2 * Copyright (c) 2008, 2009, 2010 Nicira Networks.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 /* Based on sample implementation in 802.1D-1998. Above copyright and license
18 * applies to all modifications. */
21 #include <sys/types.h>
22 #include <netinet/in.h>
23 #include <arpa/inet.h>
33 #define THIS_MODULE VLM_stp
35 /* Ethernet address used as the destination for STP frames. */
36 const uint8_t stp_eth_addr
[ETH_ADDR_LEN
]
37 = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x01 };
39 #define STP_PROTOCOL_ID 0x0000
40 #define STP_PROTOCOL_VERSION 0x00
41 #define STP_TYPE_CONFIG 0x00
42 #define STP_TYPE_TCN 0x80
44 struct stp_bpdu_header
{
45 uint16_t protocol_id
; /* STP_PROTOCOL_ID. */
46 uint8_t protocol_version
; /* STP_PROTOCOL_VERSION. */
47 uint8_t bpdu_type
; /* One of STP_TYPE_*. */
48 } __attribute__((packed
));
49 BUILD_ASSERT_DECL(sizeof(struct stp_bpdu_header
) == 4);
51 enum stp_config_bpdu_flags
{
52 STP_CONFIG_TOPOLOGY_CHANGE_ACK
= 0x80,
53 STP_CONFIG_TOPOLOGY_CHANGE
= 0x01
56 struct stp_config_bpdu
{
57 struct stp_bpdu_header header
; /* Type STP_TYPE_CONFIG. */
58 uint8_t flags
; /* STP_CONFIG_* flags. */
59 uint64_t root_id
; /* 8.5.1.1: Bridge believed to be root. */
60 uint32_t root_path_cost
; /* 8.5.1.2: Cost of path to root. */
61 uint64_t bridge_id
; /* 8.5.1.3: ID of transmitting bridge. */
62 uint16_t port_id
; /* 8.5.1.4: Port transmitting the BPDU. */
63 uint16_t message_age
; /* 8.5.1.5: Age of BPDU at tx time. */
64 uint16_t max_age
; /* 8.5.1.6: Timeout for received data. */
65 uint16_t hello_time
; /* 8.5.1.7: Time between BPDU generation. */
66 uint16_t forward_delay
; /* 8.5.1.8: State progression delay. */
67 } __attribute__((packed
));
68 BUILD_ASSERT_DECL(sizeof(struct stp_config_bpdu
) == 35);
71 struct stp_bpdu_header header
; /* Type STP_TYPE_TCN. */
72 } __attribute__((packed
));
73 BUILD_ASSERT_DECL(sizeof(struct stp_tcn_bpdu
) == 4);
76 bool active
; /* Timer in use? */
77 int value
; /* Current value of timer, counting up. */
82 int port_id
; /* 8.5.5.1: Unique port identifier. */
83 enum stp_state state
; /* 8.5.5.2: Current state. */
84 int path_cost
; /* 8.5.5.3: Cost of tx/rx on this port. */
85 stp_identifier designated_root
; /* 8.5.5.4. */
86 int designated_cost
; /* 8.5.5.5: Path cost to root on port. */
87 stp_identifier designated_bridge
; /* 8.5.5.6. */
88 int designated_port
; /* 8.5.5.7: Port to send config msgs on. */
89 bool topology_change_ack
; /* 8.5.5.8: Flag for next config BPDU. */
90 bool config_pending
; /* 8.5.5.9: Send BPDU when hold expires? */
91 bool change_detection_enabled
; /* 8.5.5.10: Detect topology changes? */
93 struct stp_timer message_age_timer
; /* 8.5.6.1: Age of received info. */
94 struct stp_timer forward_delay_timer
; /* 8.5.6.2: State change timer. */
95 struct stp_timer hold_timer
; /* 8.5.6.3: BPDU rate limit timer. */
101 /* Static bridge data. */
102 char *name
; /* Human-readable name for log messages. */
103 stp_identifier bridge_id
; /* 8.5.3.7: This bridge. */
104 int max_age
; /* 8.5.3.4: Time to drop received data. */
105 int hello_time
; /* 8.5.3.5: Time between sending BPDUs. */
106 int forward_delay
; /* 8.5.3.6: Delay between state changes. */
107 int bridge_max_age
; /* 8.5.3.8: max_age when we're root. */
108 int bridge_hello_time
; /* 8.5.3.9: hello_time as root. */
109 int bridge_forward_delay
; /* 8.5.3.10: forward_delay as root. */
110 int rq_max_age
; /* User-requested max age, in ms. */
111 int rq_hello_time
; /* User-requested hello time, in ms. */
112 int rq_forward_delay
; /* User-requested forward delay, in ms. */
113 int elapsed_remainder
; /* Left-over msecs from last stp_tick(). */
115 /* Dynamic bridge data. */
116 stp_identifier designated_root
; /* 8.5.3.1: Bridge believed to be root. */
117 unsigned int root_path_cost
; /* 8.5.3.2: Cost of path to root. */
118 struct stp_port
*root_port
; /* 8.5.3.3: Lowest cost port to root. */
119 bool topology_change_detected
; /* 8.5.3.11: Detected a topology change? */
120 bool topology_change
; /* 8.5.3.12: Received topology change? */
123 struct stp_timer hello_timer
; /* 8.5.4.1: Hello timer. */
124 struct stp_timer tcn_timer
; /* 8.5.4.2: Topology change timer. */
125 struct stp_timer topology_change_timer
; /* 8.5.4.3. */
128 struct stp_port ports
[STP_MAX_PORTS
];
130 /* Interface to client. */
131 struct stp_port
*first_changed_port
;
132 void (*send_bpdu
)(struct ofpbuf
*bpdu
, int port_no
, void *aux
);
136 #define FOR_EACH_ENABLED_PORT(PORT, STP) \
137 for ((PORT) = stp_next_enabled_port((STP), (STP)->ports); \
139 (PORT) = stp_next_enabled_port((STP), (PORT) + 1))
140 static struct stp_port
*
141 stp_next_enabled_port(const struct stp
*stp
, const struct stp_port
*port
)
143 for (; port
< &stp
->ports
[ARRAY_SIZE(stp
->ports
)]; port
++) {
144 if (port
->state
!= STP_DISABLED
) {
145 return (struct stp_port
*) port
;
151 #define MESSAGE_AGE_INCREMENT 1
153 static void stp_transmit_config(struct stp_port
*);
154 static bool stp_supersedes_port_info(const struct stp_port
*,
155 const struct stp_config_bpdu
*);
156 static void stp_record_config_information(struct stp_port
*,
157 const struct stp_config_bpdu
*);
158 static void stp_record_config_timeout_values(struct stp
*,
159 const struct stp_config_bpdu
*);
160 static bool stp_is_designated_port(const struct stp_port
*);
161 static void stp_config_bpdu_generation(struct stp
*);
162 static void stp_transmit_tcn(struct stp
*);
163 static void stp_configuration_update(struct stp
*);
164 static bool stp_supersedes_root(const struct stp_port
*root
,
165 const struct stp_port
*);
166 static void stp_root_selection(struct stp
*);
167 static void stp_designated_port_selection(struct stp
*);
168 static void stp_become_designated_port(struct stp_port
*);
169 static void stp_port_state_selection(struct stp
*);
170 static void stp_make_forwarding(struct stp_port
*);
171 static void stp_make_blocking(struct stp_port
*);
172 static void stp_set_port_state(struct stp_port
*, enum stp_state
);
173 static void stp_topology_change_detection(struct stp
*);
174 static void stp_topology_change_acknowledged(struct stp
*);
175 static void stp_acknowledge_topology_change(struct stp_port
*);
176 static void stp_received_config_bpdu(struct stp
*, struct stp_port
*,
177 const struct stp_config_bpdu
*);
178 static void stp_received_tcn_bpdu(struct stp
*, struct stp_port
*);
179 static void stp_hello_timer_expiry(struct stp
*);
180 static void stp_message_age_timer_expiry(struct stp_port
*);
181 static bool stp_is_designated_for_some_port(const struct stp
*);
182 static void stp_forward_delay_timer_expiry(struct stp_port
*);
183 static void stp_tcn_timer_expiry(struct stp
*);
184 static void stp_topology_change_timer_expiry(struct stp
*);
185 static void stp_hold_timer_expiry(struct stp_port
*);
186 static void stp_initialize_port(struct stp_port
*, enum stp_state
);
187 static void stp_become_root_bridge(struct stp
*);
188 static void stp_update_bridge_timers(struct stp
*);
190 static int clamp(int x
, int min
, int max
);
191 static int ms_to_timer(int ms
);
192 static int ms_to_timer_remainder(int ms
);
193 static int timer_to_ms(int timer
);
194 static void stp_start_timer(struct stp_timer
*, int value
);
195 static void stp_stop_timer(struct stp_timer
*);
196 static bool stp_timer_expired(struct stp_timer
*, int elapsed
, int timeout
);
198 static void stp_send_bpdu(struct stp_port
*, const void *, size_t);
200 /* Creates and returns a new STP instance that initially has no ports enabled.
202 * 'bridge_id' should be a 48-bit MAC address as returned by
203 * eth_addr_to_uint64(). 'bridge_id' may also have a priority value in its top
204 * 16 bits; if those bits are set to 0, STP_DEFAULT_BRIDGE_PRIORITY is used.
205 * (This priority may be changed with stp_set_bridge_priority().)
207 * When the bridge needs to send out a BPDU, it calls 'send_bpdu'. This
208 * callback may be called from stp_tick() or stp_received_bpdu(). The
209 * arguments to 'send_bpdu' are an STP BPDU encapsulated in
212 stp_create(const char *name
, stp_identifier bridge_id
,
213 void (*send_bpdu
)(struct ofpbuf
*bpdu
, int port_no
, void *aux
),
219 stp
= xzalloc(sizeof *stp
);
220 stp
->name
= xstrdup(name
);
221 stp
->bridge_id
= bridge_id
;
222 if (!(stp
->bridge_id
>> 48)) {
223 stp
->bridge_id
|= (uint64_t) STP_DEFAULT_BRIDGE_PRIORITY
<< 48;
226 stp
->rq_max_age
= 6000;
227 stp
->rq_hello_time
= 2000;
228 stp
->rq_forward_delay
= 4000;
229 stp_update_bridge_timers(stp
);
230 stp
->max_age
= stp
->bridge_max_age
;
231 stp
->hello_time
= stp
->bridge_hello_time
;
232 stp
->forward_delay
= stp
->bridge_forward_delay
;
234 stp
->designated_root
= stp
->bridge_id
;
235 stp
->root_path_cost
= 0;
236 stp
->root_port
= NULL
;
237 stp
->topology_change_detected
= false;
238 stp
->topology_change
= false;
240 stp_stop_timer(&stp
->tcn_timer
);
241 stp_stop_timer(&stp
->topology_change_timer
);
242 stp_start_timer(&stp
->hello_timer
, 0);
244 stp
->send_bpdu
= send_bpdu
;
247 stp
->first_changed_port
= &stp
->ports
[ARRAY_SIZE(stp
->ports
)];
248 for (p
= stp
->ports
; p
< &stp
->ports
[ARRAY_SIZE(stp
->ports
)]; p
++) {
250 p
->port_id
= (stp_port_no(p
) + 1) | (STP_DEFAULT_PORT_PRIORITY
<< 8);
251 p
->path_cost
= 19; /* Recommended default for 100 Mb/s link. */
252 stp_initialize_port(p
, STP_DISABLED
);
257 /* Destroys 'stp'. */
259 stp_destroy(struct stp
*stp
)
267 /* Runs 'stp' given that 'ms' milliseconds have passed. */
269 stp_tick(struct stp
*stp
, int ms
)
274 /* Convert 'ms' to STP timer ticks. Preserve any leftover milliseconds
275 * from previous stp_tick() calls so that we don't lose STP ticks when we
276 * are called too frequently. */
277 ms
= clamp(ms
, 0, INT_MAX
- 1000) + stp
->elapsed_remainder
;
278 elapsed
= ms_to_timer(ms
);
279 stp
->elapsed_remainder
= ms_to_timer_remainder(ms
);
284 if (stp_timer_expired(&stp
->hello_timer
, elapsed
, stp
->hello_time
)) {
285 stp_hello_timer_expiry(stp
);
287 if (stp_timer_expired(&stp
->tcn_timer
, elapsed
, stp
->bridge_hello_time
)) {
288 stp_tcn_timer_expiry(stp
);
290 if (stp_timer_expired(&stp
->topology_change_timer
, elapsed
,
291 stp
->max_age
+ stp
->forward_delay
)) {
292 stp_topology_change_timer_expiry(stp
);
294 FOR_EACH_ENABLED_PORT (p
, stp
) {
295 if (stp_timer_expired(&p
->message_age_timer
, elapsed
, stp
->max_age
)) {
296 stp_message_age_timer_expiry(p
);
299 FOR_EACH_ENABLED_PORT (p
, stp
) {
300 if (stp_timer_expired(&p
->forward_delay_timer
, elapsed
,
301 stp
->forward_delay
)) {
302 stp_forward_delay_timer_expiry(p
);
304 if (stp_timer_expired(&p
->hold_timer
, elapsed
, ms_to_timer(1000))) {
305 stp_hold_timer_expiry(p
);
311 set_bridge_id(struct stp
*stp
, stp_identifier new_bridge_id
)
313 if (new_bridge_id
!= stp
->bridge_id
) {
317 root
= stp_is_root_bridge(stp
);
318 FOR_EACH_ENABLED_PORT (p
, stp
) {
319 if (stp_is_designated_port(p
)) {
320 p
->designated_bridge
= new_bridge_id
;
323 stp
->bridge_id
= new_bridge_id
;
324 stp_configuration_update(stp
);
325 stp_port_state_selection(stp
);
326 if (stp_is_root_bridge(stp
) && !root
) {
327 stp_become_root_bridge(stp
);
333 stp_set_bridge_id(struct stp
*stp
, stp_identifier bridge_id
)
335 const uint64_t mac_bits
= (UINT64_C(1) << 48) - 1;
336 const uint64_t pri_bits
= ~mac_bits
;
337 set_bridge_id(stp
, (stp
->bridge_id
& pri_bits
) | (bridge_id
& mac_bits
));
341 stp_set_bridge_priority(struct stp
*stp
, uint16_t new_priority
)
343 const uint64_t mac_bits
= (UINT64_C(1) << 48) - 1;
344 set_bridge_id(stp
, ((stp
->bridge_id
& mac_bits
)
345 | ((uint64_t) new_priority
<< 48)));
348 /* Sets the desired hello time for 'stp' to 'ms', in milliseconds. The actual
349 * hello time is clamped to the range of 1 to 10 seconds and subject to the
350 * relationship (bridge_max_age >= 2 * (bridge_hello_time + 1 s)). The bridge
351 * hello time is only used when 'stp' is the root bridge. */
353 stp_set_hello_time(struct stp
*stp
, int ms
)
355 stp
->rq_hello_time
= ms
;
356 stp_update_bridge_timers(stp
);
359 /* Sets the desired max age for 'stp' to 'ms', in milliseconds. The actual max
360 * age is clamped to the range of 6 to 40 seconds and subject to the
361 * relationships (2 * (bridge_forward_delay - 1 s) >= bridge_max_age) and
362 * (bridge_max_age >= 2 * (bridge_hello_time + 1 s)). The bridge max age is
363 * only used when 'stp' is the root bridge. */
365 stp_set_max_age(struct stp
*stp
, int ms
)
367 stp
->rq_max_age
= ms
;
368 stp_update_bridge_timers(stp
);
371 /* Sets the desired forward delay for 'stp' to 'ms', in milliseconds. The
372 * actual forward delay is clamped to the range of 4 to 30 seconds and subject
373 * to the relationship (2 * (bridge_forward_delay - 1 s) >= bridge_max_age).
374 * The bridge forward delay is only used when 'stp' is the root bridge. */
376 stp_set_forward_delay(struct stp
*stp
, int ms
)
378 stp
->rq_forward_delay
= ms
;
379 stp_update_bridge_timers(stp
);
382 /* Returns the name given to 'stp' in the call to stp_create(). */
384 stp_get_name(const struct stp
*stp
)
389 /* Returns the bridge ID for 'stp'. */
391 stp_get_bridge_id(const struct stp
*stp
)
393 return stp
->bridge_id
;
396 /* Returns the bridge ID of the bridge currently believed to be the root. */
398 stp_get_designated_root(const struct stp
*stp
)
400 return stp
->designated_root
;
403 /* Returns true if 'stp' believes itself to the be root of the spanning tree,
404 * false otherwise. */
406 stp_is_root_bridge(const struct stp
*stp
)
408 return stp
->bridge_id
== stp
->designated_root
;
411 /* Returns the cost of the path from 'stp' to the root of the spanning tree. */
413 stp_get_root_path_cost(const struct stp
*stp
)
415 return stp
->root_path_cost
;
418 /* Returns the bridge hello time, in ms. The returned value is not necessarily
419 * the value passed to stp_set_hello_time(): it is clamped to the valid range
420 * and quantized to the STP timer resolution. */
422 stp_get_hello_time(const struct stp
*stp
)
424 return timer_to_ms(stp
->bridge_hello_time
);
427 /* Returns the bridge max age, in ms. The returned value is not necessarily
428 * the value passed to stp_set_max_age(): it is clamped to the valid range,
429 * quantized to the STP timer resolution, and adjusted to match the constraints
430 * due to the hello time. */
432 stp_get_max_age(const struct stp
*stp
)
434 return timer_to_ms(stp
->bridge_max_age
);
437 /* Returns the bridge forward delay, in ms. The returned value is not
438 * necessarily the value passed to stp_set_forward_delay(): it is clamped to
439 * the valid range, quantized to the STP timer resolution, and adjusted to
440 * match the constraints due to the forward delay. */
442 stp_get_forward_delay(const struct stp
*stp
)
444 return timer_to_ms(stp
->bridge_forward_delay
);
447 /* Returns the port in 'stp' with index 'port_no', which must be between 0 and
450 stp_get_port(struct stp
*stp
, int port_no
)
452 assert(port_no
>= 0 && port_no
< ARRAY_SIZE(stp
->ports
));
453 return &stp
->ports
[port_no
];
456 /* Returns the port connecting 'stp' to the root bridge, or a null pointer if
457 * there is no such port. */
459 stp_get_root_port(struct stp
*stp
)
461 return stp
->root_port
;
464 /* Finds a port whose state has changed. If successful, stores the port whose
465 * state changed in '*portp' and returns true. If no port has changed, stores
466 * NULL in '*portp' and returns false. */
468 stp_get_changed_port(struct stp
*stp
, struct stp_port
**portp
)
470 struct stp_port
*end
= &stp
->ports
[ARRAY_SIZE(stp
->ports
)];
473 for (p
= stp
->first_changed_port
; p
< end
; p
++) {
474 if (p
->state_changed
) {
475 p
->state_changed
= false;
476 stp
->first_changed_port
= p
+ 1;
481 stp
->first_changed_port
= end
;
486 /* Returns the name for the given 'state' (for use in debugging and log
489 stp_state_name(enum stp_state state
)
507 /* Returns true if 'state' is one in which packets received on a port should
508 * be forwarded, false otherwise.
510 * Returns true if 'state' is STP_DISABLED, since presumably in that case the
511 * port should still work, just not have STP applied to it. */
513 stp_forward_in_state(enum stp_state state
)
515 return (state
& (STP_DISABLED
| STP_FORWARDING
)) != 0;
518 /* Returns true if 'state' is one in which MAC learning should be done on
519 * packets received on a port, false otherwise.
521 * Returns true if 'state' is STP_DISABLED, since presumably in that case the
522 * port should still work, just not have STP applied to it. */
524 stp_learn_in_state(enum stp_state state
)
526 return (state
& (STP_DISABLED
| STP_LEARNING
| STP_FORWARDING
)) != 0;
529 /* Notifies the STP entity that bridge protocol data unit 'bpdu', which is
530 * 'bpdu_size' bytes in length, was received on port 'p'.
532 * This function may call the 'send_bpdu' function provided to stp_create(). */
534 stp_received_bpdu(struct stp_port
*p
, const void *bpdu
, size_t bpdu_size
)
536 struct stp
*stp
= p
->stp
;
537 const struct stp_bpdu_header
*header
;
539 if (p
->state
== STP_DISABLED
) {
543 if (bpdu_size
< sizeof(struct stp_bpdu_header
)) {
544 VLOG_WARN("%s: received runt %zu-byte BPDU", stp
->name
, bpdu_size
);
549 if (header
->protocol_id
!= htons(STP_PROTOCOL_ID
)) {
550 VLOG_WARN("%s: received BPDU with unexpected protocol ID %"PRIu16
,
551 stp
->name
, ntohs(header
->protocol_id
));
554 if (header
->protocol_version
!= STP_PROTOCOL_VERSION
) {
555 VLOG_DBG("%s: received BPDU with unexpected protocol version %"PRIu8
,
556 stp
->name
, header
->protocol_version
);
559 switch (header
->bpdu_type
) {
560 case STP_TYPE_CONFIG
:
561 if (bpdu_size
< sizeof(struct stp_config_bpdu
)) {
562 VLOG_WARN("%s: received config BPDU with invalid size %zu",
563 stp
->name
, bpdu_size
);
566 stp_received_config_bpdu(stp
, p
, bpdu
);
570 if (bpdu_size
!= sizeof(struct stp_tcn_bpdu
)) {
571 VLOG_WARN("%s: received TCN BPDU with invalid size %zu",
572 stp
->name
, bpdu_size
);
575 stp_received_tcn_bpdu(stp
, p
);
579 VLOG_WARN("%s: received BPDU of unexpected type %"PRIu8
,
580 stp
->name
, header
->bpdu_type
);
585 /* Returns the STP entity in which 'p' is nested. */
587 stp_port_get_stp(struct stp_port
*p
)
592 /* Returns the index of port 'p' within its bridge. */
594 stp_port_no(const struct stp_port
*p
)
596 struct stp
*stp
= p
->stp
;
597 assert(p
>= stp
->ports
&& p
< &stp
->ports
[ARRAY_SIZE(stp
->ports
)]);
598 return p
- stp
->ports
;
601 /* Returns the state of port 'p'. */
603 stp_port_get_state(const struct stp_port
*p
)
608 /* Disables STP on port 'p'. */
610 stp_port_disable(struct stp_port
*p
)
612 struct stp
*stp
= p
->stp
;
613 if (p
->state
!= STP_DISABLED
) {
614 bool root
= stp_is_root_bridge(stp
);
615 stp_become_designated_port(p
);
616 stp_set_port_state(p
, STP_DISABLED
);
617 p
->topology_change_ack
= false;
618 p
->config_pending
= false;
619 stp_stop_timer(&p
->message_age_timer
);
620 stp_stop_timer(&p
->forward_delay_timer
);
621 stp_configuration_update(stp
);
622 stp_port_state_selection(stp
);
623 if (stp_is_root_bridge(stp
) && !root
) {
624 stp_become_root_bridge(stp
);
629 /* Enables STP on port 'p'. The port will initially be in "blocking" state. */
631 stp_port_enable(struct stp_port
*p
)
633 if (p
->state
== STP_DISABLED
) {
634 stp_initialize_port(p
, STP_BLOCKING
);
635 stp_port_state_selection(p
->stp
);
639 /* Sets the priority of port 'p' to 'new_priority'. Lower numerical values
640 * are interpreted as higher priorities. */
642 stp_port_set_priority(struct stp_port
*p
, uint8_t new_priority
)
644 uint16_t new_port_id
= (p
->port_id
& 0xff) | (new_priority
<< 8);
645 if (p
->port_id
!= new_port_id
) {
646 struct stp
*stp
= p
->stp
;
647 if (stp_is_designated_port(p
)) {
648 p
->designated_port
= new_port_id
;
650 p
->port_id
= new_port_id
;
651 if (stp
->bridge_id
== p
->designated_bridge
652 && p
->port_id
< p
->designated_port
) {
653 stp_become_designated_port(p
);
654 stp_port_state_selection(stp
);
659 /* Sets the path cost of port 'p' to 'path_cost'. Lower values are generally
660 * used to indicate faster links. Use stp_port_set_speed() to automatically
661 * generate a default path cost from a link speed. */
663 stp_port_set_path_cost(struct stp_port
*p
, uint16_t path_cost
)
665 if (p
->path_cost
!= path_cost
) {
666 struct stp
*stp
= p
->stp
;
667 p
->path_cost
= path_cost
;
668 stp_configuration_update(stp
);
669 stp_port_state_selection(stp
);
673 /* Sets the path cost of port 'p' based on 'speed' (measured in Mb/s). */
675 stp_port_set_speed(struct stp_port
*p
, unsigned int speed
)
677 stp_port_set_path_cost(p
, (speed
>= 10000 ? 2 /* 10 Gb/s. */
678 : speed
>= 1000 ? 4 /* 1 Gb/s. */
679 : speed
>= 100 ? 19 /* 100 Mb/s. */
680 : speed
>= 16 ? 62 /* 16 Mb/s. */
681 : speed
>= 10 ? 100 /* 10 Mb/s. */
682 : speed
>= 4 ? 250 /* 4 Mb/s. */
683 : 19)); /* 100 Mb/s (guess). */
686 /* Enables topology change detection on port 'p'. */
688 stp_port_enable_change_detection(struct stp_port
*p
)
690 p
->change_detection_enabled
= true;
693 /* Disables topology change detection on port 'p'. */
695 stp_port_disable_change_detection(struct stp_port
*p
)
697 p
->change_detection_enabled
= false;
701 stp_transmit_config(struct stp_port
*p
)
703 struct stp
*stp
= p
->stp
;
704 bool root
= stp_is_root_bridge(stp
);
705 if (!root
&& !stp
->root_port
) {
708 if (p
->hold_timer
.active
) {
709 p
->config_pending
= true;
711 struct stp_config_bpdu config
;
712 memset(&config
, 0, sizeof config
);
713 config
.header
.protocol_id
= htons(STP_PROTOCOL_ID
);
714 config
.header
.protocol_version
= STP_PROTOCOL_VERSION
;
715 config
.header
.bpdu_type
= STP_TYPE_CONFIG
;
717 if (p
->topology_change_ack
) {
718 config
.flags
|= htons(STP_CONFIG_TOPOLOGY_CHANGE_ACK
);
720 if (stp
->topology_change
) {
721 config
.flags
|= htons(STP_CONFIG_TOPOLOGY_CHANGE
);
723 config
.root_id
= htonll(stp
->designated_root
);
724 config
.root_path_cost
= htonl(stp
->root_path_cost
);
725 config
.bridge_id
= htonll(stp
->bridge_id
);
726 config
.port_id
= htons(p
->port_id
);
728 config
.message_age
= htons(0);
730 config
.message_age
= htons(stp
->root_port
->message_age_timer
.value
731 + MESSAGE_AGE_INCREMENT
);
733 config
.max_age
= htons(stp
->max_age
);
734 config
.hello_time
= htons(stp
->hello_time
);
735 config
.forward_delay
= htons(stp
->forward_delay
);
736 if (ntohs(config
.message_age
) < stp
->max_age
) {
737 p
->topology_change_ack
= false;
738 p
->config_pending
= false;
739 stp_send_bpdu(p
, &config
, sizeof config
);
740 stp_start_timer(&p
->hold_timer
, 0);
746 stp_supersedes_port_info(const struct stp_port
*p
,
747 const struct stp_config_bpdu
*config
)
749 if (ntohll(config
->root_id
) != p
->designated_root
) {
750 return ntohll(config
->root_id
) < p
->designated_root
;
751 } else if (ntohl(config
->root_path_cost
) != p
->designated_cost
) {
752 return ntohl(config
->root_path_cost
) < p
->designated_cost
;
753 } else if (ntohll(config
->bridge_id
) != p
->designated_bridge
) {
754 return ntohll(config
->bridge_id
) < p
->designated_bridge
;
756 return (ntohll(config
->bridge_id
) != p
->stp
->bridge_id
757 || ntohs(config
->port_id
) <= p
->designated_port
);
762 stp_record_config_information(struct stp_port
*p
,
763 const struct stp_config_bpdu
*config
)
765 p
->designated_root
= ntohll(config
->root_id
);
766 p
->designated_cost
= ntohl(config
->root_path_cost
);
767 p
->designated_bridge
= ntohll(config
->bridge_id
);
768 p
->designated_port
= ntohs(config
->port_id
);
769 stp_start_timer(&p
->message_age_timer
, ntohs(config
->message_age
));
773 stp_record_config_timeout_values(struct stp
*stp
,
774 const struct stp_config_bpdu
*config
)
776 stp
->max_age
= ntohs(config
->max_age
);
777 stp
->hello_time
= ntohs(config
->hello_time
);
778 stp
->forward_delay
= ntohs(config
->forward_delay
);
779 stp
->topology_change
= config
->flags
& htons(STP_CONFIG_TOPOLOGY_CHANGE
);
783 stp_is_designated_port(const struct stp_port
*p
)
785 return (p
->designated_bridge
== p
->stp
->bridge_id
786 && p
->designated_port
== p
->port_id
);
790 stp_config_bpdu_generation(struct stp
*stp
)
794 FOR_EACH_ENABLED_PORT (p
, stp
) {
795 if (stp_is_designated_port(p
)) {
796 stp_transmit_config(p
);
802 stp_transmit_tcn(struct stp
*stp
)
804 struct stp_port
*p
= stp
->root_port
;
805 struct stp_tcn_bpdu tcn_bpdu
;
809 tcn_bpdu
.header
.protocol_id
= htons(STP_PROTOCOL_ID
);
810 tcn_bpdu
.header
.protocol_version
= STP_PROTOCOL_VERSION
;
811 tcn_bpdu
.header
.bpdu_type
= STP_TYPE_TCN
;
812 stp_send_bpdu(p
, &tcn_bpdu
, sizeof tcn_bpdu
);
816 stp_configuration_update(struct stp
*stp
)
818 stp_root_selection(stp
);
819 stp_designated_port_selection(stp
);
823 stp_supersedes_root(const struct stp_port
*root
, const struct stp_port
*p
)
825 int p_cost
= p
->designated_cost
+ p
->path_cost
;
826 int root_cost
= root
->designated_cost
+ root
->path_cost
;
828 if (p
->designated_root
!= root
->designated_root
) {
829 return p
->designated_root
< root
->designated_root
;
830 } else if (p_cost
!= root_cost
) {
831 return p_cost
< root_cost
;
832 } else if (p
->designated_bridge
!= root
->designated_bridge
) {
833 return p
->designated_bridge
< root
->designated_bridge
;
834 } else if (p
->designated_port
!= root
->designated_port
) {
835 return p
->designated_port
< root
->designated_port
;
837 return p
->port_id
< root
->port_id
;
842 stp_root_selection(struct stp
*stp
)
844 struct stp_port
*p
, *root
;
847 FOR_EACH_ENABLED_PORT (p
, stp
) {
848 if (stp_is_designated_port(p
)
849 || p
->designated_root
>= stp
->bridge_id
) {
852 if (root
&& !stp_supersedes_root(root
, p
)) {
857 stp
->root_port
= root
;
859 stp
->designated_root
= stp
->bridge_id
;
860 stp
->root_path_cost
= 0;
862 stp
->designated_root
= root
->designated_root
;
863 stp
->root_path_cost
= root
->designated_cost
+ root
->path_cost
;
868 stp_designated_port_selection(struct stp
*stp
)
872 FOR_EACH_ENABLED_PORT (p
, stp
) {
873 if (stp_is_designated_port(p
)
874 || p
->designated_root
!= stp
->designated_root
875 || stp
->root_path_cost
< p
->designated_cost
876 || (stp
->root_path_cost
== p
->designated_cost
877 && (stp
->bridge_id
< p
->designated_bridge
878 || (stp
->bridge_id
== p
->designated_bridge
879 && p
->port_id
<= p
->designated_port
))))
881 stp_become_designated_port(p
);
887 stp_become_designated_port(struct stp_port
*p
)
889 struct stp
*stp
= p
->stp
;
890 p
->designated_root
= stp
->designated_root
;
891 p
->designated_cost
= stp
->root_path_cost
;
892 p
->designated_bridge
= stp
->bridge_id
;
893 p
->designated_port
= p
->port_id
;
897 stp_port_state_selection(struct stp
*stp
)
901 FOR_EACH_ENABLED_PORT (p
, stp
) {
902 if (p
== stp
->root_port
) {
903 p
->config_pending
= false;
904 p
->topology_change_ack
= false;
905 stp_make_forwarding(p
);
906 } else if (stp_is_designated_port(p
)) {
907 stp_stop_timer(&p
->message_age_timer
);
908 stp_make_forwarding(p
);
910 p
->config_pending
= false;
911 p
->topology_change_ack
= false;
912 stp_make_blocking(p
);
918 stp_make_forwarding(struct stp_port
*p
)
920 if (p
->state
== STP_BLOCKING
) {
921 stp_set_port_state(p
, STP_LISTENING
);
922 stp_start_timer(&p
->forward_delay_timer
, 0);
927 stp_make_blocking(struct stp_port
*p
)
929 if (!(p
->state
& (STP_DISABLED
| STP_BLOCKING
))) {
930 if (p
->state
& (STP_FORWARDING
| STP_LEARNING
)) {
931 if (p
->change_detection_enabled
) {
932 stp_topology_change_detection(p
->stp
);
935 stp_set_port_state(p
, STP_BLOCKING
);
936 stp_stop_timer(&p
->forward_delay_timer
);
941 stp_set_port_state(struct stp_port
*p
, enum stp_state state
)
943 if (state
!= p
->state
&& !p
->state_changed
) {
944 p
->state_changed
= true;
945 if (p
< p
->stp
->first_changed_port
) {
946 p
->stp
->first_changed_port
= p
;
953 stp_topology_change_detection(struct stp
*stp
)
955 if (stp_is_root_bridge(stp
)) {
956 stp
->topology_change
= true;
957 stp_start_timer(&stp
->topology_change_timer
, 0);
958 } else if (!stp
->topology_change_detected
) {
959 stp_transmit_tcn(stp
);
960 stp_start_timer(&stp
->tcn_timer
, 0);
962 stp
->topology_change_detected
= true;
966 stp_topology_change_acknowledged(struct stp
*stp
)
968 stp
->topology_change_detected
= false;
969 stp_stop_timer(&stp
->tcn_timer
);
973 stp_acknowledge_topology_change(struct stp_port
*p
)
975 p
->topology_change_ack
= true;
976 stp_transmit_config(p
);
980 stp_received_config_bpdu(struct stp
*stp
, struct stp_port
*p
,
981 const struct stp_config_bpdu
*config
)
983 if (ntohs(config
->message_age
) >= ntohs(config
->max_age
)) {
984 VLOG_WARN("%s: received config BPDU with message age (%u) greater "
987 ntohs(config
->message_age
), ntohs(config
->max_age
));
990 if (p
->state
!= STP_DISABLED
) {
991 bool root
= stp_is_root_bridge(stp
);
992 if (stp_supersedes_port_info(p
, config
)) {
993 stp_record_config_information(p
, config
);
994 stp_configuration_update(stp
);
995 stp_port_state_selection(stp
);
996 if (!stp_is_root_bridge(stp
) && root
) {
997 stp_stop_timer(&stp
->hello_timer
);
998 if (stp
->topology_change_detected
) {
999 stp_stop_timer(&stp
->topology_change_timer
);
1000 stp_transmit_tcn(stp
);
1001 stp_start_timer(&stp
->tcn_timer
, 0);
1004 if (p
== stp
->root_port
) {
1005 stp_record_config_timeout_values(stp
, config
);
1006 stp_config_bpdu_generation(stp
);
1007 if (config
->flags
& htons(STP_CONFIG_TOPOLOGY_CHANGE_ACK
)) {
1008 stp_topology_change_acknowledged(stp
);
1011 } else if (stp_is_designated_port(p
)) {
1012 stp_transmit_config(p
);
1018 stp_received_tcn_bpdu(struct stp
*stp
, struct stp_port
*p
)
1020 if (p
->state
!= STP_DISABLED
) {
1021 if (stp_is_designated_port(p
)) {
1022 stp_topology_change_detection(stp
);
1023 stp_acknowledge_topology_change(p
);
1029 stp_hello_timer_expiry(struct stp
*stp
)
1031 stp_config_bpdu_generation(stp
);
1032 stp_start_timer(&stp
->hello_timer
, 0);
1036 stp_message_age_timer_expiry(struct stp_port
*p
)
1038 struct stp
*stp
= p
->stp
;
1039 bool root
= stp_is_root_bridge(stp
);
1040 stp_become_designated_port(p
);
1041 stp_configuration_update(stp
);
1042 stp_port_state_selection(stp
);
1043 if (stp_is_root_bridge(stp
) && !root
) {
1044 stp
->max_age
= stp
->bridge_max_age
;
1045 stp
->hello_time
= stp
->bridge_hello_time
;
1046 stp
->forward_delay
= stp
->bridge_forward_delay
;
1047 stp_topology_change_detection(stp
);
1048 stp_stop_timer(&stp
->tcn_timer
);
1049 stp_config_bpdu_generation(stp
);
1050 stp_start_timer(&stp
->hello_timer
, 0);
1055 stp_is_designated_for_some_port(const struct stp
*stp
)
1057 const struct stp_port
*p
;
1059 FOR_EACH_ENABLED_PORT (p
, stp
) {
1060 if (p
->designated_bridge
== stp
->bridge_id
) {
1068 stp_forward_delay_timer_expiry(struct stp_port
*p
)
1070 if (p
->state
== STP_LISTENING
) {
1071 stp_set_port_state(p
, STP_LEARNING
);
1072 stp_start_timer(&p
->forward_delay_timer
, 0);
1073 } else if (p
->state
== STP_LEARNING
) {
1074 stp_set_port_state(p
, STP_FORWARDING
);
1075 if (stp_is_designated_for_some_port(p
->stp
)) {
1076 if (p
->change_detection_enabled
) {
1077 stp_topology_change_detection(p
->stp
);
1084 stp_tcn_timer_expiry(struct stp
*stp
)
1086 stp_transmit_tcn(stp
);
1087 stp_start_timer(&stp
->tcn_timer
, 0);
1091 stp_topology_change_timer_expiry(struct stp
*stp
)
1093 stp
->topology_change_detected
= false;
1094 stp
->topology_change
= false;
1098 stp_hold_timer_expiry(struct stp_port
*p
)
1100 if (p
->config_pending
) {
1101 stp_transmit_config(p
);
1106 stp_initialize_port(struct stp_port
*p
, enum stp_state state
)
1108 assert(state
& (STP_DISABLED
| STP_BLOCKING
));
1109 stp_become_designated_port(p
);
1110 stp_set_port_state(p
, state
);
1111 p
->topology_change_ack
= false;
1112 p
->config_pending
= false;
1113 p
->change_detection_enabled
= true;
1114 stp_stop_timer(&p
->message_age_timer
);
1115 stp_stop_timer(&p
->forward_delay_timer
);
1116 stp_stop_timer(&p
->hold_timer
);
1120 stp_become_root_bridge(struct stp
*stp
)
1122 stp
->max_age
= stp
->bridge_max_age
;
1123 stp
->hello_time
= stp
->bridge_hello_time
;
1124 stp
->forward_delay
= stp
->bridge_forward_delay
;
1125 stp_topology_change_detection(stp
);
1126 stp_stop_timer(&stp
->tcn_timer
);
1127 stp_config_bpdu_generation(stp
);
1128 stp_start_timer(&stp
->hello_timer
, 0);
1132 stp_start_timer(struct stp_timer
*timer
, int value
)
1134 timer
->value
= value
;
1135 timer
->active
= true;
1139 stp_stop_timer(struct stp_timer
*timer
)
1141 timer
->active
= false;
1145 stp_timer_expired(struct stp_timer
*timer
, int elapsed
, int timeout
)
1147 if (timer
->active
) {
1148 timer
->value
+= elapsed
;
1149 if (timer
->value
>= timeout
) {
1150 timer
->active
= false;
1157 /* Returns the number of whole STP timer ticks in 'ms' milliseconds. There
1158 * are 256 STP timer ticks per second. */
1162 return ms
* 0x100 / 1000;
1165 /* Returns the number of leftover milliseconds when 'ms' is converted to STP
1168 ms_to_timer_remainder(int ms
)
1170 return ms
* 0x100 % 1000;
1173 /* Returns the number of whole milliseconds in 'timer' STP timer ticks. There
1174 * are 256 STP timer ticks per second. */
1176 timer_to_ms(int timer
)
1178 return timer
* 1000 / 0x100;
1182 clamp(int x
, int min
, int max
)
1184 return x
< min
? min
: x
> max
? max
: x
;
1188 stp_update_bridge_timers(struct stp
*stp
)
1192 ht
= clamp(stp
->rq_hello_time
, 1000, 10000);
1193 ma
= clamp(stp
->rq_max_age
, MAX(2 * (ht
+ 1000), 6000), 40000);
1194 fd
= clamp(stp
->rq_forward_delay
, ma
/ 2 + 1000, 30000);
1196 stp
->bridge_hello_time
= ms_to_timer(ht
);
1197 stp
->bridge_max_age
= ms_to_timer(ma
);
1198 stp
->bridge_forward_delay
= ms_to_timer(fd
);
1200 if (stp_is_root_bridge(stp
)) {
1201 stp
->max_age
= stp
->bridge_max_age
;
1202 stp
->hello_time
= stp
->bridge_hello_time
;
1203 stp
->forward_delay
= stp
->bridge_forward_delay
;
1208 stp_send_bpdu(struct stp_port
*p
, const void *bpdu
, size_t bpdu_size
)
1210 struct eth_header
*eth
;
1211 struct llc_header
*llc
;
1215 pkt
= ofpbuf_new(ETH_HEADER_LEN
+ LLC_HEADER_LEN
+ bpdu_size
);
1216 pkt
->l2
= eth
= ofpbuf_put_zeros(pkt
, sizeof *eth
);
1217 llc
= ofpbuf_put_zeros(pkt
, sizeof *llc
);
1218 pkt
->l3
= ofpbuf_put(pkt
, bpdu
, bpdu_size
);
1221 memcpy(eth
->eth_dst
, stp_eth_addr
, ETH_ADDR_LEN
);
1222 /* p->stp->send_bpdu() must fill in source address. */
1223 eth
->eth_type
= htons(pkt
->size
- ETH_HEADER_LEN
);
1226 llc
->llc_dsap
= STP_LLC_DSAP
;
1227 llc
->llc_ssap
= STP_LLC_SSAP
;
1228 llc
->llc_cntl
= STP_LLC_CNTL
;
1230 p
->stp
->send_bpdu(pkt
, stp_port_no(p
), p
->stp
->aux
);