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1/*
2 * Spanning tree protocol; generic parts
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 */
13#include <linux/kernel.h>
14#include <linux/rculist.h>
15#include <net/switchdev.h>
16
17#include "br_private.h"
18#include "br_private_stp.h"
19
20/* since time values in bpdu are in jiffies and then scaled (1/256)
21 * before sending, make sure that is at least one STP tick.
22 */
23#define MESSAGE_AGE_INCR ((HZ / 256) + 1)
24
25static const char *const br_port_state_names[] = {
26 [BR_STATE_DISABLED] = "disabled",
27 [BR_STATE_LISTENING] = "listening",
28 [BR_STATE_LEARNING] = "learning",
29 [BR_STATE_FORWARDING] = "forwarding",
30 [BR_STATE_BLOCKING] = "blocking",
31};
32
33void br_set_state(struct net_bridge_port *p, unsigned int state)
34{
35 struct switchdev_attr attr = {
36 .orig_dev = p->dev,
37 .id = SWITCHDEV_ATTR_ID_PORT_STP_STATE,
38 .flags = SWITCHDEV_F_DEFER,
39 .u.stp_state = state,
40 };
41 int err;
42
43 p->state = state;
44 err = switchdev_port_attr_set(p->dev, &attr);
45 if (err && err != -EOPNOTSUPP)
46 br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
47 (unsigned int) p->port_no, p->dev->name);
48 else
49 br_info(p->br, "port %u(%s) entered %s state\n",
50 (unsigned int) p->port_no, p->dev->name,
51 br_port_state_names[p->state]);
52}
53
54/* called under bridge lock */
55struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
56{
57 struct net_bridge_port *p;
58
59 list_for_each_entry_rcu(p, &br->port_list, list) {
60 if (p->port_no == port_no)
61 return p;
62 }
63
64 return NULL;
65}
66
67/* called under bridge lock */
68static int br_should_become_root_port(const struct net_bridge_port *p,
69 u16 root_port)
70{
71 struct net_bridge *br;
72 struct net_bridge_port *rp;
73 int t;
74
75 br = p->br;
76 if (p->state == BR_STATE_DISABLED ||
77 br_is_designated_port(p))
78 return 0;
79
80 if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
81 return 0;
82
83 if (!root_port)
84 return 1;
85
86 rp = br_get_port(br, root_port);
87
88 t = memcmp(&p->designated_root, &rp->designated_root, 8);
89 if (t < 0)
90 return 1;
91 else if (t > 0)
92 return 0;
93
94 if (p->designated_cost + p->path_cost <
95 rp->designated_cost + rp->path_cost)
96 return 1;
97 else if (p->designated_cost + p->path_cost >
98 rp->designated_cost + rp->path_cost)
99 return 0;
100
101 t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
102 if (t < 0)
103 return 1;
104 else if (t > 0)
105 return 0;
106
107 if (p->designated_port < rp->designated_port)
108 return 1;
109 else if (p->designated_port > rp->designated_port)
110 return 0;
111
112 if (p->port_id < rp->port_id)
113 return 1;
114
115 return 0;
116}
117
118static void br_root_port_block(const struct net_bridge *br,
119 struct net_bridge_port *p)
120{
121
122 br_notice(br, "port %u(%s) tried to become root port (blocked)",
123 (unsigned int) p->port_no, p->dev->name);
124
125 br_set_state(p, BR_STATE_LISTENING);
126 br_ifinfo_notify(RTM_NEWLINK, p);
127
128 if (br->forward_delay > 0)
129 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
130}
131
132/* called under bridge lock */
133static void br_root_selection(struct net_bridge *br)
134{
135 struct net_bridge_port *p;
136 u16 root_port = 0;
137
138 list_for_each_entry(p, &br->port_list, list) {
139 if (!br_should_become_root_port(p, root_port))
140 continue;
141
142 if (p->flags & BR_ROOT_BLOCK)
143 br_root_port_block(br, p);
144 else
145 root_port = p->port_no;
146 }
147
148 br->root_port = root_port;
149
150 if (!root_port) {
151 br->designated_root = br->bridge_id;
152 br->root_path_cost = 0;
153 } else {
154 p = br_get_port(br, root_port);
155 br->designated_root = p->designated_root;
156 br->root_path_cost = p->designated_cost + p->path_cost;
157 }
158}
159
160/* called under bridge lock */
161void br_become_root_bridge(struct net_bridge *br)
162{
163 br->max_age = br->bridge_max_age;
164 br->hello_time = br->bridge_hello_time;
165 br->forward_delay = br->bridge_forward_delay;
166 br_topology_change_detection(br);
167 del_timer(&br->tcn_timer);
168
169 if (br->dev->flags & IFF_UP) {
170 br_config_bpdu_generation(br);
171 mod_timer(&br->hello_timer, jiffies + br->hello_time);
172 }
173}
174
175/* called under bridge lock */
176void br_transmit_config(struct net_bridge_port *p)
177{
178 struct br_config_bpdu bpdu;
179 struct net_bridge *br;
180
181 if (timer_pending(&p->hold_timer)) {
182 p->config_pending = 1;
183 return;
184 }
185
186 br = p->br;
187
188 bpdu.topology_change = br->topology_change;
189 bpdu.topology_change_ack = p->topology_change_ack;
190 bpdu.root = br->designated_root;
191 bpdu.root_path_cost = br->root_path_cost;
192 bpdu.bridge_id = br->bridge_id;
193 bpdu.port_id = p->port_id;
194 if (br_is_root_bridge(br))
195 bpdu.message_age = 0;
196 else {
197 struct net_bridge_port *root
198 = br_get_port(br, br->root_port);
199 bpdu.message_age = (jiffies - root->designated_age)
200 + MESSAGE_AGE_INCR;
201 }
202 bpdu.max_age = br->max_age;
203 bpdu.hello_time = br->hello_time;
204 bpdu.forward_delay = br->forward_delay;
205
206 if (bpdu.message_age < br->max_age) {
207 br_send_config_bpdu(p, &bpdu);
208 p->topology_change_ack = 0;
209 p->config_pending = 0;
210 if (p->br->stp_enabled == BR_KERNEL_STP)
211 mod_timer(&p->hold_timer,
212 round_jiffies(jiffies + BR_HOLD_TIME));
213 }
214}
215
216/* called under bridge lock */
217static void br_record_config_information(struct net_bridge_port *p,
218 const struct br_config_bpdu *bpdu)
219{
220 p->designated_root = bpdu->root;
221 p->designated_cost = bpdu->root_path_cost;
222 p->designated_bridge = bpdu->bridge_id;
223 p->designated_port = bpdu->port_id;
224 p->designated_age = jiffies - bpdu->message_age;
225
226 mod_timer(&p->message_age_timer, jiffies
227 + (bpdu->max_age - bpdu->message_age));
228}
229
230/* called under bridge lock */
231static void br_record_config_timeout_values(struct net_bridge *br,
232 const struct br_config_bpdu *bpdu)
233{
234 br->max_age = bpdu->max_age;
235 br->hello_time = bpdu->hello_time;
236 br->forward_delay = bpdu->forward_delay;
237 br->topology_change = bpdu->topology_change;
238}
239
240/* called under bridge lock */
241void br_transmit_tcn(struct net_bridge *br)
242{
243 struct net_bridge_port *p;
244
245 p = br_get_port(br, br->root_port);
246 if (p)
247 br_send_tcn_bpdu(p);
248 else
249 br_notice(br, "root port %u not found for topology notice\n",
250 br->root_port);
251}
252
253/* called under bridge lock */
254static int br_should_become_designated_port(const struct net_bridge_port *p)
255{
256 struct net_bridge *br;
257 int t;
258
259 br = p->br;
260 if (br_is_designated_port(p))
261 return 1;
262
263 if (memcmp(&p->designated_root, &br->designated_root, 8))
264 return 1;
265
266 if (br->root_path_cost < p->designated_cost)
267 return 1;
268 else if (br->root_path_cost > p->designated_cost)
269 return 0;
270
271 t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
272 if (t < 0)
273 return 1;
274 else if (t > 0)
275 return 0;
276
277 if (p->port_id < p->designated_port)
278 return 1;
279
280 return 0;
281}
282
283/* called under bridge lock */
284static void br_designated_port_selection(struct net_bridge *br)
285{
286 struct net_bridge_port *p;
287
288 list_for_each_entry(p, &br->port_list, list) {
289 if (p->state != BR_STATE_DISABLED &&
290 br_should_become_designated_port(p))
291 br_become_designated_port(p);
292
293 }
294}
295
296/* called under bridge lock */
297static int br_supersedes_port_info(const struct net_bridge_port *p,
298 const struct br_config_bpdu *bpdu)
299{
300 int t;
301
302 t = memcmp(&bpdu->root, &p->designated_root, 8);
303 if (t < 0)
304 return 1;
305 else if (t > 0)
306 return 0;
307
308 if (bpdu->root_path_cost < p->designated_cost)
309 return 1;
310 else if (bpdu->root_path_cost > p->designated_cost)
311 return 0;
312
313 t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
314 if (t < 0)
315 return 1;
316 else if (t > 0)
317 return 0;
318
319 if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
320 return 1;
321
322 if (bpdu->port_id <= p->designated_port)
323 return 1;
324
325 return 0;
326}
327
328/* called under bridge lock */
329static void br_topology_change_acknowledged(struct net_bridge *br)
330{
331 br->topology_change_detected = 0;
332 del_timer(&br->tcn_timer);
333}
334
335/* called under bridge lock */
336void br_topology_change_detection(struct net_bridge *br)
337{
338 int isroot = br_is_root_bridge(br);
339
340 if (br->stp_enabled != BR_KERNEL_STP)
341 return;
342
343 br_info(br, "topology change detected, %s\n",
344 isroot ? "propagating" : "sending tcn bpdu");
345
346 if (isroot) {
347 br->topology_change = 1;
348 mod_timer(&br->topology_change_timer, jiffies
349 + br->bridge_forward_delay + br->bridge_max_age);
350 } else if (!br->topology_change_detected) {
351 br_transmit_tcn(br);
352 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
353 }
354
355 br->topology_change_detected = 1;
356}
357
358/* called under bridge lock */
359void br_config_bpdu_generation(struct net_bridge *br)
360{
361 struct net_bridge_port *p;
362
363 list_for_each_entry(p, &br->port_list, list) {
364 if (p->state != BR_STATE_DISABLED &&
365 br_is_designated_port(p))
366 br_transmit_config(p);
367 }
368}
369
370/* called under bridge lock */
371static void br_reply(struct net_bridge_port *p)
372{
373 br_transmit_config(p);
374}
375
376/* called under bridge lock */
377void br_configuration_update(struct net_bridge *br)
378{
379 br_root_selection(br);
380 br_designated_port_selection(br);
381}
382
383/* called under bridge lock */
384void br_become_designated_port(struct net_bridge_port *p)
385{
386 struct net_bridge *br;
387
388 br = p->br;
389 p->designated_root = br->designated_root;
390 p->designated_cost = br->root_path_cost;
391 p->designated_bridge = br->bridge_id;
392 p->designated_port = p->port_id;
393}
394
395
396/* called under bridge lock */
397static void br_make_blocking(struct net_bridge_port *p)
398{
399 if (p->state != BR_STATE_DISABLED &&
400 p->state != BR_STATE_BLOCKING) {
401 if (p->state == BR_STATE_FORWARDING ||
402 p->state == BR_STATE_LEARNING)
403 br_topology_change_detection(p->br);
404
405 br_set_state(p, BR_STATE_BLOCKING);
406 br_ifinfo_notify(RTM_NEWLINK, p);
407
408 del_timer(&p->forward_delay_timer);
409 }
410}
411
412/* called under bridge lock */
413static void br_make_forwarding(struct net_bridge_port *p)
414{
415 struct net_bridge *br = p->br;
416
417 if (p->state != BR_STATE_BLOCKING)
418 return;
419
420 if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
421 br_set_state(p, BR_STATE_FORWARDING);
422 br_topology_change_detection(br);
423 del_timer(&p->forward_delay_timer);
424 } else if (br->stp_enabled == BR_KERNEL_STP)
425 br_set_state(p, BR_STATE_LISTENING);
426 else
427 br_set_state(p, BR_STATE_LEARNING);
428
429 br_ifinfo_notify(RTM_NEWLINK, p);
430
431 if (br->forward_delay != 0)
432 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
433}
434
435/* called under bridge lock */
436void br_port_state_selection(struct net_bridge *br)
437{
438 struct net_bridge_port *p;
439 unsigned int liveports = 0;
440
441 list_for_each_entry(p, &br->port_list, list) {
442 if (p->state == BR_STATE_DISABLED)
443 continue;
444
445 /* Don't change port states if userspace is handling STP */
446 if (br->stp_enabled != BR_USER_STP) {
447 if (p->port_no == br->root_port) {
448 p->config_pending = 0;
449 p->topology_change_ack = 0;
450 br_make_forwarding(p);
451 } else if (br_is_designated_port(p)) {
452 del_timer(&p->message_age_timer);
453 br_make_forwarding(p);
454 } else {
455 p->config_pending = 0;
456 p->topology_change_ack = 0;
457 br_make_blocking(p);
458 }
459 }
460
461 if (p->state != BR_STATE_BLOCKING)
462 br_multicast_enable_port(p);
463 /* Multicast is not disabled for the port when it goes in
464 * blocking state because the timers will expire and stop by
465 * themselves without sending more queries.
466 */
467 if (p->state == BR_STATE_FORWARDING)
468 ++liveports;
469 }
470
471 if (liveports == 0)
472 netif_carrier_off(br->dev);
473 else
474 netif_carrier_on(br->dev);
475}
476
477/* called under bridge lock */
478static void br_topology_change_acknowledge(struct net_bridge_port *p)
479{
480 p->topology_change_ack = 1;
481 br_transmit_config(p);
482}
483
484/* called under bridge lock */
485void br_received_config_bpdu(struct net_bridge_port *p,
486 const struct br_config_bpdu *bpdu)
487{
488 struct net_bridge *br;
489 int was_root;
490
491 br = p->br;
492 was_root = br_is_root_bridge(br);
493
494 if (br_supersedes_port_info(p, bpdu)) {
495 br_record_config_information(p, bpdu);
496 br_configuration_update(br);
497 br_port_state_selection(br);
498
499 if (!br_is_root_bridge(br) && was_root) {
500 del_timer(&br->hello_timer);
501 if (br->topology_change_detected) {
502 del_timer(&br->topology_change_timer);
503 br_transmit_tcn(br);
504
505 mod_timer(&br->tcn_timer,
506 jiffies + br->bridge_hello_time);
507 }
508 }
509
510 if (p->port_no == br->root_port) {
511 br_record_config_timeout_values(br, bpdu);
512 br_config_bpdu_generation(br);
513 if (bpdu->topology_change_ack)
514 br_topology_change_acknowledged(br);
515 }
516 } else if (br_is_designated_port(p)) {
517 br_reply(p);
518 }
519}
520
521/* called under bridge lock */
522void br_received_tcn_bpdu(struct net_bridge_port *p)
523{
524 if (br_is_designated_port(p)) {
525 br_info(p->br, "port %u(%s) received tcn bpdu\n",
526 (unsigned int) p->port_no, p->dev->name);
527
528 br_topology_change_detection(p->br);
529 br_topology_change_acknowledge(p);
530 }
531}
532
533/* Change bridge STP parameter */
534int br_set_hello_time(struct net_bridge *br, unsigned long val)
535{
536 unsigned long t = clock_t_to_jiffies(val);
537
538 if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
539 return -ERANGE;
540
541 spin_lock_bh(&br->lock);
542 br->bridge_hello_time = t;
543 if (br_is_root_bridge(br))
544 br->hello_time = br->bridge_hello_time;
545 spin_unlock_bh(&br->lock);
546 return 0;
547}
548
549int br_set_max_age(struct net_bridge *br, unsigned long val)
550{
551 unsigned long t = clock_t_to_jiffies(val);
552
553 if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
554 return -ERANGE;
555
556 spin_lock_bh(&br->lock);
557 br->bridge_max_age = t;
558 if (br_is_root_bridge(br))
559 br->max_age = br->bridge_max_age;
560 spin_unlock_bh(&br->lock);
561 return 0;
562
563}
564
565/* Set time interval that dynamic forwarding entries live
566 * For pure software bridge, allow values outside the 802.1
567 * standard specification for special cases:
568 * 0 - entry never ages (all permanant)
569 * 1 - entry disappears (no persistance)
570 *
571 * Offloaded switch entries maybe more restrictive
572 */
573int br_set_ageing_time(struct net_bridge *br, u32 ageing_time)
574{
575 struct switchdev_attr attr = {
576 .orig_dev = br->dev,
577 .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
578 .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP,
579 .u.ageing_time = ageing_time,
580 };
581 unsigned long t = clock_t_to_jiffies(ageing_time);
582 int err;
583
584 err = switchdev_port_attr_set(br->dev, &attr);
585 if (err && err != -EOPNOTSUPP)
586 return err;
587
588 br->ageing_time = t;
589 mod_timer(&br->gc_timer, jiffies);
590
591 return 0;
592}
593
594void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
595{
596 br->bridge_forward_delay = t;
597 if (br_is_root_bridge(br))
598 br->forward_delay = br->bridge_forward_delay;
599}
600
601int br_set_forward_delay(struct net_bridge *br, unsigned long val)
602{
603 unsigned long t = clock_t_to_jiffies(val);
604 int err = -ERANGE;
605
606 spin_lock_bh(&br->lock);
607 if (br->stp_enabled != BR_NO_STP &&
608 (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
609 goto unlock;
610
611 __br_set_forward_delay(br, t);
612 err = 0;
613
614unlock:
615 spin_unlock_bh(&br->lock);
616 return err;
617}
1// 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}