&br->topology_change_timer, jiffies
334 + br->bridge_forward_delay + br->bridge_max_age);
335 } else if (!br->topology_change_detected) {
336 br_transmit_tcn(br);
337 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
338 }
339
340 br->topology_change_detected = 1;
341}
342
343/* called under bridge lock */
344void br_config_bpdu_generation(struct net_bridge *br)
345{
346 struct net_bridge_port *p;
347
348 list_for_each_entry(p, &br->port_list, list) {
349 if (p->state != BR_STATE_DISABLED &&
350 br_is_designated_port(p))
351 br_transmit_config(p);
352 }
353}
354
355/* called under bridge lock */
356static void br_reply(struct net_bridge_port *p)
357{
358 br_transmit_config(p);
359}
360
361/* called under bridge lock */
362void br_configuration_update(struct net_bridge *br)
363{
364 br_root_selection(br);
365 br_designated_port_selection(br);
366}
367
368/* called under bridge lock */
369void br_become_designated_port(struct net_bridge_port *p)
370{
371 struct net_bridge *br;
372
373 br = p->br;
374 p->designated_root = br->designated_root;
375 p->designated_cost = br->root_path_cost;
376 p->designated_bridge = br->bridge_id;
377 p->designated_port = p->port_id;
378}
379
380
381/* called under bridge lock */
382static void br_make_blocking(struct net_bridge_port *p)
383{
384 if (p->state != BR_STATE_DISABLED &&
385 p->state != BR_STATE_BLOCKING) {
386 if (p->state == BR_STATE_FORWARDING ||
387 p->state == BR_STATE_LEARNING)
388 br_topology_change_detection(p->br);
389
390 p->state = BR_STATE_BLOCKING;
391 br_log_state(p);
392 br_ifinfo_notify(RTM_NEWLINK, p);
393
394 del_timer(&p->forward_delay_timer);
395 }
396}
397
398/* called under bridge lock */
399static void br_make_forwarding(struct net_bridge_port *p)
400{
401 struct net_bridge *br = p->br;
402
403 if (p->state != BR_STATE_BLOCKING)
404 return;
405
406 if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
407 p->state = BR_STATE_FORWARDING;
408 br_topology_change_detection(br);
409 del_timer(&p->forward_delay_timer);
410 } else if (br->stp_enabled == BR_KERNEL_STP)
411 p->state = BR_STATE_LISTENING;
412 else
413 p->state = BR_STATE_LEARNING;
414
415 br_multicast_enable_port(p);
416 br_log_state(p);
417 br_ifinfo_notify(RTM_NEWLINK, p);
418
419 if (br->forward_delay != 0)
420 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
421}
422
423/* called under bridge lock */
424void br_port_state_selection(struct net_bridge *br)
425{
426 struct net_bridge_port *p;
427 unsigned int liveports = 0;
428
429 list_for_each_entry(p, &br->port_list, list) {
430 if (p->state == BR_STATE_DISABLED)
431 continue;
432
433 /* Don't change port states if userspace is handling STP */
434 if (br->stp_enabled != BR_USER_STP) {
435 if (p->port_no == br->root_port) {
436 p->config_pending = 0;
437 p->topology_change_ack = 0;
438 br_make_forwarding(p);
439 } else if (br_is_designated_port(p)) {
440 del_timer(&p->message_age_timer);
441 br_make_forwarding(p);
442 } else {
443 p->config_pending = 0;
444 p->topology_change_ack = 0;
445 br_make_blocking(p);
446 }
447 }
448
449 if (p->state == BR_STATE_FORWARDING)
450 ++liveports;
451 }
452
453 if (liveports == 0)
454 netif_carrier_off(br->dev);
455 else
456 netif_carrier_on(br->dev);
457}
458
459/* called under bridge lock */
460static void br_topology_change_acknowledge(struct net_bridge_port *p)
461{
462 p->topology_change_ack = 1;
463 br_transmit_config(p);
464}
465
466/* called under bridge lock */
467void br_received_config_bpdu(struct net_bridge_port *p,
468 const struct br_config_bpdu *bpdu)
469{
470 struct net_bridge *br;
471 int was_root;
472
473 br = p->br;
474 was_root = br_is_root_bridge(br);
475
476 if (br_supersedes_port_info(p, bpdu)) {
477 br_record_config_information(p, bpdu);
478 br_configuration_update(br);
479 br_port_state_selection(br);
480
481 if (!br_is_root_bridge(br) && was_root) {
482 del_timer(&br->hello_timer);
483 if (br->topology_change_detected) {
484 del_timer(&br->topology_change_timer);
485 br_transmit_tcn(br);
486
487 mod_timer(&br->tcn_timer,
488 jiffies + br->bridge_hello_time);
489 }
490 }
491
492 if (p->port_no == br->root_port) {
493 br_record_config_timeout_values(br, bpdu);
494 br_config_bpdu_generation(br);
495 if (bpdu->topology_change_ack)
496 br_topology_change_acknowledged(br);
497 }
498 } else if (br_is_designated_port(p)) {
499 br_reply(p);
500 }
501}
502
503/* called under bridge lock */
504void br_received_tcn_bpdu(struct net_bridge_port *p)
505{
506 if (br_is_designated_port(p)) {
507 br_info(p->br, "port %u(%s) received tcn bpdu\n",
508 (unsigned int) p->port_no, p->dev->name);
509
510 br_topology_change_detection(p->br);
511 br_topology_change_acknowledge(p);
512 }
513}
514
515/* Change bridge STP parameter */
516int br_set_hello_time(struct net_bridge *br, unsigned long val)
517{
518 unsigned long t = clock_t_to_jiffies(val);
519
520 if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
521 return -ERANGE;
522
523 spin_lock_bh(&br->lock);
524 br->bridge_hello_time = t;
525 if (br_is_root_bridge(br))
526 br->hello_time = br->bridge_hello_time;
527 spin_unlock_bh(&br->lock);
528 return 0;
529}
530
531int br_set_max_age(struct net_bridge *br, unsigned long val)
532{
533 unsigned long t = clock_t_to_jiffies(val);
534
535 if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
536 return -ERANGE;
537
538 spin_lock_bh(&br->lock);
539 br->bridge_max_age = t;
540 if (br_is_root_bridge(br))
541 br->max_age = br->bridge_max_age;
542 spin_unlock_bh(&br->lock);
543 return 0;
544
545}
546
547void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
548{
549 br->bridge_forward_delay = t;
550 if (br_is_root_bridge(br))
551 br->forward_delay = br->bridge_forward_delay;
552}
553
554int br_set_forward_delay(struct net_bridge *br, unsigned long val)
555{
556 unsigned long t = clock_t_to_jiffies(val);
557 int err = -ERANGE;
558
559 spin_lock_bh(&br->lock);
560 if (br->stp_enabled != BR_NO_STP &&
561 (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
562 goto unlock;
563
564 __br_set_forward_delay(br, t);
565 err = 0;
566
567unlock:
568 spin_unlock_bh(&br->lock);
569 return err;
570}