1 /* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
4 * We are making the OpenFlow specification and associated documentation
5 * (Software) available for public use and benefit with the expectation
6 * that others will use, modify and enhance the Software and contribute
7 * those enhancements back to the community. However, since we would
8 * like to make the Software available for broadest use, with as few
9 * restrictions as possible permission is hereby granted, free of
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11 * the Software under the copyrights without restriction, including
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13 * distribute, sublicense, and/or sell copies of the Software, and to
14 * permit persons to whom the Software is furnished to do so, subject to
15 * the following conditions:
17 * The above copyright notice and this permission notice shall be
18 * included in all copies or substantial portions of the Software.
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
21 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
22 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
23 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
24 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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29 * The name and trademarks of copyright holder(s) may NOT be used in
30 * advertising or publicity pertaining to the Software or any
31 * derivatives without specific, written prior permission.
34 /* Based on sample implementation in 802.1D-1998. Above copyright and license
35 * applies to all modifications. */
38 #include <arpa/inet.h>
47 #define THIS_MODULE VLM_stp
49 /* Ethernet address used as the destination for STP frames. */
50 const uint8_t stp_eth_addr[ETH_ADDR_LEN]
51 = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x01 };
53 #define STP_PROTOCOL_ID 0x0000
54 #define STP_PROTOCOL_VERSION 0x00
55 #define STP_TYPE_CONFIG 0x00
56 #define STP_TYPE_TCN 0x80
58 struct stp_bpdu_header {
59 uint16_t protocol_id; /* STP_PROTOCOL_ID. */
60 uint8_t protocol_version; /* STP_PROTOCOL_VERSION. */
61 uint8_t bpdu_type; /* One of STP_TYPE_*. */
62 } __attribute__((packed));
63 BUILD_ASSERT_DECL(sizeof(struct stp_bpdu_header) == 4);
65 enum stp_config_bpdu_flags {
66 STP_CONFIG_TOPOLOGY_CHANGE_ACK = 0x80,
67 STP_CONFIG_TOPOLOGY_CHANGE = 0x01
70 struct stp_config_bpdu {
71 struct stp_bpdu_header header; /* Type STP_TYPE_CONFIG. */
72 uint8_t flags; /* STP_CONFIG_* flags. */
73 uint64_t root_id; /* 8.5.1.1: Bridge believed to be root. */
74 uint32_t root_path_cost; /* 8.5.1.2: Cost of path to root. */
75 uint64_t bridge_id; /* 8.5.1.3: ID of transmitting bridge. */
76 uint16_t port_id; /* 8.5.1.4: Port transmitting the BPDU. */
77 uint16_t message_age; /* 8.5.1.5: Age of BPDU at tx time. */
78 uint16_t max_age; /* 8.5.1.6: Timeout for received data. */
79 uint16_t hello_time; /* 8.5.1.7: Time between BPDU generation. */
80 uint16_t forward_delay; /* 8.5.1.8: State progression delay. */
81 } __attribute__((packed));
82 BUILD_ASSERT_DECL(sizeof(struct stp_config_bpdu) == 35);
85 struct stp_bpdu_header header; /* Type STP_TYPE_TCN. */
86 } __attribute__((packed));
87 BUILD_ASSERT_DECL(sizeof(struct stp_tcn_bpdu) == 4);
90 bool active; /* Timer in use? */
91 int value; /* Current value of timer, counting up. */
96 int port_id; /* 8.5.5.1: Unique port identifier. */
97 enum stp_state state; /* 8.5.5.2: Current state. */
98 int path_cost; /* 8.5.5.3: Cost of tx/rx on this port. */
99 stp_identifier designated_root; /* 8.5.5.4. */
100 int designated_cost; /* 8.5.5.5: Path cost to root on port. */
101 stp_identifier designated_bridge; /* 8.5.5.6. */
102 int designated_port; /* 8.5.5.7: Port to send config msgs on. */
103 bool topology_change_ack; /* 8.5.5.8: Flag for next config BPDU. */
104 bool config_pending; /* 8.5.5.9: Send BPDU when hold expires? */
105 bool change_detection_enabled; /* 8.5.5.10: Detect topology changes? */
107 struct stp_timer message_age_timer; /* 8.5.6.1: Age of received info. */
108 struct stp_timer forward_delay_timer; /* 8.5.6.2: State change timer. */
109 struct stp_timer hold_timer; /* 8.5.6.3: BPDU rate limit timer. */
115 /* Static bridge data. */
116 char *name; /* Human-readable name for log messages. */
117 stp_identifier bridge_id; /* 8.5.3.7: This bridge. */
118 int max_age; /* 8.5.3.4: Time to drop received data. */
119 int hello_time; /* 8.5.3.5: Time between sending BPDUs. */
120 int forward_delay; /* 8.5.3.6: Delay between state changes. */
121 int bridge_max_age; /* 8.5.3.8: max_age when we're root. */
122 int bridge_hello_time; /* 8.5.3.9: hello_time as root. */
123 int bridge_forward_delay; /* 8.5.3.10: forward_delay as root. */
125 /* Dynamic bridge data. */
126 stp_identifier designated_root; /* 8.5.3.1: Bridge believed to be root. */
127 unsigned int root_path_cost; /* 8.5.3.2: Cost of path to root. */
128 struct stp_port *root_port; /* 8.5.3.3: Lowest cost port to root. */
129 bool topology_change_detected; /* 8.5.3.11: Detected a topology change? */
130 bool topology_change; /* 8.5.3.12: Received topology change? */
133 struct stp_timer hello_timer; /* 8.5.4.1: Hello timer. */
134 struct stp_timer tcn_timer; /* 8.5.4.2: Topology change timer. */
135 struct stp_timer topology_change_timer; /* 8.5.4.3. */
138 struct stp_port ports[STP_MAX_PORTS];
140 /* Interface to client. */
141 struct stp_port *first_changed_port;
142 void (*send_bpdu)(const void *bpdu, size_t bpdu_size,
143 int port_no, void *aux);
147 #define FOR_EACH_ENABLED_PORT(PORT, STP) \
148 for ((PORT) = stp_next_enabled_port((STP), (STP)->ports); \
150 (PORT) = stp_next_enabled_port((STP), (PORT) + 1))
151 static struct stp_port *
152 stp_next_enabled_port(const struct stp *stp, const struct stp_port *port)
154 for (; port < &stp->ports[ARRAY_SIZE(stp->ports)]; port++) {
155 if (port->state != STP_DISABLED) {
156 return (struct stp_port *) port;
162 #define SECONDS_TO_TIMER(SECS) ((SECS) * 0x100)
164 #define MESSAGE_AGE_INCREMENT 1
166 static void stp_transmit_config(struct stp_port *);
167 static bool stp_supersedes_port_info(const struct stp_port *,
168 const struct stp_config_bpdu *);
169 static void stp_record_config_information(struct stp_port *,
170 const struct stp_config_bpdu *);
171 static void stp_record_config_timeout_values(struct stp *,
172 const struct stp_config_bpdu *);
173 static bool stp_is_designated_port(const struct stp_port *);
174 static void stp_config_bpdu_generation(struct stp *);
175 static void stp_transmit_tcn(struct stp *);
176 static void stp_configuration_update(struct stp *);
177 static bool stp_supersedes_root(const struct stp_port *root,
178 const struct stp_port *);
179 static void stp_root_selection(struct stp *);
180 static void stp_designated_port_selection(struct stp *);
181 static void stp_become_designated_port(struct stp_port *);
182 static void stp_port_state_selection(struct stp *);
183 static void stp_make_forwarding(struct stp_port *);
184 static void stp_make_blocking(struct stp_port *);
185 static void stp_set_port_state(struct stp_port *, enum stp_state);
186 static void stp_topology_change_detection(struct stp *);
187 static void stp_topology_change_acknowledged(struct stp *);
188 static void stp_acknowledge_topology_change(struct stp_port *);
189 static void stp_received_config_bpdu(struct stp *, struct stp_port *,
190 const struct stp_config_bpdu *);
191 static void stp_received_tcn_bpdu(struct stp *, struct stp_port *,
192 const struct stp_tcn_bpdu *);
193 static void stp_hello_timer_expiry(struct stp *);
194 static void stp_message_age_timer_expiry(struct stp_port *);
195 static bool stp_is_designated_for_some_port(const struct stp *);
196 static void stp_forward_delay_timer_expiry(struct stp_port *);
197 static void stp_tcn_timer_expiry(struct stp *);
198 static void stp_topology_change_timer_expiry(struct stp *);
199 static void stp_hold_timer_expiry(struct stp_port *);
200 static void stp_initialize_port(struct stp_port *, enum stp_state);
201 static void stp_become_root_bridge(struct stp *stp);
203 static void stp_start_timer(struct stp_timer *, int value);
204 static void stp_stop_timer(struct stp_timer *);
205 static bool stp_timer_expired(struct stp_timer *, int elapsed, int timeout);
207 /* Creates and returns a new STP instance that initially has no port enabled.
209 * 'bridge_id' should be a 48-bit MAC address as returned by
210 * eth_addr_to_uint64(). 'bridge_id' may also have a priority value in its top
211 * 16 bits; if those bits are set to 0, the default bridge priority of 32768 is
212 * used. (This priority may be changed with stp_set_bridge_priority().)
214 * When the bridge needs to send out a BPDU, it calls 'send_bpdu', passing
215 * 'aux' as auxiliary data. This callback may be called from stp_tick() or
216 * stp_received_bpdu().
219 stp_create(const char *name, stp_identifier bridge_id,
220 void (*send_bpdu)(const void *bpdu, size_t bpdu_size,
221 int port_no, void *aux),
227 stp = xcalloc(1, sizeof *stp);
228 stp->name = xstrdup(name);
229 stp->bridge_id = bridge_id;
230 if (!(stp->bridge_id >> 48)) {
231 stp->bridge_id |= UINT64_C(32768) << 48;
233 stp->max_age = SECONDS_TO_TIMER(6);
234 stp->hello_time = SECONDS_TO_TIMER(2);
235 stp->forward_delay = SECONDS_TO_TIMER(4);
236 stp->bridge_max_age = stp->max_age;
237 stp->bridge_hello_time = stp->hello_time;
238 stp->bridge_forward_delay = stp->forward_delay;
240 stp->designated_root = stp->bridge_id;
241 stp->root_path_cost = 0;
242 stp->root_port = NULL;
243 stp->topology_change_detected = false;
244 stp->topology_change = false;
246 stp_stop_timer(&stp->tcn_timer);
247 stp_stop_timer(&stp->topology_change_timer);
248 stp_start_timer(&stp->hello_timer, 0);
250 stp->send_bpdu = send_bpdu;
253 stp->first_changed_port = &stp->ports[ARRAY_SIZE(stp->ports)];
254 for (p = stp->ports; p < &stp->ports[ARRAY_SIZE(stp->ports)]; p++) {
256 p->port_id = (stp_port_no(p) + 1) | (128 << 8);
257 p->path_cost = 19; /* Recommended default for 100 Mb/s link. */
258 stp_initialize_port(p, STP_DISABLED);
263 /* Destroys 'stp'. */
265 stp_destroy(struct stp *stp)
271 stp_tick(struct stp *stp, int elapsed)
275 if (stp_timer_expired(&stp->hello_timer, elapsed, stp->hello_time)) {
276 stp_hello_timer_expiry(stp);
278 if (stp_timer_expired(&stp->tcn_timer, elapsed, stp->bridge_hello_time)) {
279 stp_tcn_timer_expiry(stp);
281 if (stp_timer_expired(&stp->topology_change_timer, elapsed,
282 stp->max_age + stp->forward_delay)) {
283 stp_topology_change_timer_expiry(stp);
285 FOR_EACH_ENABLED_PORT (p, stp) {
286 if (stp_timer_expired(&p->message_age_timer, elapsed, stp->max_age)) {
287 stp_message_age_timer_expiry(p);
290 FOR_EACH_ENABLED_PORT (p, stp) {
291 if (stp_timer_expired(&p->forward_delay_timer, elapsed,
292 stp->forward_delay)) {
293 stp_forward_delay_timer_expiry(p);
295 if (stp_timer_expired(&p->hold_timer, elapsed, SECONDS_TO_TIMER(1))) {
296 stp_hold_timer_expiry(p);
302 stp_set_bridge_priority(struct stp *stp, uint16_t new_priority)
304 stp_identifier new_bridge_id;
308 new_bridge_id = ((stp->bridge_id & UINT64_C(0xffffffffffff))
309 | ((uint64_t) new_priority << 48));
310 root = stp_is_root_bridge(stp);
311 FOR_EACH_ENABLED_PORT (p, stp) {
312 if (stp_is_designated_port(p)) {
313 p->designated_bridge = new_bridge_id;
316 stp->bridge_id = new_bridge_id;
317 stp_configuration_update(stp);
318 stp_port_state_selection(stp);
319 if (stp_is_root_bridge(stp) && !root) {
320 stp_become_root_bridge(stp);
324 /* Returns the name given to 'stp' in the call to stp_create(). */
326 stp_get_name(const struct stp *stp)
331 /* Returns the bridge ID for 'stp'. */
333 stp_get_bridge_id(const struct stp *stp)
335 return stp->bridge_id;
338 /* Returns the bridge ID of the bridge currently believed to be the root. */
340 stp_get_designated_root(const struct stp *stp)
342 return stp->designated_root;
345 /* Returns true if 'stp' believes itself to the be root of the spanning tree,
346 * false otherwise. */
348 stp_is_root_bridge(const struct stp *stp)
350 return stp->bridge_id == stp->designated_root;
353 /* Returns the cost of the path from 'stp' to the root of the spanning tree. */
355 stp_get_root_path_cost(const struct stp *stp)
357 return stp->root_path_cost;
360 /* Returns the port in 'stp' with index 'port_no', which must be between 0 and
363 stp_get_port(struct stp *stp, int port_no)
365 assert(port_no >= 0 && port_no < ARRAY_SIZE(stp->ports));
366 return &stp->ports[port_no];
369 /* Returns the port connecting 'stp' to the root bridge, or a null pointer if
370 * there is no such port. */
372 stp_get_root_port(struct stp *stp)
374 return stp->root_port;
377 /* Finds a port whose state has changed. If successful, stores the port whose
378 * state changed in '*portp' and returns true. If no port has changed, stores
379 * NULL in '*portp' and returns false. */
381 stp_get_changed_port(struct stp *stp, struct stp_port **portp)
383 struct stp_port *end = &stp->ports[ARRAY_SIZE(stp->ports)];
386 for (p = stp->first_changed_port; p < end; p++) {
387 if (p->state_changed) {
388 p->state_changed = false;
389 stp->first_changed_port = p + 1;
394 stp->first_changed_port = end;
399 /* Returns the name for the given 'state' (for use in debugging and log
402 stp_state_name(enum stp_state state)
420 /* Returns true if 'state' is one in which packets received on a port should
421 * be forwarded, false otherwise. */
423 stp_forward_in_state(enum stp_state state)
425 return state == STP_FORWARDING;
428 /* Returns true if 'state' is one in which MAC learning should be done on
429 * packets received on a port, false otherwise. */
431 stp_learn_in_state(enum stp_state state)
433 return state & (STP_LEARNING | STP_FORWARDING);
436 /* Notifies the STP entity that bridge protocol data unit 'bpdu', which is
437 * 'bpdu_size' bytes in length, was received on port 'p'.
439 * This function may call the 'send_bpdu' function provided to stp_create(). */
441 stp_received_bpdu(struct stp_port *p, const void *bpdu, size_t bpdu_size)
443 struct stp *stp = p->stp;
444 const struct stp_bpdu_header *header;
446 if (p->state == STP_DISABLED) {
450 if (bpdu_size < sizeof(struct stp_bpdu_header)) {
451 VLOG_WARN("%s: received runt %zu-byte BPDU", stp->name, bpdu_size);
456 if (header->protocol_id != htons(STP_PROTOCOL_ID)) {
457 VLOG_WARN("%s: received BPDU with unexpected protocol ID %"PRIu16,
458 stp->name, ntohs(header->protocol_id));
461 if (header->protocol_version != STP_PROTOCOL_VERSION) {
462 VLOG_DBG("%s: received BPDU with unexpected protocol version %"PRIu8,
463 stp->name, header->protocol_version);
466 switch (header->bpdu_type) {
467 case STP_TYPE_CONFIG:
468 if (bpdu_size < sizeof(struct stp_config_bpdu)) {
469 VLOG_WARN("%s: received config BPDU with invalid size %zu",
470 stp->name, bpdu_size);
473 stp_received_config_bpdu(stp, p, bpdu);
477 if (bpdu_size != sizeof(struct stp_tcn_bpdu)) {
478 VLOG_WARN("%s: received TCN BPDU with invalid size %zu",
479 stp->name, bpdu_size);
482 stp_received_tcn_bpdu(stp, p, bpdu);
486 VLOG_WARN("%s: received BPDU of unexpected type %"PRIu8,
487 stp->name, header->bpdu_type);
492 /* Returns the STP entity in which 'p' is nested. */
494 stp_port_get_stp(struct stp_port *p)
499 /* Returns the index of port 'p' within its bridge. */
501 stp_port_no(const struct stp_port *p)
503 struct stp *stp = p->stp;
504 assert(p >= stp->ports && p < &stp->ports[ARRAY_SIZE(stp->ports)]);
505 return p - stp->ports;
508 /* Returns the state of port 'p'. */
510 stp_port_get_state(const struct stp_port *p)
515 /* Disables STP on port 'p'. */
517 stp_port_disable(struct stp_port *p)
519 struct stp *stp = p->stp;
520 if (p->state != STP_DISABLED) {
521 bool root = stp_is_root_bridge(stp);
522 stp_become_designated_port(p);
523 stp_set_port_state(p, STP_DISABLED);
524 p->topology_change_ack = false;
525 p->config_pending = false;
526 stp_stop_timer(&p->message_age_timer);
527 stp_stop_timer(&p->forward_delay_timer);
528 stp_configuration_update(stp);
529 stp_port_state_selection(stp);
530 if (stp_is_root_bridge(stp) && !root) {
531 stp_become_root_bridge(stp);
536 /* Enables STP on port 'p'. The port will initially be in "blocking" state. */
538 stp_port_enable(struct stp_port *p)
540 if (p->state == STP_DISABLED) {
541 stp_initialize_port(p, STP_BLOCKING);
542 stp_port_state_selection(p->stp);
546 /* Sets the priority of port 'p' to 'new_priority'. Lower numerical values
547 * are interpreted as higher priorities. */
549 stp_port_set_priority(struct stp_port *p, uint8_t new_priority)
551 uint16_t new_port_id = (p->port_id & 0xff) | (new_priority << 8);
552 if (p->port_id != new_port_id) {
553 struct stp *stp = p->stp;
554 if (stp_is_designated_port(p)) {
555 p->designated_port = new_port_id;
557 p->port_id = new_port_id;
558 if (stp->bridge_id == p->designated_bridge
559 && p->port_id < p->designated_port) {
560 stp_become_designated_port(p);
561 stp_port_state_selection(stp);
566 /* Sets the path cost of port 'p' to 'path_cost'. Lower values are generally
567 * used to indicate faster links. Use stp_port_set_speed() to automatically
568 * generate a default path cost from a link speed. */
570 stp_port_set_path_cost(struct stp_port *p, unsigned int path_cost)
572 if (p->path_cost != path_cost) {
573 struct stp *stp = p->stp;
574 p->path_cost = path_cost;
575 stp_configuration_update(stp);
576 stp_port_state_selection(stp);
580 /* Sets the path cost of port 'p' based on 'speed' (measured in Mb/s). */
582 stp_port_set_speed(struct stp_port *p, unsigned int speed)
584 stp_port_set_path_cost(p, (speed >= 10000 ? 2 /* 10 Gb/s. */
585 : speed >= 1000 ? 4 /* 1 Gb/s. */
586 : speed >= 100 ? 19 /* 100 Mb/s. */
587 : speed >= 16 ? 62 /* 16 Mb/s. */
588 : speed >= 10 ? 100 /* 10 Mb/s. */
589 : speed >= 4 ? 250 /* 4 Mb/s. */
590 : 19)); /* 100 Mb/s (guess). */
593 /* Enables topology change detection on port 'p'. */
595 stp_port_enable_change_detection(struct stp_port *p)
597 p->change_detection_enabled = true;
600 /* Disables topology change detection on port 'p'. */
602 stp_port_disable_change_detection(struct stp_port *p)
604 p->change_detection_enabled = false;
608 stp_transmit_config(struct stp_port *p)
610 struct stp *stp = p->stp;
611 bool root = stp_is_root_bridge(stp);
612 if (!root && !stp->root_port) {
615 if (p->hold_timer.active) {
616 p->config_pending = true;
618 struct stp_config_bpdu config;
619 memset(&config, 0, sizeof config);
620 config.header.protocol_id = htons(STP_PROTOCOL_ID);
621 config.header.protocol_version = STP_PROTOCOL_VERSION;
622 config.header.bpdu_type = STP_TYPE_CONFIG;
624 if (p->topology_change_ack) {
625 config.flags |= htons(STP_CONFIG_TOPOLOGY_CHANGE_ACK);
627 if (stp->topology_change) {
628 config.flags |= htons(STP_CONFIG_TOPOLOGY_CHANGE);
630 config.root_id = htonll(stp->designated_root);
631 config.root_path_cost = htonl(stp->root_path_cost);
632 config.bridge_id = htonll(stp->bridge_id);
633 config.port_id = htons(p->port_id);
635 config.message_age = htons(0);
637 config.message_age = htons(stp->root_port->message_age_timer.value
638 + MESSAGE_AGE_INCREMENT);
640 config.max_age = htons(stp->max_age);
641 config.hello_time = htons(stp->hello_time);
642 config.forward_delay = htons(stp->forward_delay);
643 if (ntohs(config.message_age) < stp->max_age) {
644 p->topology_change_ack = false;
645 p->config_pending = false;
646 stp->send_bpdu(&config, sizeof config, stp_port_no(p), stp->aux);
647 stp_start_timer(&p->hold_timer, 0);
653 stp_supersedes_port_info(const struct stp_port *p,
654 const struct stp_config_bpdu *config)
656 if (ntohll(config->root_id) != p->designated_root) {
657 return ntohll(config->root_id) < p->designated_root;
658 } else if (ntohl(config->root_path_cost) != p->designated_cost) {
659 return ntohl(config->root_path_cost) < p->designated_cost;
660 } else if (ntohll(config->bridge_id) != p->designated_bridge) {
661 return ntohll(config->bridge_id) < p->designated_bridge;
663 return (ntohll(config->bridge_id) != p->stp->bridge_id
664 || ntohs(config->port_id) <= p->designated_port);
669 stp_record_config_information(struct stp_port *p,
670 const struct stp_config_bpdu *config)
672 p->designated_root = ntohll(config->root_id);
673 p->designated_cost = ntohl(config->root_path_cost);
674 p->designated_bridge = ntohll(config->bridge_id);
675 p->designated_port = ntohs(config->port_id);
676 stp_start_timer(&p->message_age_timer, ntohs(config->message_age));
680 stp_record_config_timeout_values(struct stp *stp,
681 const struct stp_config_bpdu *config)
683 stp->max_age = ntohs(config->max_age);
684 stp->hello_time = ntohs(config->hello_time);
685 stp->forward_delay = ntohs(config->forward_delay);
686 stp->topology_change = config->flags & htons(STP_CONFIG_TOPOLOGY_CHANGE);
690 stp_is_designated_port(const struct stp_port *p)
692 return (p->designated_bridge == p->stp->bridge_id
693 && p->designated_port == p->port_id);
697 stp_config_bpdu_generation(struct stp *stp)
701 FOR_EACH_ENABLED_PORT (p, stp) {
702 if (stp_is_designated_port(p)) {
703 stp_transmit_config(p);
709 stp_transmit_tcn(struct stp *stp)
711 struct stp_port *p = stp->root_port;
712 struct stp_tcn_bpdu tcn_bpdu;
716 tcn_bpdu.header.protocol_id = htons(STP_PROTOCOL_ID);
717 tcn_bpdu.header.protocol_version = STP_PROTOCOL_VERSION;
718 tcn_bpdu.header.bpdu_type = STP_TYPE_TCN;
719 stp->send_bpdu(&tcn_bpdu, sizeof tcn_bpdu, stp_port_no(p), stp->aux);
723 stp_configuration_update(struct stp *stp)
725 stp_root_selection(stp);
726 stp_designated_port_selection(stp);
730 stp_supersedes_root(const struct stp_port *root, const struct stp_port *p)
732 int p_cost = p->designated_cost + p->path_cost;
733 int root_cost = root->designated_cost + root->path_cost;
735 if (p->designated_root != root->designated_root) {
736 return p->designated_root < root->designated_root;
737 } else if (p_cost != root_cost) {
738 return p_cost < root_cost;
739 } else if (p->designated_bridge != root->designated_bridge) {
740 return p->designated_bridge < root->designated_bridge;
741 } else if (p->designated_port != root->designated_port) {
742 return p->designated_port < root->designated_port;
744 return p->port_id < root->port_id;
749 stp_root_selection(struct stp *stp)
751 struct stp_port *p, *root;
754 FOR_EACH_ENABLED_PORT (p, stp) {
755 if (stp_is_designated_port(p)
756 || p->designated_root >= stp->bridge_id) {
759 if (root && !stp_supersedes_root(root, p)) {
764 stp->root_port = root;
766 stp->designated_root = stp->bridge_id;
767 stp->root_path_cost = 0;
769 stp->designated_root = root->designated_root;
770 stp->root_path_cost = root->designated_cost + root->path_cost;
775 stp_designated_port_selection(struct stp *stp)
779 FOR_EACH_ENABLED_PORT (p, stp) {
780 if (stp_is_designated_port(p)
781 || p->designated_root != stp->designated_root
782 || stp->root_path_cost < p->designated_cost
783 || (stp->root_path_cost == p->designated_cost
784 && (stp->bridge_id < p->designated_bridge
785 || (stp->bridge_id == p->designated_bridge
786 && p->port_id <= p->designated_port))))
788 stp_become_designated_port(p);
794 stp_become_designated_port(struct stp_port *p)
796 struct stp *stp = p->stp;
797 p->designated_root = stp->designated_root;
798 p->designated_cost = stp->root_path_cost;
799 p->designated_bridge = stp->bridge_id;
800 p->designated_port = p->port_id;
804 stp_port_state_selection(struct stp *stp)
808 FOR_EACH_ENABLED_PORT (p, stp) {
809 if (p == stp->root_port) {
810 p->config_pending = false;
811 p->topology_change_ack = false;
812 stp_make_forwarding(p);
813 } else if (stp_is_designated_port(p)) {
814 stp_stop_timer(&p->message_age_timer);
815 stp_make_forwarding(p);
817 p->config_pending = false;
818 p->topology_change_ack = false;
819 stp_make_blocking(p);
825 stp_make_forwarding(struct stp_port *p)
827 if (p->state == STP_BLOCKING) {
828 stp_set_port_state(p, STP_LISTENING);
829 stp_start_timer(&p->forward_delay_timer, 0);
834 stp_make_blocking(struct stp_port *p)
836 if (!(p->state & (STP_DISABLED | STP_BLOCKING))) {
837 if (p->state & (STP_FORWARDING | STP_LEARNING)) {
838 if (p->change_detection_enabled) {
839 stp_topology_change_detection(p->stp);
842 stp_set_port_state(p, STP_BLOCKING);
843 stp_stop_timer(&p->forward_delay_timer);
848 stp_set_port_state(struct stp_port *p, enum stp_state state)
850 if (state != p->state && !p->state_changed) {
851 p->state_changed = true;
852 if (p < p->stp->first_changed_port) {
853 p->stp->first_changed_port = p;
860 stp_topology_change_detection(struct stp *stp)
862 if (stp_is_root_bridge(stp)) {
863 stp->topology_change = true;
864 stp_start_timer(&stp->topology_change_timer, 0);
865 } else if (!stp->topology_change_detected) {
866 stp_transmit_tcn(stp);
867 stp_start_timer(&stp->tcn_timer, 0);
869 stp->topology_change_detected = true;
873 stp_topology_change_acknowledged(struct stp *stp)
875 stp->topology_change_detected = false;
876 stp_stop_timer(&stp->tcn_timer);
880 stp_acknowledge_topology_change(struct stp_port *p)
882 p->topology_change_ack = true;
883 stp_transmit_config(p);
887 stp_received_config_bpdu(struct stp *stp, struct stp_port *p,
888 const struct stp_config_bpdu *config)
890 if (ntohs(config->message_age) >= ntohs(config->max_age)) {
891 VLOG_WARN("%s: received config BPDU with message age (%u) greater "
894 ntohs(config->message_age), ntohs(config->max_age));
897 if (p->state != STP_DISABLED) {
898 bool root = stp_is_root_bridge(stp);
899 if (stp_supersedes_port_info(p, config)) {
900 stp_record_config_information(p, config);
901 stp_configuration_update(stp);
902 stp_port_state_selection(stp);
903 if (!stp_is_root_bridge(stp) && root) {
904 stp_stop_timer(&stp->hello_timer);
905 if (stp->topology_change_detected) {
906 stp_stop_timer(&stp->topology_change_timer);
907 stp_transmit_tcn(stp);
908 stp_start_timer(&stp->tcn_timer, 0);
911 if (p == stp->root_port) {
912 stp_record_config_timeout_values(stp, config);
913 stp_config_bpdu_generation(stp);
914 if (config->flags & htons(STP_CONFIG_TOPOLOGY_CHANGE_ACK)) {
915 stp_topology_change_acknowledged(stp);
918 } else if (stp_is_designated_port(p)) {
919 stp_transmit_config(p);
925 stp_received_tcn_bpdu(struct stp *stp, struct stp_port *p,
926 const struct stp_tcn_bpdu *tcn)
928 if (p->state != STP_DISABLED) {
929 if (stp_is_designated_port(p)) {
930 stp_topology_change_detection(stp);
931 stp_acknowledge_topology_change(p);
937 stp_hello_timer_expiry(struct stp *stp)
939 stp_config_bpdu_generation(stp);
940 stp_start_timer(&stp->hello_timer, 0);
944 stp_message_age_timer_expiry(struct stp_port *p)
946 struct stp *stp = p->stp;
947 bool root = stp_is_root_bridge(stp);
948 stp_become_designated_port(p);
949 stp_configuration_update(stp);
950 stp_port_state_selection(stp);
951 if (stp_is_root_bridge(stp) && !root) {
952 stp->max_age = stp->bridge_max_age;
953 stp->hello_time = stp->bridge_hello_time;
954 stp->forward_delay = stp->bridge_forward_delay;
955 stp_topology_change_detection(stp);
956 stp_stop_timer(&stp->tcn_timer);
957 stp_config_bpdu_generation(stp);
958 stp_start_timer(&stp->hello_timer, 0);
963 stp_is_designated_for_some_port(const struct stp *stp)
965 const struct stp_port *p;
967 FOR_EACH_ENABLED_PORT (p, stp) {
968 if (p->designated_bridge == stp->bridge_id) {
976 stp_forward_delay_timer_expiry(struct stp_port *p)
978 if (p->state == STP_LISTENING) {
979 stp_set_port_state(p, STP_LEARNING);
980 stp_start_timer(&p->forward_delay_timer, 0);
981 } else if (p->state == STP_LEARNING) {
982 stp_set_port_state(p, STP_FORWARDING);
983 if (stp_is_designated_for_some_port(p->stp)) {
984 if (p->change_detection_enabled) {
985 stp_topology_change_detection(p->stp);
992 stp_tcn_timer_expiry(struct stp *stp)
994 stp_transmit_tcn(stp);
995 stp_start_timer(&stp->tcn_timer, 0);
999 stp_topology_change_timer_expiry(struct stp *stp)
1001 stp->topology_change_detected = false;
1002 stp->topology_change = false;
1006 stp_hold_timer_expiry(struct stp_port *p)
1008 if (p->config_pending) {
1009 stp_transmit_config(p);
1014 stp_initialize_port(struct stp_port *p, enum stp_state state)
1016 assert(state & (STP_DISABLED | STP_BLOCKING));
1017 stp_become_designated_port(p);
1018 stp_set_port_state(p, state);
1019 p->topology_change_ack = false;
1020 p->config_pending = false;
1021 p->change_detection_enabled = true;
1022 stp_stop_timer(&p->message_age_timer);
1023 stp_stop_timer(&p->forward_delay_timer);
1024 stp_stop_timer(&p->hold_timer);
1028 stp_become_root_bridge(struct stp *stp)
1030 stp->max_age = stp->bridge_max_age;
1031 stp->hello_time = stp->bridge_hello_time;
1032 stp->forward_delay = stp->bridge_forward_delay;
1033 stp_topology_change_detection(stp);
1034 stp_stop_timer(&stp->tcn_timer);
1035 stp_config_bpdu_generation(stp);
1036 stp_start_timer(&stp->hello_timer, 0);
1040 stp_start_timer(struct stp_timer *timer, int value)
1042 timer->value = value;
1043 timer->active = true;
1047 stp_stop_timer(struct stp_timer *timer)
1049 timer->active = false;
1053 stp_timer_expired(struct stp_timer *timer, int elapsed, int timeout)
1055 if (timer->active) {
1056 timer->value += elapsed;
1057 if (timer->value >= timeout) {
1058 timer->active = false;