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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#include <net/switchdev.h>
16
17#include "br_private.h"
18#include "br_private_stp.h"
19
20/* since time values in bpdu are in jiffies and then scaled (1/256)
21 * before sending, make sure that is at least one STP tick.
22 */
23#define MESSAGE_AGE_INCR ((HZ / 256) + 1)
24
25static const char *const br_port_state_names[] = {
26 [BR_STATE_DISABLED] = "disabled",
27 [BR_STATE_LISTENING] = "listening",
28 [BR_STATE_LEARNING] = "learning",
29 [BR_STATE_FORWARDING] = "forwarding",
30 [BR_STATE_BLOCKING] = "blocking",
31};
32
33void br_set_state(struct net_bridge_port *p, unsigned int state)
34{
35 struct switchdev_attr attr = {
36 .orig_dev = p->dev,
37 .id = SWITCHDEV_ATTR_ID_PORT_STP_STATE,
38 .flags = SWITCHDEV_F_DEFER,
39 .u.stp_state = state,
40 };
41 int err;
42
43 p->state = state;
44 err = switchdev_port_attr_set(p->dev, &attr);
45 if (err && err != -EOPNOTSUPP)
46 br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
47 (unsigned int) p->port_no, p->dev->name);
48 else
49 br_info(p->br, "port %u(%s) entered %s state\n",
50 (unsigned int) p->port_no, p->dev->name,
51 br_port_state_names[p->state]);
52}
53
54/* called under bridge lock */
55struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
56{
57 struct net_bridge_port *p;
58
59 list_for_each_entry_rcu(p, &br->port_list, list) {
60 if (p->port_no == port_no)
61 return p;
62 }
63
64 return NULL;
65}
66
67/* called under bridge lock */
68static int br_should_become_root_port(const struct net_bridge_port *p,
69 u16 root_port)
70{
71 struct net_bridge *br;
72 struct net_bridge_port *rp;
73 int t;
74
75 br = p->br;
76 if (p->state == BR_STATE_DISABLED ||
77 br_is_designated_port(p))
78 return 0;
79
80 if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
81 return 0;
82
83 if (!root_port)
84 return 1;
85
86 rp = br_get_port(br, root_port);
87
88 t = memcmp(&p->designated_root, &rp->designated_root, 8);
89 if (t < 0)
90 return 1;
91 else if (t > 0)
92 return 0;
93
94 if (p->designated_cost + p->path_cost <
95 rp->designated_cost + rp->path_cost)
96 return 1;
97 else if (p->designated_cost + p->path_cost >
98 rp->designated_cost + rp->path_cost)
99 return 0;
100
101 t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
102 if (t < 0)
103 return 1;
104 else if (t > 0)
105 return 0;
106
107 if (p->designated_port < rp->designated_port)
108 return 1;
109 else if (p->designated_port > rp->designated_port)
110 return 0;
111
112 if (p->port_id < rp->port_id)
113 return 1;
114
115 return 0;
116}
117
118static void br_root_port_block(const struct net_bridge *br,
119 struct net_bridge_port *p)
120{
121
122 br_notice(br, "port %u(%s) tried to become root port (blocked)",
123 (unsigned int) p->port_no, p->dev->name);
124
125 br_set_state(p, BR_STATE_LISTENING);
126 br_ifinfo_notify(RTM_NEWLINK, p);
127
128 if (br->forward_delay > 0)
129 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
130}
131
132/* called under bridge lock */
133static void br_root_selection(struct net_bridge *br)
134{
135 struct net_bridge_port *p;
136 u16 root_port = 0;
137
138 list_for_each_entry(p, &br->port_list, list) {
139 if (!br_should_become_root_port(p, root_port))
140 continue;
141
142 if (p->flags & BR_ROOT_BLOCK)
143 br_root_port_block(br, p);
144 else
145 root_port = p->port_no;
146 }
147
148 br->root_port = root_port;
149
150 if (!root_port) {
151 br->designated_root = br->bridge_id;
152 br->root_path_cost = 0;
153 } else {
154 p = br_get_port(br, root_port);
155 br->designated_root = p->designated_root;
156 br->root_path_cost = p->designated_cost + p->path_cost;
157 }
158}
159
160/* called under bridge lock */
161void br_become_root_bridge(struct net_bridge *br)
162{
163 br->max_age = br->bridge_max_age;
164 br->hello_time = br->bridge_hello_time;
165 br->forward_delay = br->bridge_forward_delay;
166 br_topology_change_detection(br);
167 del_timer(&br->tcn_timer);
168
169 if (br->dev->flags & IFF_UP) {
170 br_config_bpdu_generation(br);
171 mod_timer(&br->hello_timer, jiffies + br->hello_time);
172 }
173}
174
175/* called under bridge lock */
176void br_transmit_config(struct net_bridge_port *p)
177{
178 struct br_config_bpdu bpdu;
179 struct net_bridge *br;
180
181 if (timer_pending(&p->hold_timer)) {
182 p->config_pending = 1;
183 return;
184 }
185
186 br = p->br;
187
188 bpdu.topology_change = br->topology_change;
189 bpdu.topology_change_ack = p->topology_change_ack;
190 bpdu.root = br->designated_root;
191 bpdu.root_path_cost = br->root_path_cost;
192 bpdu.bridge_id = br->bridge_id;
193 bpdu.port_id = p->port_id;
194 if (br_is_root_bridge(br))
195 bpdu.message_age = 0;
196 else {
197 struct net_bridge_port *root
198 = br_get_port(br, br->root_port);
199 bpdu.message_age = (jiffies - root->designated_age)
200 + MESSAGE_AGE_INCR;
201 }
202 bpdu.max_age = br->max_age;
203 bpdu.hello_time = br->hello_time;
204 bpdu.forward_delay = br->forward_delay;
205
206 if (bpdu.message_age < br->max_age) {
207 br_send_config_bpdu(p, &bpdu);
208 p->topology_change_ack = 0;
209 p->config_pending = 0;
210 if (p->br->stp_enabled == BR_KERNEL_STP)
211 mod_timer(&p->hold_timer,
212 round_jiffies(jiffies + BR_HOLD_TIME));
213 }
214}
215
216/* called under bridge lock */
217static void br_record_config_information(struct net_bridge_port *p,
218 const struct br_config_bpdu *bpdu)
219{
220 p->designated_root = bpdu->root;
221 p->designated_cost = bpdu->root_path_cost;
222 p->designated_bridge = bpdu->bridge_id;
223 p->designated_port = bpdu->port_id;
224 p->designated_age = jiffies - bpdu->message_age;
225
226 mod_timer(&p->message_age_timer, jiffies
227 + (bpdu->max_age - bpdu->message_age));
228}
229
230/* called under bridge lock */
231static void br_record_config_timeout_values(struct net_bridge *br,
232 const struct br_config_bpdu *bpdu)
233{
234 br->max_age = bpdu->max_age;
235 br->hello_time = bpdu->hello_time;
236 br->forward_delay = bpdu->forward_delay;
237 br->topology_change = bpdu->topology_change;
238}
239
240/* called under bridge lock */
241void br_transmit_tcn(struct net_bridge *br)
242{
243 struct net_bridge_port *p;
244
245 p = br_get_port(br, br->root_port);
246 if (p)
247 br_send_tcn_bpdu(p);
248 else
249 br_notice(br, "root port %u not found for topology notice\n",
250 br->root_port);
251}
252
253/* called under bridge lock */
254static int br_should_become_designated_port(const struct net_bridge_port *p)
255{
256 struct net_bridge *br;
257 int t;
258
259 br = p->br;
260 if (br_is_designated_port(p))
261 return 1;
262
263 if (memcmp(&p->designated_root, &br->designated_root, 8))
264 return 1;
265
266 if (br->root_path_cost < p->designated_cost)
267 return 1;
268 else if (br->root_path_cost > p->designated_cost)
269 return 0;
270
271 t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
272 if (t < 0)
273 return 1;
274 else if (t > 0)
275 return 0;
276
277 if (p->port_id < p->designated_port)
278 return 1;
279
280 return 0;
281}
282
283/* called under bridge lock */
284static void br_designated_port_selection(struct net_bridge *br)
285{
286 struct net_bridge_port *p;
287
288 list_for_each_entry(p, &br->port_list, list) {
289 if (p->state != BR_STATE_DISABLED &&
290 br_should_become_designated_port(p))
291 br_become_designated_port(p);
292
293 }
294}
295
296/* called under bridge lock */
297static int br_supersedes_port_info(const struct net_bridge_port *p,
298 const struct br_config_bpdu *bpdu)
299{
300 int t;
301
302 t = memcmp(&bpdu->root, &p->designated_root, 8);
303 if (t < 0)
304 return 1;
305 else if (t > 0)
306 return 0;
307
308 if (bpdu->root_path_cost < p->designated_cost)
309 return 1;
310 else if (bpdu->root_path_cost > p->designated_cost)
311 return 0;
312
313 t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
314 if (t < 0)
315 return 1;
316 else if (t > 0)
317 return 0;
318
319 if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
320 return 1;
321
322 if (bpdu->port_id <= p->designated_port)
323 return 1;
324
325 return 0;
326}
327
328/* called under bridge lock */
329static void br_topology_change_acknowledged(struct net_bridge *br)
330{
331 br->topology_change_detected = 0;
332 del_timer(&br->tcn_timer);
333}
334
335/* called under bridge lock */
336void br_topology_change_detection(struct net_bridge *br)
337{
338 int isroot = br_is_root_bridge(br);
339
340 if (br->stp_enabled != BR_KERNEL_STP)
341 return;
342
343 br_info(br, "topology change detected, %s\n",
344 isroot ? "propagating" : "sending tcn bpdu");
345
346 if (isroot) {
347 br->topology_change = 1;
348 mod_timer(&br->topology_change_timer, jiffies
349 + br->bridge_forward_delay + br->bridge_max_age);
350 } else if (!br->topology_change_detected) {
351 br_transmit_tcn(br);
352 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
353 }
354
355 br->topology_change_detected = 1;
356}
357
358/* called under bridge lock */
359void br_config_bpdu_generation(struct net_bridge *br)
360{
361 struct net_bridge_port *p;
362
363 list_for_each_entry(p, &br->port_list, list) {
364 if (p->state != BR_STATE_DISABLED &&
365 br_is_designated_port(p))
366 br_transmit_config(p);
367 }
368}
369
370/* called under bridge lock */
371static void br_reply(struct net_bridge_port *p)
372{
373 br_transmit_config(p);
374}
375
376/* called under bridge lock */
377void br_configuration_update(struct net_bridge *br)
378{
379 br_root_selection(br);
380 br_designated_port_selection(br);
381}
382
383/* called under bridge lock */
384void br_become_designated_port(struct net_bridge_port *p)
385{
386 struct net_bridge *br;
387
388 br = p->br;
389 p->designated_root = br->designated_root;
390 p->designated_cost = br->root_path_cost;
391 p->designated_bridge = br->bridge_id;
392 p->designated_port = p->port_id;
393}
394
395
396/* called under bridge lock */
397static void br_make_blocking(struct net_bridge_port *p)
398{
399 if (p->state != BR_STATE_DISABLED &&
400 p->state != BR_STATE_BLOCKING) {
401 if (p->state == BR_STATE_FORWARDING ||
402 p->state == BR_STATE_LEARNING)
403 br_topology_change_detection(p->br);
404
405 br_set_state(p, BR_STATE_BLOCKING);
406 br_ifinfo_notify(RTM_NEWLINK, p);
407
408 del_timer(&p->forward_delay_timer);
409 }
410}
411
412/* called under bridge lock */
413static void br_make_forwarding(struct net_bridge_port *p)
414{
415 struct net_bridge *br = p->br;
416
417 if (p->state != BR_STATE_BLOCKING)
418 return;
419
420 if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
421 br_set_state(p, BR_STATE_FORWARDING);
422 br_topology_change_detection(br);
423 del_timer(&p->forward_delay_timer);
424 } else if (br->stp_enabled == BR_KERNEL_STP)
425 br_set_state(p, BR_STATE_LISTENING);
426 else
427 br_set_state(p, BR_STATE_LEARNING);
428
429 br_ifinfo_notify(RTM_NEWLINK, p);
430
431 if (br->forward_delay != 0)
432 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
433}
434
435/* called under bridge lock */
436void br_port_state_selection(struct net_bridge *br)
437{
438 struct net_bridge_port *p;
439 unsigned int liveports = 0;
440
441 list_for_each_entry(p, &br->port_list, list) {
442 if (p->state == BR_STATE_DISABLED)
443 continue;
444
445 /* Don't change port states if userspace is handling STP */
446 if (br->stp_enabled != BR_USER_STP) {
447 if (p->port_no == br->root_port) {
448 p->config_pending = 0;
449 p->topology_change_ack = 0;
450 br_make_forwarding(p);
451 } else if (br_is_designated_port(p)) {
452 del_timer(&p->message_age_timer);
453 br_make_forwarding(p);
454 } else {
455 p->config_pending = 0;
456 p->topology_change_ack = 0;
457 br_make_blocking(p);
458 }
459 }
460
461 if (p->state != BR_STATE_BLOCKING)
462 br_multicast_enable_port(p);
463 /* Multicast is not disabled for the port when it goes in
464 * blocking state because the timers will expire and stop by
465 * themselves without sending more queries.
466 */
467 if (p->state == BR_STATE_FORWARDING)
468 ++liveports;
469 }
470
471 if (liveports == 0)
472 netif_carrier_off(br->dev);
473 else
474 netif_carrier_on(br->dev);
475}
476
477/* called under bridge lock */
478static void br_topology_change_acknowledge(struct net_bridge_port *p)
479{
480 p->topology_change_ack = 1;
481 br_transmit_config(p);
482}
483
484/* called under bridge lock */
485void br_received_config_bpdu(struct net_bridge_port *p,
486 const struct br_config_bpdu *bpdu)
487{
488 struct net_bridge *br;
489 int was_root;
490
491 br = p->br;
492 was_root = br_is_root_bridge(br);
493
494 if (br_supersedes_port_info(p, bpdu)) {
495 br_record_config_information(p, bpdu);
496 br_configuration_update(br);
497 br_port_state_selection(br);
498
499 if (!br_is_root_bridge(br) && was_root) {
500 del_timer(&br->hello_timer);
501 if (br->topology_change_detected) {
502 del_timer(&br->topology_change_timer);
503 br_transmit_tcn(br);
504
505 mod_timer(&br->tcn_timer,
506 jiffies + br->bridge_hello_time);
507 }
508 }
509
510 if (p->port_no == br->root_port) {
511 br_record_config_timeout_values(br, bpdu);
512 br_config_bpdu_generation(br);
513 if (bpdu->topology_change_ack)
514 br_topology_change_acknowledged(br);
515 }
516 } else if (br_is_designated_port(p)) {
517 br_reply(p);
518 }
519}
520
521/* called under bridge lock */
522void br_received_tcn_bpdu(struct net_bridge_port *p)
523{
524 if (br_is_designated_port(p)) {
525 br_info(p->br, "port %u(%s) received tcn bpdu\n",
526 (unsigned int) p->port_no, p->dev->name);
527
528 br_topology_change_detection(p->br);
529 br_topology_change_acknowledge(p);
530 }
531}
532
533/* Change bridge STP parameter */
534int br_set_hello_time(struct net_bridge *br, unsigned long val)
535{
536 unsigned long t = clock_t_to_jiffies(val);
537
538 if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
539 return -ERANGE;
540
541 spin_lock_bh(&br->lock);
542 br->bridge_hello_time = t;
543 if (br_is_root_bridge(br))
544 br->hello_time = br->bridge_hello_time;
545 spin_unlock_bh(&br->lock);
546 return 0;
547}
548
549int br_set_max_age(struct net_bridge *br, unsigned long val)
550{
551 unsigned long t = clock_t_to_jiffies(val);
552
553 if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
554 return -ERANGE;
555
556 spin_lock_bh(&br->lock);
557 br->bridge_max_age = t;
558 if (br_is_root_bridge(br))
559 br->max_age = br->bridge_max_age;
560 spin_unlock_bh(&br->lock);
561 return 0;
562
563}
564
565/* Set time interval that dynamic forwarding entries live
566 * For pure software bridge, allow values outside the 802.1
567 * standard specification for special cases:
568 * 0 - entry never ages (all permanant)
569 * 1 - entry disappears (no persistance)
570 *
571 * Offloaded switch entries maybe more restrictive
572 */
573int br_set_ageing_time(struct net_bridge *br, u32 ageing_time)
574{
575 struct switchdev_attr attr = {
576 .orig_dev = br->dev,
577 .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
578 .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP,
579 .u.ageing_time = ageing_time,
580 };
581 unsigned long t = clock_t_to_jiffies(ageing_time);
582 int err;
583
584 err = switchdev_port_attr_set(br->dev, &attr);
585 if (err && err != -EOPNOTSUPP)
586 return err;
587
588 br->ageing_time = t;
589 mod_timer(&br->gc_timer, jiffies);
590
591 return 0;
592}
593
594void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
595{
596 br->bridge_forward_delay = t;
597 if (br_is_root_bridge(br))
598 br->forward_delay = br->bridge_forward_delay;
599}
600
601int br_set_forward_delay(struct net_bridge *br, unsigned long val)
602{
603 unsigned long t = clock_t_to_jiffies(val);
604 int err = -ERANGE;
605
606 spin_lock_bh(&br->lock);
607 if (br->stp_enabled != BR_NO_STP &&
608 (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
609 goto unlock;
610
611 __br_set_forward_delay(br, t);
612 err = 0;
613
614unlock:
615 spin_unlock_bh(&br->lock);
616 return err;
617}
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}