Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Spanning tree protocol; generic parts
4 * Linux ethernet bridge
5 *
6 * Authors:
7 * Lennert Buytenhek <buytenh@gnu.org>
8 */
9#include <linux/kernel.h>
10#include <linux/rculist.h>
11#include <net/switchdev.h>
12
13#include "br_private.h"
14#include "br_private_stp.h"
15
16/* since time values in bpdu are in jiffies and then scaled (1/256)
17 * before sending, make sure that is at least one STP tick.
18 */
19#define MESSAGE_AGE_INCR ((HZ / 256) + 1)
20
21static const char *const br_port_state_names[] = {
22 [BR_STATE_DISABLED] = "disabled",
23 [BR_STATE_LISTENING] = "listening",
24 [BR_STATE_LEARNING] = "learning",
25 [BR_STATE_FORWARDING] = "forwarding",
26 [BR_STATE_BLOCKING] = "blocking",
27};
28
29void br_set_state(struct net_bridge_port *p, unsigned int state)
30{
31 struct switchdev_attr attr = {
32 .orig_dev = p->dev,
33 .id = SWITCHDEV_ATTR_ID_PORT_STP_STATE,
34 .flags = SWITCHDEV_F_DEFER,
35 .u.stp_state = state,
36 };
37 int err;
38
39 p->state = state;
40 err = switchdev_port_attr_set(p->dev, &attr);
41 if (err && err != -EOPNOTSUPP)
42 br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
43 (unsigned int) p->port_no, p->dev->name);
44 else
45 br_info(p->br, "port %u(%s) entered %s state\n",
46 (unsigned int) p->port_no, p->dev->name,
47 br_port_state_names[p->state]);
48}
49
50/* called under bridge lock */
51struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
52{
53 struct net_bridge_port *p;
54
55 list_for_each_entry_rcu(p, &br->port_list, list) {
56 if (p->port_no == port_no)
57 return p;
58 }
59
60 return NULL;
61}
62
63/* called under bridge lock */
64static int br_should_become_root_port(const struct net_bridge_port *p,
65 u16 root_port)
66{
67 struct net_bridge *br;
68 struct net_bridge_port *rp;
69 int t;
70
71 br = p->br;
72 if (p->state == BR_STATE_DISABLED ||
73 br_is_designated_port(p))
74 return 0;
75
76 if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
77 return 0;
78
79 if (!root_port)
80 return 1;
81
82 rp = br_get_port(br, root_port);
83
84 t = memcmp(&p->designated_root, &rp->designated_root, 8);
85 if (t < 0)
86 return 1;
87 else if (t > 0)
88 return 0;
89
90 if (p->designated_cost + p->path_cost <
91 rp->designated_cost + rp->path_cost)
92 return 1;
93 else if (p->designated_cost + p->path_cost >
94 rp->designated_cost + rp->path_cost)
95 return 0;
96
97 t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
98 if (t < 0)
99 return 1;
100 else if (t > 0)
101 return 0;
102
103 if (p->designated_port < rp->designated_port)
104 return 1;
105 else if (p->designated_port > rp->designated_port)
106 return 0;
107
108 if (p->port_id < rp->port_id)
109 return 1;
110
111 return 0;
112}
113
114static void br_root_port_block(const struct net_bridge *br,
115 struct net_bridge_port *p)
116{
117
118 br_notice(br, "port %u(%s) tried to become root port (blocked)",
119 (unsigned int) p->port_no, p->dev->name);
120
121 br_set_state(p, BR_STATE_LISTENING);
122 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
123
124 if (br->forward_delay > 0)
125 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
126}
127
128/* called under bridge lock */
129static void br_root_selection(struct net_bridge *br)
130{
131 struct net_bridge_port *p;
132 u16 root_port = 0;
133
134 list_for_each_entry(p, &br->port_list, list) {
135 if (!br_should_become_root_port(p, root_port))
136 continue;
137
138 if (p->flags & BR_ROOT_BLOCK)
139 br_root_port_block(br, p);
140 else
141 root_port = p->port_no;
142 }
143
144 br->root_port = root_port;
145
146 if (!root_port) {
147 br->designated_root = br->bridge_id;
148 br->root_path_cost = 0;
149 } else {
150 p = br_get_port(br, root_port);
151 br->designated_root = p->designated_root;
152 br->root_path_cost = p->designated_cost + p->path_cost;
153 }
154}
155
156/* called under bridge lock */
157void br_become_root_bridge(struct net_bridge *br)
158{
159 br->max_age = br->bridge_max_age;
160 br->hello_time = br->bridge_hello_time;
161 br->forward_delay = br->bridge_forward_delay;
162 br_topology_change_detection(br);
163 del_timer(&br->tcn_timer);
164
165 if (br->dev->flags & IFF_UP) {
166 br_config_bpdu_generation(br);
167 mod_timer(&br->hello_timer, jiffies + br->hello_time);
168 }
169}
170
171/* called under bridge lock */
172void br_transmit_config(struct net_bridge_port *p)
173{
174 struct br_config_bpdu bpdu;
175 struct net_bridge *br;
176
177 if (timer_pending(&p->hold_timer)) {
178 p->config_pending = 1;
179 return;
180 }
181
182 br = p->br;
183
184 bpdu.topology_change = br->topology_change;
185 bpdu.topology_change_ack = p->topology_change_ack;
186 bpdu.root = br->designated_root;
187 bpdu.root_path_cost = br->root_path_cost;
188 bpdu.bridge_id = br->bridge_id;
189 bpdu.port_id = p->port_id;
190 if (br_is_root_bridge(br))
191 bpdu.message_age = 0;
192 else {
193 struct net_bridge_port *root
194 = br_get_port(br, br->root_port);
195 bpdu.message_age = (jiffies - root->designated_age)
196 + MESSAGE_AGE_INCR;
197 }
198 bpdu.max_age = br->max_age;
199 bpdu.hello_time = br->hello_time;
200 bpdu.forward_delay = br->forward_delay;
201
202 if (bpdu.message_age < br->max_age) {
203 br_send_config_bpdu(p, &bpdu);
204 p->topology_change_ack = 0;
205 p->config_pending = 0;
206 if (p->br->stp_enabled == BR_KERNEL_STP)
207 mod_timer(&p->hold_timer,
208 round_jiffies(jiffies + BR_HOLD_TIME));
209 }
210}
211
212/* called under bridge lock */
213static void br_record_config_information(struct net_bridge_port *p,
214 const struct br_config_bpdu *bpdu)
215{
216 p->designated_root = bpdu->root;
217 p->designated_cost = bpdu->root_path_cost;
218 p->designated_bridge = bpdu->bridge_id;
219 p->designated_port = bpdu->port_id;
220 p->designated_age = jiffies - bpdu->message_age;
221
222 mod_timer(&p->message_age_timer, jiffies
223 + (bpdu->max_age - bpdu->message_age));
224}
225
226/* called under bridge lock */
227static void br_record_config_timeout_values(struct net_bridge *br,
228 const struct br_config_bpdu *bpdu)
229{
230 br->max_age = bpdu->max_age;
231 br->hello_time = bpdu->hello_time;
232 br->forward_delay = bpdu->forward_delay;
233 __br_set_topology_change(br, bpdu->topology_change);
234}
235
236/* called under bridge lock */
237void br_transmit_tcn(struct net_bridge *br)
238{
239 struct net_bridge_port *p;
240
241 p = br_get_port(br, br->root_port);
242 if (p)
243 br_send_tcn_bpdu(p);
244 else
245 br_notice(br, "root port %u not found for topology notice\n",
246 br->root_port);
247}
248
249/* called under bridge lock */
250static int br_should_become_designated_port(const struct net_bridge_port *p)
251{
252 struct net_bridge *br;
253 int t;
254
255 br = p->br;
256 if (br_is_designated_port(p))
257 return 1;
258
259 if (memcmp(&p->designated_root, &br->designated_root, 8))
260 return 1;
261
262 if (br->root_path_cost < p->designated_cost)
263 return 1;
264 else if (br->root_path_cost > p->designated_cost)
265 return 0;
266
267 t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
268 if (t < 0)
269 return 1;
270 else if (t > 0)
271 return 0;
272
273 if (p->port_id < p->designated_port)
274 return 1;
275
276 return 0;
277}
278
279/* called under bridge lock */
280static void br_designated_port_selection(struct net_bridge *br)
281{
282 struct net_bridge_port *p;
283
284 list_for_each_entry(p, &br->port_list, list) {
285 if (p->state != BR_STATE_DISABLED &&
286 br_should_become_designated_port(p))
287 br_become_designated_port(p);
288
289 }
290}
291
292/* called under bridge lock */
293static int br_supersedes_port_info(const struct net_bridge_port *p,
294 const struct br_config_bpdu *bpdu)
295{
296 int t;
297
298 t = memcmp(&bpdu->root, &p->designated_root, 8);
299 if (t < 0)
300 return 1;
301 else if (t > 0)
302 return 0;
303
304 if (bpdu->root_path_cost < p->designated_cost)
305 return 1;
306 else if (bpdu->root_path_cost > p->designated_cost)
307 return 0;
308
309 t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
310 if (t < 0)
311 return 1;
312 else if (t > 0)
313 return 0;
314
315 if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
316 return 1;
317
318 if (bpdu->port_id <= p->designated_port)
319 return 1;
320
321 return 0;
322}
323
324/* called under bridge lock */
325static void br_topology_change_acknowledged(struct net_bridge *br)
326{
327 br->topology_change_detected = 0;
328 del_timer(&br->tcn_timer);
329}
330
331/* called under bridge lock */
332void br_topology_change_detection(struct net_bridge *br)
333{
334 int isroot = br_is_root_bridge(br);
335
336 if (br->stp_enabled != BR_KERNEL_STP)
337 return;
338
339 br_info(br, "topology change detected, %s\n",
340 isroot ? "propagating" : "sending tcn bpdu");
341
342 if (isroot) {
343 __br_set_topology_change(br, 1);
344 mod_timer(&br->topology_change_timer, jiffies
345 + br->bridge_forward_delay + br->bridge_max_age);
346 } else if (!br->topology_change_detected) {
347 br_transmit_tcn(br);
348 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
349 }
350
351 br->topology_change_detected = 1;
352}
353
354/* called under bridge lock */
355void br_config_bpdu_generation(struct net_bridge *br)
356{
357 struct net_bridge_port *p;
358
359 list_for_each_entry(p, &br->port_list, list) {
360 if (p->state != BR_STATE_DISABLED &&
361 br_is_designated_port(p))
362 br_transmit_config(p);
363 }
364}
365
366/* called under bridge lock */
367static void br_reply(struct net_bridge_port *p)
368{
369 br_transmit_config(p);
370}
371
372/* called under bridge lock */
373void br_configuration_update(struct net_bridge *br)
374{
375 br_root_selection(br);
376 br_designated_port_selection(br);
377}
378
379/* called under bridge lock */
380void br_become_designated_port(struct net_bridge_port *p)
381{
382 struct net_bridge *br;
383
384 br = p->br;
385 p->designated_root = br->designated_root;
386 p->designated_cost = br->root_path_cost;
387 p->designated_bridge = br->bridge_id;
388 p->designated_port = p->port_id;
389}
390
391
392/* called under bridge lock */
393static void br_make_blocking(struct net_bridge_port *p)
394{
395 if (p->state != BR_STATE_DISABLED &&
396 p->state != BR_STATE_BLOCKING) {
397 if (p->state == BR_STATE_FORWARDING ||
398 p->state == BR_STATE_LEARNING)
399 br_topology_change_detection(p->br);
400
401 br_set_state(p, BR_STATE_BLOCKING);
402 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
403
404 del_timer(&p->forward_delay_timer);
405 }
406}
407
408/* called under bridge lock */
409static void br_make_forwarding(struct net_bridge_port *p)
410{
411 struct net_bridge *br = p->br;
412
413 if (p->state != BR_STATE_BLOCKING)
414 return;
415
416 if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
417 br_set_state(p, BR_STATE_FORWARDING);
418 br_topology_change_detection(br);
419 del_timer(&p->forward_delay_timer);
420 } else if (br->stp_enabled == BR_KERNEL_STP)
421 br_set_state(p, BR_STATE_LISTENING);
422 else
423 br_set_state(p, BR_STATE_LEARNING);
424
425 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
426
427 if (br->forward_delay != 0)
428 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
429}
430
431/* called under bridge lock */
432void br_port_state_selection(struct net_bridge *br)
433{
434 struct net_bridge_port *p;
435 unsigned int liveports = 0;
436
437 list_for_each_entry(p, &br->port_list, list) {
438 if (p->state == BR_STATE_DISABLED)
439 continue;
440
441 /* Don't change port states if userspace is handling STP */
442 if (br->stp_enabled != BR_USER_STP) {
443 if (p->port_no == br->root_port) {
444 p->config_pending = 0;
445 p->topology_change_ack = 0;
446 br_make_forwarding(p);
447 } else if (br_is_designated_port(p)) {
448 del_timer(&p->message_age_timer);
449 br_make_forwarding(p);
450 } else {
451 p->config_pending = 0;
452 p->topology_change_ack = 0;
453 br_make_blocking(p);
454 }
455 }
456
457 if (p->state != BR_STATE_BLOCKING)
458 br_multicast_enable_port(p);
459 /* Multicast is not disabled for the port when it goes in
460 * blocking state because the timers will expire and stop by
461 * themselves without sending more queries.
462 */
463 if (p->state == BR_STATE_FORWARDING)
464 ++liveports;
465 }
466
467 if (liveports == 0)
468 netif_carrier_off(br->dev);
469 else
470 netif_carrier_on(br->dev);
471}
472
473/* called under bridge lock */
474static void br_topology_change_acknowledge(struct net_bridge_port *p)
475{
476 p->topology_change_ack = 1;
477 br_transmit_config(p);
478}
479
480/* called under bridge lock */
481void br_received_config_bpdu(struct net_bridge_port *p,
482 const struct br_config_bpdu *bpdu)
483{
484 struct net_bridge *br;
485 int was_root;
486
487 br = p->br;
488 was_root = br_is_root_bridge(br);
489
490 if (br_supersedes_port_info(p, bpdu)) {
491 br_record_config_information(p, bpdu);
492 br_configuration_update(br);
493 br_port_state_selection(br);
494
495 if (!br_is_root_bridge(br) && was_root) {
496 del_timer(&br->hello_timer);
497 if (br->topology_change_detected) {
498 del_timer(&br->topology_change_timer);
499 br_transmit_tcn(br);
500
501 mod_timer(&br->tcn_timer,
502 jiffies + br->bridge_hello_time);
503 }
504 }
505
506 if (p->port_no == br->root_port) {
507 br_record_config_timeout_values(br, bpdu);
508 br_config_bpdu_generation(br);
509 if (bpdu->topology_change_ack)
510 br_topology_change_acknowledged(br);
511 }
512 } else if (br_is_designated_port(p)) {
513 br_reply(p);
514 }
515}
516
517/* called under bridge lock */
518void br_received_tcn_bpdu(struct net_bridge_port *p)
519{
520 if (br_is_designated_port(p)) {
521 br_info(p->br, "port %u(%s) received tcn bpdu\n",
522 (unsigned int) p->port_no, p->dev->name);
523
524 br_topology_change_detection(p->br);
525 br_topology_change_acknowledge(p);
526 }
527}
528
529/* Change bridge STP parameter */
530int br_set_hello_time(struct net_bridge *br, unsigned long val)
531{
532 unsigned long t = clock_t_to_jiffies(val);
533
534 if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
535 return -ERANGE;
536
537 spin_lock_bh(&br->lock);
538 br->bridge_hello_time = t;
539 if (br_is_root_bridge(br))
540 br->hello_time = br->bridge_hello_time;
541 spin_unlock_bh(&br->lock);
542 return 0;
543}
544
545int br_set_max_age(struct net_bridge *br, unsigned long val)
546{
547 unsigned long t = clock_t_to_jiffies(val);
548
549 if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
550 return -ERANGE;
551
552 spin_lock_bh(&br->lock);
553 br->bridge_max_age = t;
554 if (br_is_root_bridge(br))
555 br->max_age = br->bridge_max_age;
556 spin_unlock_bh(&br->lock);
557 return 0;
558
559}
560
561/* called under bridge lock */
562int __set_ageing_time(struct net_device *dev, unsigned long t)
563{
564 struct switchdev_attr attr = {
565 .orig_dev = dev,
566 .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
567 .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER,
568 .u.ageing_time = jiffies_to_clock_t(t),
569 };
570 int err;
571
572 err = switchdev_port_attr_set(dev, &attr);
573 if (err && err != -EOPNOTSUPP)
574 return err;
575
576 return 0;
577}
578
579/* Set time interval that dynamic forwarding entries live
580 * For pure software bridge, allow values outside the 802.1
581 * standard specification for special cases:
582 * 0 - entry never ages (all permanant)
583 * 1 - entry disappears (no persistance)
584 *
585 * Offloaded switch entries maybe more restrictive
586 */
587int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time)
588{
589 unsigned long t = clock_t_to_jiffies(ageing_time);
590 int err;
591
592 err = __set_ageing_time(br->dev, t);
593 if (err)
594 return err;
595
596 spin_lock_bh(&br->lock);
597 br->bridge_ageing_time = t;
598 br->ageing_time = t;
599 spin_unlock_bh(&br->lock);
600
601 mod_delayed_work(system_long_wq, &br->gc_work, 0);
602
603 return 0;
604}
605
606/* called under bridge lock */
607void __br_set_topology_change(struct net_bridge *br, unsigned char val)
608{
609 unsigned long t;
610 int err;
611
612 if (br->stp_enabled == BR_KERNEL_STP && br->topology_change != val) {
613 /* On topology change, set the bridge ageing time to twice the
614 * forward delay. Otherwise, restore its default ageing time.
615 */
616
617 if (val) {
618 t = 2 * br->forward_delay;
619 br_debug(br, "decreasing ageing time to %lu\n", t);
620 } else {
621 t = br->bridge_ageing_time;
622 br_debug(br, "restoring ageing time to %lu\n", t);
623 }
624
625 err = __set_ageing_time(br->dev, t);
626 if (err)
627 br_warn(br, "error offloading ageing time\n");
628 else
629 br->ageing_time = t;
630 }
631
632 br->topology_change = val;
633}
634
635void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
636{
637 br->bridge_forward_delay = t;
638 if (br_is_root_bridge(br))
639 br->forward_delay = br->bridge_forward_delay;
640}
641
642int br_set_forward_delay(struct net_bridge *br, unsigned long val)
643{
644 unsigned long t = clock_t_to_jiffies(val);
645 int err = -ERANGE;
646
647 spin_lock_bh(&br->lock);
648 if (br->stp_enabled != BR_NO_STP &&
649 (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
650 goto unlock;
651
652 __br_set_forward_delay(br, t);
653 err = 0;
654
655unlock:
656 spin_unlock_bh(&br->lock);
657 return err;
658}
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}