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 /* Don't change the state of the ports if they are driven by a different
40 * protocol.
41 */
42 if (p->flags & BR_MRP_AWARE)
43 return;
44
45 p->state = state;
46 if (br_opt_get(p->br, BROPT_MST_ENABLED)) {
47 err = br_mst_set_state(p, 0, state, NULL);
48 if (err)
49 br_warn(p->br, "error setting MST state on port %u(%s)\n",
50 p->port_no, netdev_name(p->dev));
51 }
52 err = switchdev_port_attr_set(p->dev, &attr, NULL);
53 if (err && err != -EOPNOTSUPP)
54 br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
55 (unsigned int) p->port_no, p->dev->name);
56 else
57 br_info(p->br, "port %u(%s) entered %s state\n",
58 (unsigned int) p->port_no, p->dev->name,
59 br_port_state_names[p->state]);
60
61 if (p->br->stp_enabled == BR_KERNEL_STP) {
62 switch (p->state) {
63 case BR_STATE_BLOCKING:
64 p->stp_xstats.transition_blk++;
65 break;
66 case BR_STATE_FORWARDING:
67 p->stp_xstats.transition_fwd++;
68 break;
69 }
70 }
71}
72
73u8 br_port_get_stp_state(const struct net_device *dev)
74{
75 struct net_bridge_port *p;
76
77 ASSERT_RTNL();
78
79 p = br_port_get_rtnl(dev);
80 if (!p)
81 return BR_STATE_DISABLED;
82
83 return p->state;
84}
85EXPORT_SYMBOL_GPL(br_port_get_stp_state);
86
87/* called under bridge lock */
88struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
89{
90 struct net_bridge_port *p;
91
92 list_for_each_entry_rcu(p, &br->port_list, list,
93 lockdep_is_held(&br->lock)) {
94 if (p->port_no == port_no)
95 return p;
96 }
97
98 return NULL;
99}
100
101/* called under bridge lock */
102static int br_should_become_root_port(const struct net_bridge_port *p,
103 u16 root_port)
104{
105 struct net_bridge *br;
106 struct net_bridge_port *rp;
107 int t;
108
109 br = p->br;
110 if (p->state == BR_STATE_DISABLED ||
111 br_is_designated_port(p))
112 return 0;
113
114 if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
115 return 0;
116
117 if (!root_port)
118 return 1;
119
120 rp = br_get_port(br, root_port);
121
122 t = memcmp(&p->designated_root, &rp->designated_root, 8);
123 if (t < 0)
124 return 1;
125 else if (t > 0)
126 return 0;
127
128 if (p->designated_cost + p->path_cost <
129 rp->designated_cost + rp->path_cost)
130 return 1;
131 else if (p->designated_cost + p->path_cost >
132 rp->designated_cost + rp->path_cost)
133 return 0;
134
135 t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
136 if (t < 0)
137 return 1;
138 else if (t > 0)
139 return 0;
140
141 if (p->designated_port < rp->designated_port)
142 return 1;
143 else if (p->designated_port > rp->designated_port)
144 return 0;
145
146 if (p->port_id < rp->port_id)
147 return 1;
148
149 return 0;
150}
151
152static void br_root_port_block(const struct net_bridge *br,
153 struct net_bridge_port *p)
154{
155
156 br_notice(br, "port %u(%s) tried to become root port (blocked)",
157 (unsigned int) p->port_no, p->dev->name);
158
159 br_set_state(p, BR_STATE_LISTENING);
160 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
161
162 if (br->forward_delay > 0)
163 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
164}
165
166/* called under bridge lock */
167static void br_root_selection(struct net_bridge *br)
168{
169 struct net_bridge_port *p;
170 u16 root_port = 0;
171
172 list_for_each_entry(p, &br->port_list, list) {
173 if (!br_should_become_root_port(p, root_port))
174 continue;
175
176 if (p->flags & BR_ROOT_BLOCK)
177 br_root_port_block(br, p);
178 else
179 root_port = p->port_no;
180 }
181
182 br->root_port = root_port;
183
184 if (!root_port) {
185 br->designated_root = br->bridge_id;
186 br->root_path_cost = 0;
187 } else {
188 p = br_get_port(br, root_port);
189 br->designated_root = p->designated_root;
190 br->root_path_cost = p->designated_cost + p->path_cost;
191 }
192}
193
194/* called under bridge lock */
195void br_become_root_bridge(struct net_bridge *br)
196{
197 br->max_age = br->bridge_max_age;
198 br->hello_time = br->bridge_hello_time;
199 br->forward_delay = br->bridge_forward_delay;
200 br_topology_change_detection(br);
201 del_timer(&br->tcn_timer);
202
203 if (br->dev->flags & IFF_UP) {
204 br_config_bpdu_generation(br);
205 mod_timer(&br->hello_timer, jiffies + br->hello_time);
206 }
207}
208
209/* called under bridge lock */
210void br_transmit_config(struct net_bridge_port *p)
211{
212 struct br_config_bpdu bpdu;
213 struct net_bridge *br;
214
215 if (timer_pending(&p->hold_timer)) {
216 p->config_pending = 1;
217 return;
218 }
219
220 br = p->br;
221
222 bpdu.topology_change = br->topology_change;
223 bpdu.topology_change_ack = p->topology_change_ack;
224 bpdu.root = br->designated_root;
225 bpdu.root_path_cost = br->root_path_cost;
226 bpdu.bridge_id = br->bridge_id;
227 bpdu.port_id = p->port_id;
228 if (br_is_root_bridge(br))
229 bpdu.message_age = 0;
230 else {
231 struct net_bridge_port *root
232 = br_get_port(br, br->root_port);
233 bpdu.message_age = (jiffies - root->designated_age)
234 + MESSAGE_AGE_INCR;
235 }
236 bpdu.max_age = br->max_age;
237 bpdu.hello_time = br->hello_time;
238 bpdu.forward_delay = br->forward_delay;
239
240 if (bpdu.message_age < br->max_age) {
241 br_send_config_bpdu(p, &bpdu);
242 p->topology_change_ack = 0;
243 p->config_pending = 0;
244 if (p->br->stp_enabled == BR_KERNEL_STP)
245 mod_timer(&p->hold_timer,
246 round_jiffies(jiffies + BR_HOLD_TIME));
247 }
248}
249
250/* called under bridge lock */
251static void br_record_config_information(struct net_bridge_port *p,
252 const struct br_config_bpdu *bpdu)
253{
254 p->designated_root = bpdu->root;
255 p->designated_cost = bpdu->root_path_cost;
256 p->designated_bridge = bpdu->bridge_id;
257 p->designated_port = bpdu->port_id;
258 p->designated_age = jiffies - bpdu->message_age;
259
260 mod_timer(&p->message_age_timer, jiffies
261 + (bpdu->max_age - bpdu->message_age));
262}
263
264/* called under bridge lock */
265static void br_record_config_timeout_values(struct net_bridge *br,
266 const struct br_config_bpdu *bpdu)
267{
268 br->max_age = bpdu->max_age;
269 br->hello_time = bpdu->hello_time;
270 br->forward_delay = bpdu->forward_delay;
271 __br_set_topology_change(br, bpdu->topology_change);
272}
273
274/* called under bridge lock */
275void br_transmit_tcn(struct net_bridge *br)
276{
277 struct net_bridge_port *p;
278
279 p = br_get_port(br, br->root_port);
280 if (p)
281 br_send_tcn_bpdu(p);
282 else
283 br_notice(br, "root port %u not found for topology notice\n",
284 br->root_port);
285}
286
287/* called under bridge lock */
288static int br_should_become_designated_port(const struct net_bridge_port *p)
289{
290 struct net_bridge *br;
291 int t;
292
293 br = p->br;
294 if (br_is_designated_port(p))
295 return 1;
296
297 if (memcmp(&p->designated_root, &br->designated_root, 8))
298 return 1;
299
300 if (br->root_path_cost < p->designated_cost)
301 return 1;
302 else if (br->root_path_cost > p->designated_cost)
303 return 0;
304
305 t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
306 if (t < 0)
307 return 1;
308 else if (t > 0)
309 return 0;
310
311 if (p->port_id < p->designated_port)
312 return 1;
313
314 return 0;
315}
316
317/* called under bridge lock */
318static void br_designated_port_selection(struct net_bridge *br)
319{
320 struct net_bridge_port *p;
321
322 list_for_each_entry(p, &br->port_list, list) {
323 if (p->state != BR_STATE_DISABLED &&
324 br_should_become_designated_port(p))
325 br_become_designated_port(p);
326
327 }
328}
329
330/* called under bridge lock */
331static int br_supersedes_port_info(const struct net_bridge_port *p,
332 const struct br_config_bpdu *bpdu)
333{
334 int t;
335
336 t = memcmp(&bpdu->root, &p->designated_root, 8);
337 if (t < 0)
338 return 1;
339 else if (t > 0)
340 return 0;
341
342 if (bpdu->root_path_cost < p->designated_cost)
343 return 1;
344 else if (bpdu->root_path_cost > p->designated_cost)
345 return 0;
346
347 t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
348 if (t < 0)
349 return 1;
350 else if (t > 0)
351 return 0;
352
353 if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
354 return 1;
355
356 if (bpdu->port_id <= p->designated_port)
357 return 1;
358
359 return 0;
360}
361
362/* called under bridge lock */
363static void br_topology_change_acknowledged(struct net_bridge *br)
364{
365 br->topology_change_detected = 0;
366 del_timer(&br->tcn_timer);
367}
368
369/* called under bridge lock */
370void br_topology_change_detection(struct net_bridge *br)
371{
372 int isroot = br_is_root_bridge(br);
373
374 if (br->stp_enabled != BR_KERNEL_STP)
375 return;
376
377 br_info(br, "topology change detected, %s\n",
378 isroot ? "propagating" : "sending tcn bpdu");
379
380 if (isroot) {
381 __br_set_topology_change(br, 1);
382 mod_timer(&br->topology_change_timer, jiffies
383 + br->bridge_forward_delay + br->bridge_max_age);
384 } else if (!br->topology_change_detected) {
385 br_transmit_tcn(br);
386 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
387 }
388
389 br->topology_change_detected = 1;
390}
391
392/* called under bridge lock */
393void br_config_bpdu_generation(struct net_bridge *br)
394{
395 struct net_bridge_port *p;
396
397 list_for_each_entry(p, &br->port_list, list) {
398 if (p->state != BR_STATE_DISABLED &&
399 br_is_designated_port(p))
400 br_transmit_config(p);
401 }
402}
403
404/* called under bridge lock */
405static void br_reply(struct net_bridge_port *p)
406{
407 br_transmit_config(p);
408}
409
410/* called under bridge lock */
411void br_configuration_update(struct net_bridge *br)
412{
413 br_root_selection(br);
414 br_designated_port_selection(br);
415}
416
417/* called under bridge lock */
418void br_become_designated_port(struct net_bridge_port *p)
419{
420 struct net_bridge *br;
421
422 br = p->br;
423 p->designated_root = br->designated_root;
424 p->designated_cost = br->root_path_cost;
425 p->designated_bridge = br->bridge_id;
426 p->designated_port = p->port_id;
427}
428
429
430/* called under bridge lock */
431static void br_make_blocking(struct net_bridge_port *p)
432{
433 if (p->state != BR_STATE_DISABLED &&
434 p->state != BR_STATE_BLOCKING) {
435 if (p->state == BR_STATE_FORWARDING ||
436 p->state == BR_STATE_LEARNING)
437 br_topology_change_detection(p->br);
438
439 br_set_state(p, BR_STATE_BLOCKING);
440 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
441
442 del_timer(&p->forward_delay_timer);
443 }
444}
445
446/* called under bridge lock */
447static void br_make_forwarding(struct net_bridge_port *p)
448{
449 struct net_bridge *br = p->br;
450
451 if (p->state != BR_STATE_BLOCKING)
452 return;
453
454 if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
455 br_set_state(p, BR_STATE_FORWARDING);
456 br_topology_change_detection(br);
457 del_timer(&p->forward_delay_timer);
458 } else if (br->stp_enabled == BR_KERNEL_STP)
459 br_set_state(p, BR_STATE_LISTENING);
460 else
461 br_set_state(p, BR_STATE_LEARNING);
462
463 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
464
465 if (br->forward_delay != 0)
466 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
467}
468
469/* called under bridge lock */
470void br_port_state_selection(struct net_bridge *br)
471{
472 struct net_bridge_port *p;
473 unsigned int liveports = 0;
474
475 list_for_each_entry(p, &br->port_list, list) {
476 if (p->state == BR_STATE_DISABLED)
477 continue;
478
479 /* Don't change port states if userspace is handling STP */
480 if (br->stp_enabled != BR_USER_STP) {
481 if (p->port_no == br->root_port) {
482 p->config_pending = 0;
483 p->topology_change_ack = 0;
484 br_make_forwarding(p);
485 } else if (br_is_designated_port(p)) {
486 del_timer(&p->message_age_timer);
487 br_make_forwarding(p);
488 } else {
489 p->config_pending = 0;
490 p->topology_change_ack = 0;
491 br_make_blocking(p);
492 }
493 }
494
495 if (p->state != BR_STATE_BLOCKING)
496 br_multicast_enable_port(p);
497 /* Multicast is not disabled for the port when it goes in
498 * blocking state because the timers will expire and stop by
499 * themselves without sending more queries.
500 */
501 if (p->state == BR_STATE_FORWARDING)
502 ++liveports;
503 }
504
505 if (liveports == 0)
506 netif_carrier_off(br->dev);
507 else
508 netif_carrier_on(br->dev);
509}
510
511/* called under bridge lock */
512static void br_topology_change_acknowledge(struct net_bridge_port *p)
513{
514 p->topology_change_ack = 1;
515 br_transmit_config(p);
516}
517
518/* called under bridge lock */
519void br_received_config_bpdu(struct net_bridge_port *p,
520 const struct br_config_bpdu *bpdu)
521{
522 struct net_bridge *br;
523 int was_root;
524
525 p->stp_xstats.rx_bpdu++;
526
527 br = p->br;
528 was_root = br_is_root_bridge(br);
529
530 if (br_supersedes_port_info(p, bpdu)) {
531 br_record_config_information(p, bpdu);
532 br_configuration_update(br);
533 br_port_state_selection(br);
534
535 if (!br_is_root_bridge(br) && was_root) {
536 del_timer(&br->hello_timer);
537 if (br->topology_change_detected) {
538 del_timer(&br->topology_change_timer);
539 br_transmit_tcn(br);
540
541 mod_timer(&br->tcn_timer,
542 jiffies + br->bridge_hello_time);
543 }
544 }
545
546 if (p->port_no == br->root_port) {
547 br_record_config_timeout_values(br, bpdu);
548 br_config_bpdu_generation(br);
549 if (bpdu->topology_change_ack)
550 br_topology_change_acknowledged(br);
551 }
552 } else if (br_is_designated_port(p)) {
553 br_reply(p);
554 }
555}
556
557/* called under bridge lock */
558void br_received_tcn_bpdu(struct net_bridge_port *p)
559{
560 p->stp_xstats.rx_tcn++;
561
562 if (br_is_designated_port(p)) {
563 br_info(p->br, "port %u(%s) received tcn bpdu\n",
564 (unsigned int) p->port_no, p->dev->name);
565
566 br_topology_change_detection(p->br);
567 br_topology_change_acknowledge(p);
568 }
569}
570
571/* Change bridge STP parameter */
572int br_set_hello_time(struct net_bridge *br, unsigned long val)
573{
574 unsigned long t = clock_t_to_jiffies(val);
575
576 if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
577 return -ERANGE;
578
579 spin_lock_bh(&br->lock);
580 br->bridge_hello_time = t;
581 if (br_is_root_bridge(br))
582 br->hello_time = br->bridge_hello_time;
583 spin_unlock_bh(&br->lock);
584 return 0;
585}
586
587int br_set_max_age(struct net_bridge *br, unsigned long val)
588{
589 unsigned long t = clock_t_to_jiffies(val);
590
591 if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
592 return -ERANGE;
593
594 spin_lock_bh(&br->lock);
595 br->bridge_max_age = t;
596 if (br_is_root_bridge(br))
597 br->max_age = br->bridge_max_age;
598 spin_unlock_bh(&br->lock);
599 return 0;
600
601}
602
603/* called under bridge lock */
604int __set_ageing_time(struct net_device *dev, unsigned long t)
605{
606 struct switchdev_attr attr = {
607 .orig_dev = dev,
608 .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
609 .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER,
610 .u.ageing_time = jiffies_to_clock_t(t),
611 };
612 int err;
613
614 err = switchdev_port_attr_set(dev, &attr, NULL);
615 if (err && err != -EOPNOTSUPP)
616 return err;
617
618 return 0;
619}
620
621/* Set time interval that dynamic forwarding entries live
622 * For pure software bridge, allow values outside the 802.1
623 * standard specification for special cases:
624 * 0 - entry never ages (all permanent)
625 * 1 - entry disappears (no persistence)
626 *
627 * Offloaded switch entries maybe more restrictive
628 */
629int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time)
630{
631 unsigned long t = clock_t_to_jiffies(ageing_time);
632 int err;
633
634 err = __set_ageing_time(br->dev, t);
635 if (err)
636 return err;
637
638 spin_lock_bh(&br->lock);
639 br->bridge_ageing_time = t;
640 br->ageing_time = t;
641 spin_unlock_bh(&br->lock);
642
643 mod_delayed_work(system_long_wq, &br->gc_work, 0);
644
645 return 0;
646}
647
648clock_t br_get_ageing_time(const struct net_device *br_dev)
649{
650 const struct net_bridge *br;
651
652 if (!netif_is_bridge_master(br_dev))
653 return 0;
654
655 br = netdev_priv(br_dev);
656
657 return jiffies_to_clock_t(br->ageing_time);
658}
659EXPORT_SYMBOL_GPL(br_get_ageing_time);
660
661/* called under bridge lock */
662void __br_set_topology_change(struct net_bridge *br, unsigned char val)
663{
664 unsigned long t;
665 int err;
666
667 if (br->stp_enabled == BR_KERNEL_STP && br->topology_change != val) {
668 /* On topology change, set the bridge ageing time to twice the
669 * forward delay. Otherwise, restore its default ageing time.
670 */
671
672 if (val) {
673 t = 2 * br->forward_delay;
674 br_debug(br, "decreasing ageing time to %lu\n", t);
675 } else {
676 t = br->bridge_ageing_time;
677 br_debug(br, "restoring ageing time to %lu\n", t);
678 }
679
680 err = __set_ageing_time(br->dev, t);
681 if (err)
682 br_warn(br, "error offloading ageing time\n");
683 else
684 br->ageing_time = t;
685 }
686
687 br->topology_change = val;
688}
689
690void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
691{
692 br->bridge_forward_delay = t;
693 if (br_is_root_bridge(br))
694 br->forward_delay = br->bridge_forward_delay;
695}
696
697int br_set_forward_delay(struct net_bridge *br, unsigned long val)
698{
699 unsigned long t = clock_t_to_jiffies(val);
700 int err = -ERANGE;
701
702 spin_lock_bh(&br->lock);
703 if (br->stp_enabled != BR_NO_STP &&
704 (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
705 goto unlock;
706
707 __br_set_forward_delay(br, t);
708 err = 0;
709
710unlock:
711 spin_unlock_bh(&br->lock);
712 return err;
713}
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}