Loading...
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/*
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}