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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Spanning tree protocol; generic parts
4 * Linux ethernet bridge
5 *
6 * Authors:
7 * Lennert Buytenhek <buytenh@gnu.org>
8 */
9#include <linux/kernel.h>
10#include <linux/rculist.h>
11#include <net/switchdev.h>
12
13#include "br_private.h"
14#include "br_private_stp.h"
15
16/* since time values in bpdu are in jiffies and then scaled (1/256)
17 * before sending, make sure that is at least one STP tick.
18 */
19#define MESSAGE_AGE_INCR ((HZ / 256) + 1)
20
21static const char *const br_port_state_names[] = {
22 [BR_STATE_DISABLED] = "disabled",
23 [BR_STATE_LISTENING] = "listening",
24 [BR_STATE_LEARNING] = "learning",
25 [BR_STATE_FORWARDING] = "forwarding",
26 [BR_STATE_BLOCKING] = "blocking",
27};
28
29void br_set_state(struct net_bridge_port *p, unsigned int state)
30{
31 struct switchdev_attr attr = {
32 .orig_dev = p->dev,
33 .id = SWITCHDEV_ATTR_ID_PORT_STP_STATE,
34 .flags = SWITCHDEV_F_DEFER,
35 .u.stp_state = state,
36 };
37 int err;
38
39 p->state = state;
40 err = switchdev_port_attr_set(p->dev, &attr);
41 if (err && err != -EOPNOTSUPP)
42 br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
43 (unsigned int) p->port_no, p->dev->name);
44 else
45 br_info(p->br, "port %u(%s) entered %s state\n",
46 (unsigned int) p->port_no, p->dev->name,
47 br_port_state_names[p->state]);
48}
49
50/* called under bridge lock */
51struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no)
52{
53 struct net_bridge_port *p;
54
55 list_for_each_entry_rcu(p, &br->port_list, list) {
56 if (p->port_no == port_no)
57 return p;
58 }
59
60 return NULL;
61}
62
63/* called under bridge lock */
64static int br_should_become_root_port(const struct net_bridge_port *p,
65 u16 root_port)
66{
67 struct net_bridge *br;
68 struct net_bridge_port *rp;
69 int t;
70
71 br = p->br;
72 if (p->state == BR_STATE_DISABLED ||
73 br_is_designated_port(p))
74 return 0;
75
76 if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0)
77 return 0;
78
79 if (!root_port)
80 return 1;
81
82 rp = br_get_port(br, root_port);
83
84 t = memcmp(&p->designated_root, &rp->designated_root, 8);
85 if (t < 0)
86 return 1;
87 else if (t > 0)
88 return 0;
89
90 if (p->designated_cost + p->path_cost <
91 rp->designated_cost + rp->path_cost)
92 return 1;
93 else if (p->designated_cost + p->path_cost >
94 rp->designated_cost + rp->path_cost)
95 return 0;
96
97 t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8);
98 if (t < 0)
99 return 1;
100 else if (t > 0)
101 return 0;
102
103 if (p->designated_port < rp->designated_port)
104 return 1;
105 else if (p->designated_port > rp->designated_port)
106 return 0;
107
108 if (p->port_id < rp->port_id)
109 return 1;
110
111 return 0;
112}
113
114static void br_root_port_block(const struct net_bridge *br,
115 struct net_bridge_port *p)
116{
117
118 br_notice(br, "port %u(%s) tried to become root port (blocked)",
119 (unsigned int) p->port_no, p->dev->name);
120
121 br_set_state(p, BR_STATE_LISTENING);
122 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
123
124 if (br->forward_delay > 0)
125 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
126}
127
128/* called under bridge lock */
129static void br_root_selection(struct net_bridge *br)
130{
131 struct net_bridge_port *p;
132 u16 root_port = 0;
133
134 list_for_each_entry(p, &br->port_list, list) {
135 if (!br_should_become_root_port(p, root_port))
136 continue;
137
138 if (p->flags & BR_ROOT_BLOCK)
139 br_root_port_block(br, p);
140 else
141 root_port = p->port_no;
142 }
143
144 br->root_port = root_port;
145
146 if (!root_port) {
147 br->designated_root = br->bridge_id;
148 br->root_path_cost = 0;
149 } else {
150 p = br_get_port(br, root_port);
151 br->designated_root = p->designated_root;
152 br->root_path_cost = p->designated_cost + p->path_cost;
153 }
154}
155
156/* called under bridge lock */
157void br_become_root_bridge(struct net_bridge *br)
158{
159 br->max_age = br->bridge_max_age;
160 br->hello_time = br->bridge_hello_time;
161 br->forward_delay = br->bridge_forward_delay;
162 br_topology_change_detection(br);
163 del_timer(&br->tcn_timer);
164
165 if (br->dev->flags & IFF_UP) {
166 br_config_bpdu_generation(br);
167 mod_timer(&br->hello_timer, jiffies + br->hello_time);
168 }
169}
170
171/* called under bridge lock */
172void br_transmit_config(struct net_bridge_port *p)
173{
174 struct br_config_bpdu bpdu;
175 struct net_bridge *br;
176
177 if (timer_pending(&p->hold_timer)) {
178 p->config_pending = 1;
179 return;
180 }
181
182 br = p->br;
183
184 bpdu.topology_change = br->topology_change;
185 bpdu.topology_change_ack = p->topology_change_ack;
186 bpdu.root = br->designated_root;
187 bpdu.root_path_cost = br->root_path_cost;
188 bpdu.bridge_id = br->bridge_id;
189 bpdu.port_id = p->port_id;
190 if (br_is_root_bridge(br))
191 bpdu.message_age = 0;
192 else {
193 struct net_bridge_port *root
194 = br_get_port(br, br->root_port);
195 bpdu.message_age = (jiffies - root->designated_age)
196 + MESSAGE_AGE_INCR;
197 }
198 bpdu.max_age = br->max_age;
199 bpdu.hello_time = br->hello_time;
200 bpdu.forward_delay = br->forward_delay;
201
202 if (bpdu.message_age < br->max_age) {
203 br_send_config_bpdu(p, &bpdu);
204 p->topology_change_ack = 0;
205 p->config_pending = 0;
206 if (p->br->stp_enabled == BR_KERNEL_STP)
207 mod_timer(&p->hold_timer,
208 round_jiffies(jiffies + BR_HOLD_TIME));
209 }
210}
211
212/* called under bridge lock */
213static void br_record_config_information(struct net_bridge_port *p,
214 const struct br_config_bpdu *bpdu)
215{
216 p->designated_root = bpdu->root;
217 p->designated_cost = bpdu->root_path_cost;
218 p->designated_bridge = bpdu->bridge_id;
219 p->designated_port = bpdu->port_id;
220 p->designated_age = jiffies - bpdu->message_age;
221
222 mod_timer(&p->message_age_timer, jiffies
223 + (bpdu->max_age - bpdu->message_age));
224}
225
226/* called under bridge lock */
227static void br_record_config_timeout_values(struct net_bridge *br,
228 const struct br_config_bpdu *bpdu)
229{
230 br->max_age = bpdu->max_age;
231 br->hello_time = bpdu->hello_time;
232 br->forward_delay = bpdu->forward_delay;
233 __br_set_topology_change(br, bpdu->topology_change);
234}
235
236/* called under bridge lock */
237void br_transmit_tcn(struct net_bridge *br)
238{
239 struct net_bridge_port *p;
240
241 p = br_get_port(br, br->root_port);
242 if (p)
243 br_send_tcn_bpdu(p);
244 else
245 br_notice(br, "root port %u not found for topology notice\n",
246 br->root_port);
247}
248
249/* called under bridge lock */
250static int br_should_become_designated_port(const struct net_bridge_port *p)
251{
252 struct net_bridge *br;
253 int t;
254
255 br = p->br;
256 if (br_is_designated_port(p))
257 return 1;
258
259 if (memcmp(&p->designated_root, &br->designated_root, 8))
260 return 1;
261
262 if (br->root_path_cost < p->designated_cost)
263 return 1;
264 else if (br->root_path_cost > p->designated_cost)
265 return 0;
266
267 t = memcmp(&br->bridge_id, &p->designated_bridge, 8);
268 if (t < 0)
269 return 1;
270 else if (t > 0)
271 return 0;
272
273 if (p->port_id < p->designated_port)
274 return 1;
275
276 return 0;
277}
278
279/* called under bridge lock */
280static void br_designated_port_selection(struct net_bridge *br)
281{
282 struct net_bridge_port *p;
283
284 list_for_each_entry(p, &br->port_list, list) {
285 if (p->state != BR_STATE_DISABLED &&
286 br_should_become_designated_port(p))
287 br_become_designated_port(p);
288
289 }
290}
291
292/* called under bridge lock */
293static int br_supersedes_port_info(const struct net_bridge_port *p,
294 const struct br_config_bpdu *bpdu)
295{
296 int t;
297
298 t = memcmp(&bpdu->root, &p->designated_root, 8);
299 if (t < 0)
300 return 1;
301 else if (t > 0)
302 return 0;
303
304 if (bpdu->root_path_cost < p->designated_cost)
305 return 1;
306 else if (bpdu->root_path_cost > p->designated_cost)
307 return 0;
308
309 t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8);
310 if (t < 0)
311 return 1;
312 else if (t > 0)
313 return 0;
314
315 if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8))
316 return 1;
317
318 if (bpdu->port_id <= p->designated_port)
319 return 1;
320
321 return 0;
322}
323
324/* called under bridge lock */
325static void br_topology_change_acknowledged(struct net_bridge *br)
326{
327 br->topology_change_detected = 0;
328 del_timer(&br->tcn_timer);
329}
330
331/* called under bridge lock */
332void br_topology_change_detection(struct net_bridge *br)
333{
334 int isroot = br_is_root_bridge(br);
335
336 if (br->stp_enabled != BR_KERNEL_STP)
337 return;
338
339 br_info(br, "topology change detected, %s\n",
340 isroot ? "propagating" : "sending tcn bpdu");
341
342 if (isroot) {
343 __br_set_topology_change(br, 1);
344 mod_timer(&br->topology_change_timer, jiffies
345 + br->bridge_forward_delay + br->bridge_max_age);
346 } else if (!br->topology_change_detected) {
347 br_transmit_tcn(br);
348 mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time);
349 }
350
351 br->topology_change_detected = 1;
352}
353
354/* called under bridge lock */
355void br_config_bpdu_generation(struct net_bridge *br)
356{
357 struct net_bridge_port *p;
358
359 list_for_each_entry(p, &br->port_list, list) {
360 if (p->state != BR_STATE_DISABLED &&
361 br_is_designated_port(p))
362 br_transmit_config(p);
363 }
364}
365
366/* called under bridge lock */
367static void br_reply(struct net_bridge_port *p)
368{
369 br_transmit_config(p);
370}
371
372/* called under bridge lock */
373void br_configuration_update(struct net_bridge *br)
374{
375 br_root_selection(br);
376 br_designated_port_selection(br);
377}
378
379/* called under bridge lock */
380void br_become_designated_port(struct net_bridge_port *p)
381{
382 struct net_bridge *br;
383
384 br = p->br;
385 p->designated_root = br->designated_root;
386 p->designated_cost = br->root_path_cost;
387 p->designated_bridge = br->bridge_id;
388 p->designated_port = p->port_id;
389}
390
391
392/* called under bridge lock */
393static void br_make_blocking(struct net_bridge_port *p)
394{
395 if (p->state != BR_STATE_DISABLED &&
396 p->state != BR_STATE_BLOCKING) {
397 if (p->state == BR_STATE_FORWARDING ||
398 p->state == BR_STATE_LEARNING)
399 br_topology_change_detection(p->br);
400
401 br_set_state(p, BR_STATE_BLOCKING);
402 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
403
404 del_timer(&p->forward_delay_timer);
405 }
406}
407
408/* called under bridge lock */
409static void br_make_forwarding(struct net_bridge_port *p)
410{
411 struct net_bridge *br = p->br;
412
413 if (p->state != BR_STATE_BLOCKING)
414 return;
415
416 if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) {
417 br_set_state(p, BR_STATE_FORWARDING);
418 br_topology_change_detection(br);
419 del_timer(&p->forward_delay_timer);
420 } else if (br->stp_enabled == BR_KERNEL_STP)
421 br_set_state(p, BR_STATE_LISTENING);
422 else
423 br_set_state(p, BR_STATE_LEARNING);
424
425 br_ifinfo_notify(RTM_NEWLINK, NULL, p);
426
427 if (br->forward_delay != 0)
428 mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay);
429}
430
431/* called under bridge lock */
432void br_port_state_selection(struct net_bridge *br)
433{
434 struct net_bridge_port *p;
435 unsigned int liveports = 0;
436
437 list_for_each_entry(p, &br->port_list, list) {
438 if (p->state == BR_STATE_DISABLED)
439 continue;
440
441 /* Don't change port states if userspace is handling STP */
442 if (br->stp_enabled != BR_USER_STP) {
443 if (p->port_no == br->root_port) {
444 p->config_pending = 0;
445 p->topology_change_ack = 0;
446 br_make_forwarding(p);
447 } else if (br_is_designated_port(p)) {
448 del_timer(&p->message_age_timer);
449 br_make_forwarding(p);
450 } else {
451 p->config_pending = 0;
452 p->topology_change_ack = 0;
453 br_make_blocking(p);
454 }
455 }
456
457 if (p->state != BR_STATE_BLOCKING)
458 br_multicast_enable_port(p);
459 /* Multicast is not disabled for the port when it goes in
460 * blocking state because the timers will expire and stop by
461 * themselves without sending more queries.
462 */
463 if (p->state == BR_STATE_FORWARDING)
464 ++liveports;
465 }
466
467 if (liveports == 0)
468 netif_carrier_off(br->dev);
469 else
470 netif_carrier_on(br->dev);
471}
472
473/* called under bridge lock */
474static void br_topology_change_acknowledge(struct net_bridge_port *p)
475{
476 p->topology_change_ack = 1;
477 br_transmit_config(p);
478}
479
480/* called under bridge lock */
481void br_received_config_bpdu(struct net_bridge_port *p,
482 const struct br_config_bpdu *bpdu)
483{
484 struct net_bridge *br;
485 int was_root;
486
487 br = p->br;
488 was_root = br_is_root_bridge(br);
489
490 if (br_supersedes_port_info(p, bpdu)) {
491 br_record_config_information(p, bpdu);
492 br_configuration_update(br);
493 br_port_state_selection(br);
494
495 if (!br_is_root_bridge(br) && was_root) {
496 del_timer(&br->hello_timer);
497 if (br->topology_change_detected) {
498 del_timer(&br->topology_change_timer);
499 br_transmit_tcn(br);
500
501 mod_timer(&br->tcn_timer,
502 jiffies + br->bridge_hello_time);
503 }
504 }
505
506 if (p->port_no == br->root_port) {
507 br_record_config_timeout_values(br, bpdu);
508 br_config_bpdu_generation(br);
509 if (bpdu->topology_change_ack)
510 br_topology_change_acknowledged(br);
511 }
512 } else if (br_is_designated_port(p)) {
513 br_reply(p);
514 }
515}
516
517/* called under bridge lock */
518void br_received_tcn_bpdu(struct net_bridge_port *p)
519{
520 if (br_is_designated_port(p)) {
521 br_info(p->br, "port %u(%s) received tcn bpdu\n",
522 (unsigned int) p->port_no, p->dev->name);
523
524 br_topology_change_detection(p->br);
525 br_topology_change_acknowledge(p);
526 }
527}
528
529/* Change bridge STP parameter */
530int br_set_hello_time(struct net_bridge *br, unsigned long val)
531{
532 unsigned long t = clock_t_to_jiffies(val);
533
534 if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME)
535 return -ERANGE;
536
537 spin_lock_bh(&br->lock);
538 br->bridge_hello_time = t;
539 if (br_is_root_bridge(br))
540 br->hello_time = br->bridge_hello_time;
541 spin_unlock_bh(&br->lock);
542 return 0;
543}
544
545int br_set_max_age(struct net_bridge *br, unsigned long val)
546{
547 unsigned long t = clock_t_to_jiffies(val);
548
549 if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE)
550 return -ERANGE;
551
552 spin_lock_bh(&br->lock);
553 br->bridge_max_age = t;
554 if (br_is_root_bridge(br))
555 br->max_age = br->bridge_max_age;
556 spin_unlock_bh(&br->lock);
557 return 0;
558
559}
560
561/* called under bridge lock */
562int __set_ageing_time(struct net_device *dev, unsigned long t)
563{
564 struct switchdev_attr attr = {
565 .orig_dev = dev,
566 .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
567 .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER,
568 .u.ageing_time = jiffies_to_clock_t(t),
569 };
570 int err;
571
572 err = switchdev_port_attr_set(dev, &attr);
573 if (err && err != -EOPNOTSUPP)
574 return err;
575
576 return 0;
577}
578
579/* Set time interval that dynamic forwarding entries live
580 * For pure software bridge, allow values outside the 802.1
581 * standard specification for special cases:
582 * 0 - entry never ages (all permanant)
583 * 1 - entry disappears (no persistance)
584 *
585 * Offloaded switch entries maybe more restrictive
586 */
587int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time)
588{
589 unsigned long t = clock_t_to_jiffies(ageing_time);
590 int err;
591
592 err = __set_ageing_time(br->dev, t);
593 if (err)
594 return err;
595
596 spin_lock_bh(&br->lock);
597 br->bridge_ageing_time = t;
598 br->ageing_time = t;
599 spin_unlock_bh(&br->lock);
600
601 mod_delayed_work(system_long_wq, &br->gc_work, 0);
602
603 return 0;
604}
605
606/* called under bridge lock */
607void __br_set_topology_change(struct net_bridge *br, unsigned char val)
608{
609 unsigned long t;
610 int err;
611
612 if (br->stp_enabled == BR_KERNEL_STP && br->topology_change != val) {
613 /* On topology change, set the bridge ageing time to twice the
614 * forward delay. Otherwise, restore its default ageing time.
615 */
616
617 if (val) {
618 t = 2 * br->forward_delay;
619 br_debug(br, "decreasing ageing time to %lu\n", t);
620 } else {
621 t = br->bridge_ageing_time;
622 br_debug(br, "restoring ageing time to %lu\n", t);
623 }
624
625 err = __set_ageing_time(br->dev, t);
626 if (err)
627 br_warn(br, "error offloading ageing time\n");
628 else
629 br->ageing_time = t;
630 }
631
632 br->topology_change = val;
633}
634
635void __br_set_forward_delay(struct net_bridge *br, unsigned long t)
636{
637 br->bridge_forward_delay = t;
638 if (br_is_root_bridge(br))
639 br->forward_delay = br->bridge_forward_delay;
640}
641
642int br_set_forward_delay(struct net_bridge *br, unsigned long val)
643{
644 unsigned long t = clock_t_to_jiffies(val);
645 int err = -ERANGE;
646
647 spin_lock_bh(&br->lock);
648 if (br->stp_enabled != BR_NO_STP &&
649 (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY))
650 goto unlock;
651
652 __br_set_forward_delay(br, t);
653 err = 0;
654
655unlock:
656 spin_unlock_bh(&br->lock);
657 return err;
658}
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}