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