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