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829a7d02 JP |
1 | /* |
2 | * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks. | |
3 | * | |
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: | |
7 | * | |
8 | * http://www.apache.org/licenses/LICENSE-2.0 | |
9 | * | |
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. | |
15 | */ | |
16 | ||
17 | /* Based on sample implementation in 802.1D-1998. Above copyright and license | |
18 | * applies to all modifications. */ | |
19 | ||
20 | #include <config.h> | |
21 | ||
22 | #include "stp.h" | |
23 | #include <sys/types.h> | |
24 | #include <netinet/in.h> | |
25 | #include <arpa/inet.h> | |
26 | #include <assert.h> | |
27 | #include <inttypes.h> | |
28 | #include <stdlib.h> | |
29 | #include "byte-order.h" | |
30 | #include "ofpbuf.h" | |
31 | #include "packets.h" | |
32 | #include "util.h" | |
33 | #include "vlog.h" | |
34 | ||
35 | VLOG_DEFINE_THIS_MODULE(stp); | |
36 | ||
37 | #define STP_PROTOCOL_ID 0x0000 | |
38 | #define STP_PROTOCOL_VERSION 0x00 | |
39 | #define STP_TYPE_CONFIG 0x00 | |
40 | #define STP_TYPE_TCN 0x80 | |
41 | ||
42 | struct stp_bpdu_header { | |
43 | ovs_be16 protocol_id; /* STP_PROTOCOL_ID. */ | |
44 | uint8_t protocol_version; /* STP_PROTOCOL_VERSION. */ | |
45 | uint8_t bpdu_type; /* One of STP_TYPE_*. */ | |
46 | } __attribute__((packed)); | |
47 | BUILD_ASSERT_DECL(sizeof(struct stp_bpdu_header) == 4); | |
48 | ||
49 | enum stp_config_bpdu_flags { | |
50 | STP_CONFIG_TOPOLOGY_CHANGE_ACK = 0x80, | |
51 | STP_CONFIG_TOPOLOGY_CHANGE = 0x01 | |
52 | }; | |
53 | ||
54 | struct stp_config_bpdu { | |
55 | struct stp_bpdu_header header; /* Type STP_TYPE_CONFIG. */ | |
56 | uint8_t flags; /* STP_CONFIG_* flags. */ | |
57 | ovs_be64 root_id; /* 8.5.1.1: Bridge believed to be root. */ | |
58 | ovs_be32 root_path_cost; /* 8.5.1.2: Cost of path to root. */ | |
59 | ovs_be64 bridge_id; /* 8.5.1.3: ID of transmitting bridge. */ | |
60 | ovs_be16 port_id; /* 8.5.1.4: Port transmitting the BPDU. */ | |
61 | ovs_be16 message_age; /* 8.5.1.5: Age of BPDU at tx time. */ | |
62 | ovs_be16 max_age; /* 8.5.1.6: Timeout for received data. */ | |
63 | ovs_be16 hello_time; /* 8.5.1.7: Time between BPDU generation. */ | |
64 | ovs_be16 forward_delay; /* 8.5.1.8: State progression delay. */ | |
65 | } __attribute__((packed)); | |
66 | BUILD_ASSERT_DECL(sizeof(struct stp_config_bpdu) == 35); | |
67 | ||
68 | struct stp_tcn_bpdu { | |
69 | struct stp_bpdu_header header; /* Type STP_TYPE_TCN. */ | |
70 | } __attribute__((packed)); | |
71 | BUILD_ASSERT_DECL(sizeof(struct stp_tcn_bpdu) == 4); | |
72 | ||
73 | struct stp_timer { | |
74 | bool active; /* Timer in use? */ | |
75 | int value; /* Current value of timer, counting up. */ | |
76 | }; | |
77 | ||
78 | struct stp_port { | |
79 | struct stp *stp; | |
80 | int port_id; /* 8.5.5.1: Unique port identifier. */ | |
81 | enum stp_state state; /* 8.5.5.2: Current state. */ | |
82 | int path_cost; /* 8.5.5.3: Cost of tx/rx on this port. */ | |
83 | stp_identifier designated_root; /* 8.5.5.4. */ | |
84 | int designated_cost; /* 8.5.5.5: Path cost to root on port. */ | |
85 | stp_identifier designated_bridge; /* 8.5.5.6. */ | |
86 | int designated_port; /* 8.5.5.7: Port to send config msgs on. */ | |
87 | bool topology_change_ack; /* 8.5.5.8: Flag for next config BPDU. */ | |
88 | bool config_pending; /* 8.5.5.9: Send BPDU when hold expires? */ | |
89 | bool change_detection_enabled; /* 8.5.5.10: Detect topology changes? */ | |
90 | ||
91 | struct stp_timer message_age_timer; /* 8.5.6.1: Age of received info. */ | |
92 | struct stp_timer forward_delay_timer; /* 8.5.6.2: State change timer. */ | |
93 | struct stp_timer hold_timer; /* 8.5.6.3: BPDU rate limit timer. */ | |
94 | ||
95 | bool state_changed; | |
96 | }; | |
97 | ||
98 | struct stp { | |
99 | /* Static bridge data. */ | |
100 | char *name; /* Human-readable name for log messages. */ | |
101 | stp_identifier bridge_id; /* 8.5.3.7: This bridge. */ | |
102 | int max_age; /* 8.5.3.4: Time to drop received data. */ | |
103 | int hello_time; /* 8.5.3.5: Time between sending BPDUs. */ | |
104 | int forward_delay; /* 8.5.3.6: Delay between state changes. */ | |
105 | int bridge_max_age; /* 8.5.3.8: max_age when we're root. */ | |
106 | int bridge_hello_time; /* 8.5.3.9: hello_time as root. */ | |
107 | int bridge_forward_delay; /* 8.5.3.10: forward_delay as root. */ | |
108 | int rq_max_age; /* User-requested max age, in ms. */ | |
109 | int rq_hello_time; /* User-requested hello time, in ms. */ | |
110 | int rq_forward_delay; /* User-requested forward delay, in ms. */ | |
111 | int elapsed_remainder; /* Left-over msecs from last stp_tick(). */ | |
112 | ||
113 | /* Dynamic bridge data. */ | |
114 | stp_identifier designated_root; /* 8.5.3.1: Bridge believed to be root. */ | |
115 | unsigned int root_path_cost; /* 8.5.3.2: Cost of path to root. */ | |
116 | struct stp_port *root_port; /* 8.5.3.3: Lowest cost port to root. */ | |
117 | bool topology_change_detected; /* 8.5.3.11: Detected a topology change? */ | |
118 | bool topology_change; /* 8.5.3.12: Received topology change? */ | |
119 | ||
120 | /* Bridge timers. */ | |
121 | struct stp_timer hello_timer; /* 8.5.4.1: Hello timer. */ | |
122 | struct stp_timer tcn_timer; /* 8.5.4.2: Topology change timer. */ | |
123 | struct stp_timer topology_change_timer; /* 8.5.4.3. */ | |
124 | ||
125 | /* Ports. */ | |
126 | struct stp_port ports[STP_MAX_PORTS]; | |
127 | ||
128 | /* Interface to client. */ | |
129 | struct stp_port *first_changed_port; | |
130 | void (*send_bpdu)(struct ofpbuf *bpdu, int port_no, void *aux); | |
131 | void *aux; | |
132 | }; | |
133 | ||
134 | #define FOR_EACH_ENABLED_PORT(PORT, STP) \ | |
135 | for ((PORT) = stp_next_enabled_port((STP), (STP)->ports); \ | |
136 | (PORT); \ | |
137 | (PORT) = stp_next_enabled_port((STP), (PORT) + 1)) | |
138 | static struct stp_port * | |
139 | stp_next_enabled_port(const struct stp *stp, const struct stp_port *port) | |
140 | { | |
141 | for (; port < &stp->ports[ARRAY_SIZE(stp->ports)]; port++) { | |
142 | if (port->state != STP_DISABLED) { | |
143 | return (struct stp_port *) port; | |
144 | } | |
145 | } | |
146 | return NULL; | |
147 | } | |
148 | ||
149 | #define MESSAGE_AGE_INCREMENT 1 | |
150 | ||
151 | static void stp_transmit_config(struct stp_port *); | |
152 | static bool stp_supersedes_port_info(const struct stp_port *, | |
153 | const struct stp_config_bpdu *); | |
154 | static void stp_record_config_information(struct stp_port *, | |
155 | const struct stp_config_bpdu *); | |
156 | static void stp_record_config_timeout_values(struct stp *, | |
157 | const struct stp_config_bpdu *); | |
158 | static bool stp_is_designated_port(const struct stp_port *); | |
159 | static void stp_config_bpdu_generation(struct stp *); | |
160 | static void stp_transmit_tcn(struct stp *); | |
161 | static void stp_configuration_update(struct stp *); | |
162 | static bool stp_supersedes_root(const struct stp_port *root, | |
163 | const struct stp_port *); | |
164 | static void stp_root_selection(struct stp *); | |
165 | static void stp_designated_port_selection(struct stp *); | |
166 | static void stp_become_designated_port(struct stp_port *); | |
167 | static void stp_port_state_selection(struct stp *); | |
168 | static void stp_make_forwarding(struct stp_port *); | |
169 | static void stp_make_blocking(struct stp_port *); | |
170 | static void stp_set_port_state(struct stp_port *, enum stp_state); | |
171 | static void stp_topology_change_detection(struct stp *); | |
172 | static void stp_topology_change_acknowledged(struct stp *); | |
173 | static void stp_acknowledge_topology_change(struct stp_port *); | |
174 | static void stp_received_config_bpdu(struct stp *, struct stp_port *, | |
175 | const struct stp_config_bpdu *); | |
176 | static void stp_received_tcn_bpdu(struct stp *, struct stp_port *); | |
177 | static void stp_hello_timer_expiry(struct stp *); | |
178 | static void stp_message_age_timer_expiry(struct stp_port *); | |
179 | static bool stp_is_designated_for_some_port(const struct stp *); | |
180 | static void stp_forward_delay_timer_expiry(struct stp_port *); | |
181 | static void stp_tcn_timer_expiry(struct stp *); | |
182 | static void stp_topology_change_timer_expiry(struct stp *); | |
183 | static void stp_hold_timer_expiry(struct stp_port *); | |
184 | static void stp_initialize_port(struct stp_port *, enum stp_state); | |
185 | static void stp_become_root_bridge(struct stp *); | |
186 | static void stp_update_bridge_timers(struct stp *); | |
187 | ||
188 | static int clamp(int x, int min, int max); | |
189 | static int ms_to_timer(int ms); | |
190 | static int ms_to_timer_remainder(int ms); | |
191 | static int timer_to_ms(int timer); | |
192 | static void stp_start_timer(struct stp_timer *, int value); | |
193 | static void stp_stop_timer(struct stp_timer *); | |
194 | static bool stp_timer_expired(struct stp_timer *, int elapsed, int timeout); | |
195 | ||
196 | static void stp_send_bpdu(struct stp_port *, const void *, size_t); | |
197 | ||
198 | /* Creates and returns a new STP instance that initially has no ports enabled. | |
199 | * | |
200 | * 'bridge_id' should be a 48-bit MAC address as returned by | |
201 | * eth_addr_to_uint64(). 'bridge_id' may also have a priority value in its top | |
202 | * 16 bits; if those bits are set to 0, STP_DEFAULT_BRIDGE_PRIORITY is used. | |
203 | * (This priority may be changed with stp_set_bridge_priority().) | |
204 | * | |
205 | * When the bridge needs to send out a BPDU, it calls 'send_bpdu'. This | |
206 | * callback may be called from stp_tick() or stp_received_bpdu(). The | |
207 | * arguments to 'send_bpdu' are an STP BPDU encapsulated in 'bpdu', | |
208 | * the spanning tree port number 'port_no' that should transmit the | |
209 | * packet, and auxiliary data to be passed to the callback in 'aux'. | |
210 | */ | |
211 | struct stp * | |
212 | stp_create(const char *name, stp_identifier bridge_id, | |
213 | void (*send_bpdu)(struct ofpbuf *bpdu, int port_no, void *aux), | |
214 | void *aux) | |
215 | { | |
216 | struct stp *stp; | |
217 | struct stp_port *p; | |
218 | ||
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; | |
224 | } | |
225 | ||
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; | |
233 | ||
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; | |
239 | ||
240 | stp_stop_timer(&stp->tcn_timer); | |
241 | stp_stop_timer(&stp->topology_change_timer); | |
242 | stp_start_timer(&stp->hello_timer, 0); | |
243 | ||
244 | stp->send_bpdu = send_bpdu; | |
245 | stp->aux = aux; | |
246 | ||
247 | stp->first_changed_port = &stp->ports[ARRAY_SIZE(stp->ports)]; | |
248 | for (p = stp->ports; p < &stp->ports[ARRAY_SIZE(stp->ports)]; p++) { | |
249 | p->stp = stp; | |
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); | |
253 | } | |
254 | return stp; | |
255 | } | |
256 | ||
257 | /* Destroys 'stp'. */ | |
258 | void | |
259 | stp_destroy(struct stp *stp) | |
260 | { | |
261 | if (stp) { | |
262 | free(stp->name); | |
263 | free(stp); | |
264 | } | |
265 | } | |
266 | ||
267 | /* Runs 'stp' given that 'ms' milliseconds have passed. */ | |
268 | void | |
269 | stp_tick(struct stp *stp, int ms) | |
270 | { | |
271 | struct stp_port *p; | |
272 | int elapsed; | |
273 | ||
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); | |
280 | if (!elapsed) { | |
281 | return; | |
282 | } | |
283 | ||
284 | if (stp_timer_expired(&stp->hello_timer, elapsed, stp->hello_time)) { | |
285 | stp_hello_timer_expiry(stp); | |
286 | } | |
287 | if (stp_timer_expired(&stp->tcn_timer, elapsed, stp->bridge_hello_time)) { | |
288 | stp_tcn_timer_expiry(stp); | |
289 | } | |
290 | if (stp_timer_expired(&stp->topology_change_timer, elapsed, | |
291 | stp->max_age + stp->forward_delay)) { | |
292 | stp_topology_change_timer_expiry(stp); | |
293 | } | |
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); | |
297 | } | |
298 | } | |
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); | |
303 | } | |
304 | if (stp_timer_expired(&p->hold_timer, elapsed, ms_to_timer(1000))) { | |
305 | stp_hold_timer_expiry(p); | |
306 | } | |
307 | } | |
308 | } | |
309 | ||
310 | static void | |
311 | set_bridge_id(struct stp *stp, stp_identifier new_bridge_id) | |
312 | { | |
313 | if (new_bridge_id != stp->bridge_id) { | |
314 | bool root; | |
315 | struct stp_port *p; | |
316 | ||
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; | |
321 | } | |
322 | } | |
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); | |
328 | } | |
329 | } | |
330 | } | |
331 | ||
332 | void | |
333 | stp_set_bridge_id(struct stp *stp, stp_identifier bridge_id) | |
334 | { | |
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)); | |
338 | } | |
339 | ||
340 | void | |
341 | stp_set_bridge_priority(struct stp *stp, uint16_t new_priority) | |
342 | { | |
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))); | |
346 | } | |
347 | ||
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. */ | |
352 | void | |
353 | stp_set_hello_time(struct stp *stp, int ms) | |
354 | { | |
355 | stp->rq_hello_time = ms; | |
356 | stp_update_bridge_timers(stp); | |
357 | } | |
358 | ||
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. */ | |
364 | void | |
365 | stp_set_max_age(struct stp *stp, int ms) | |
366 | { | |
367 | stp->rq_max_age = ms; | |
368 | stp_update_bridge_timers(stp); | |
369 | } | |
370 | ||
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. */ | |
375 | void | |
376 | stp_set_forward_delay(struct stp *stp, int ms) | |
377 | { | |
378 | stp->rq_forward_delay = ms; | |
379 | stp_update_bridge_timers(stp); | |
380 | } | |
381 | ||
382 | /* Returns the name given to 'stp' in the call to stp_create(). */ | |
383 | const char * | |
384 | stp_get_name(const struct stp *stp) | |
385 | { | |
386 | return stp->name; | |
387 | } | |
388 | ||
389 | /* Returns the bridge ID for 'stp'. */ | |
390 | stp_identifier | |
391 | stp_get_bridge_id(const struct stp *stp) | |
392 | { | |
393 | return stp->bridge_id; | |
394 | } | |
395 | ||
396 | /* Returns the bridge ID of the bridge currently believed to be the root. */ | |
397 | stp_identifier | |
398 | stp_get_designated_root(const struct stp *stp) | |
399 | { | |
400 | return stp->designated_root; | |
401 | } | |
402 | ||
403 | /* Returns true if 'stp' believes itself to the be root of the spanning tree, | |
404 | * false otherwise. */ | |
405 | bool | |
406 | stp_is_root_bridge(const struct stp *stp) | |
407 | { | |
408 | return stp->bridge_id == stp->designated_root; | |
409 | } | |
410 | ||
411 | /* Returns the cost of the path from 'stp' to the root of the spanning tree. */ | |
412 | int | |
413 | stp_get_root_path_cost(const struct stp *stp) | |
414 | { | |
415 | return stp->root_path_cost; | |
416 | } | |
417 | ||
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. */ | |
421 | int | |
422 | stp_get_hello_time(const struct stp *stp) | |
423 | { | |
424 | return timer_to_ms(stp->bridge_hello_time); | |
425 | } | |
426 | ||
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. */ | |
431 | int | |
432 | stp_get_max_age(const struct stp *stp) | |
433 | { | |
434 | return timer_to_ms(stp->bridge_max_age); | |
435 | } | |
436 | ||
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. */ | |
441 | int | |
442 | stp_get_forward_delay(const struct stp *stp) | |
443 | { | |
444 | return timer_to_ms(stp->bridge_forward_delay); | |
445 | } | |
446 | ||
447 | /* Returns the port in 'stp' with index 'port_no', which must be between 0 and | |
448 | * STP_MAX_PORTS. */ | |
449 | struct stp_port * | |
450 | stp_get_port(struct stp *stp, int port_no) | |
451 | { | |
452 | assert(port_no >= 0 && port_no < ARRAY_SIZE(stp->ports)); | |
453 | return &stp->ports[port_no]; | |
454 | } | |
455 | ||
456 | /* Returns the port connecting 'stp' to the root bridge, or a null pointer if | |
457 | * there is no such port. */ | |
458 | struct stp_port * | |
459 | stp_get_root_port(struct stp *stp) | |
460 | { | |
461 | return stp->root_port; | |
462 | } | |
463 | ||
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. */ | |
467 | bool | |
468 | stp_get_changed_port(struct stp *stp, struct stp_port **portp) | |
469 | { | |
470 | struct stp_port *end = &stp->ports[ARRAY_SIZE(stp->ports)]; | |
471 | struct stp_port *p; | |
472 | ||
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; | |
477 | *portp = p; | |
478 | return true; | |
479 | } | |
480 | } | |
481 | stp->first_changed_port = end; | |
482 | *portp = NULL; | |
483 | return false; | |
484 | } | |
485 | ||
486 | /* Returns the name for the given 'state' (for use in debugging and log | |
487 | * messages). */ | |
488 | const char * | |
489 | stp_state_name(enum stp_state state) | |
490 | { | |
491 | switch (state) { | |
492 | case STP_DISABLED: | |
493 | return "disabled"; | |
494 | case STP_LISTENING: | |
495 | return "listening"; | |
496 | case STP_LEARNING: | |
497 | return "learning"; | |
498 | case STP_FORWARDING: | |
499 | return "forwarding"; | |
500 | case STP_BLOCKING: | |
501 | return "blocking"; | |
502 | default: | |
503 | NOT_REACHED(); | |
504 | } | |
505 | } | |
506 | ||
507 | /* Returns true if 'state' is one in which packets received on a port should | |
508 | * be forwarded, false otherwise. | |
509 | * | |
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. */ | |
512 | bool | |
513 | stp_forward_in_state(enum stp_state state) | |
514 | { | |
515 | return (state & (STP_DISABLED | STP_FORWARDING)) != 0; | |
516 | } | |
517 | ||
518 | /* Returns true if 'state' is one in which MAC learning should be done on | |
519 | * packets received on a port, false otherwise. | |
520 | * | |
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. */ | |
523 | bool | |
524 | stp_learn_in_state(enum stp_state state) | |
525 | { | |
526 | return (state & (STP_DISABLED | STP_LEARNING | STP_FORWARDING)) != 0; | |
527 | } | |
528 | ||
529 | /* Notifies the STP entity that bridge protocol data unit 'bpdu', which is | |
530 | * 'bpdu_size' bytes in length, was received on port 'p'. | |
531 | * | |
532 | * This function may call the 'send_bpdu' function provided to stp_create(). */ | |
533 | void | |
534 | stp_received_bpdu(struct stp_port *p, const void *bpdu, size_t bpdu_size) | |
535 | { | |
536 | struct stp *stp = p->stp; | |
537 | const struct stp_bpdu_header *header; | |
538 | ||
539 | if (p->state == STP_DISABLED) { | |
540 | return; | |
541 | } | |
542 | ||
543 | if (bpdu_size < sizeof(struct stp_bpdu_header)) { | |
544 | VLOG_WARN("%s: received runt %zu-byte BPDU", stp->name, bpdu_size); | |
545 | return; | |
546 | } | |
547 | ||
548 | header = bpdu; | |
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)); | |
552 | return; | |
553 | } | |
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); | |
557 | } | |
558 | ||
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); | |
564 | return; | |
565 | } | |
566 | stp_received_config_bpdu(stp, p, bpdu); | |
567 | break; | |
568 | ||
569 | case STP_TYPE_TCN: | |
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); | |
573 | return; | |
574 | } | |
575 | stp_received_tcn_bpdu(stp, p); | |
576 | break; | |
577 | ||
578 | default: | |
579 | VLOG_WARN("%s: received BPDU of unexpected type %"PRIu8, | |
580 | stp->name, header->bpdu_type); | |
581 | return; | |
582 | } | |
583 | } | |
584 | ||
585 | /* Returns the STP entity in which 'p' is nested. */ | |
586 | struct stp * | |
587 | stp_port_get_stp(struct stp_port *p) | |
588 | { | |
589 | return p->stp; | |
590 | } | |
591 | ||
592 | /* Returns the index of port 'p' within its bridge. */ | |
593 | int | |
594 | stp_port_no(const struct stp_port *p) | |
595 | { | |
596 | struct stp *stp = p->stp; | |
597 | assert(p >= stp->ports && p < &stp->ports[ARRAY_SIZE(stp->ports)]); | |
598 | return p - stp->ports; | |
599 | } | |
600 | ||
601 | /* Returns the state of port 'p'. */ | |
602 | enum stp_state | |
603 | stp_port_get_state(const struct stp_port *p) | |
604 | { | |
605 | return p->state; | |
606 | } | |
607 | ||
608 | /* Disables STP on port 'p'. */ | |
609 | void | |
610 | stp_port_disable(struct stp_port *p) | |
611 | { | |
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); | |
625 | } | |
626 | } | |
627 | } | |
628 | ||
629 | /* Enables STP on port 'p'. The port will initially be in "blocking" state. */ | |
630 | void | |
631 | stp_port_enable(struct stp_port *p) | |
632 | { | |
633 | if (p->state == STP_DISABLED) { | |
634 | stp_initialize_port(p, STP_BLOCKING); | |
635 | stp_port_state_selection(p->stp); | |
636 | } | |
637 | } | |
638 | ||
639 | /* Sets the priority of port 'p' to 'new_priority'. Lower numerical values | |
640 | * are interpreted as higher priorities. */ | |
641 | void | |
642 | stp_port_set_priority(struct stp_port *p, uint8_t new_priority) | |
643 | { | |
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; | |
649 | } | |
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); | |
655 | } | |
656 | } | |
657 | } | |
658 | ||
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. */ | |
662 | void | |
663 | stp_port_set_path_cost(struct stp_port *p, uint16_t path_cost) | |
664 | { | |
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); | |
670 | } | |
671 | } | |
672 | ||
673 | /* Sets the path cost of port 'p' based on 'speed' (measured in Mb/s). */ | |
674 | void | |
675 | stp_port_set_speed(struct stp_port *p, unsigned int speed) | |
676 | { | |
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). */ | |
684 | } | |
685 | ||
686 | /* Enables topology change detection on port 'p'. */ | |
687 | void | |
688 | stp_port_enable_change_detection(struct stp_port *p) | |
689 | { | |
690 | p->change_detection_enabled = true; | |
691 | } | |
692 | ||
693 | /* Disables topology change detection on port 'p'. */ | |
694 | void | |
695 | stp_port_disable_change_detection(struct stp_port *p) | |
696 | { | |
697 | p->change_detection_enabled = false; | |
698 | } | |
699 | \f | |
700 | static void | |
701 | stp_transmit_config(struct stp_port *p) | |
702 | { | |
703 | struct stp *stp = p->stp; | |
704 | bool root = stp_is_root_bridge(stp); | |
705 | if (!root && !stp->root_port) { | |
706 | return; | |
707 | } | |
708 | if (p->hold_timer.active) { | |
709 | p->config_pending = true; | |
710 | } else { | |
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; | |
716 | config.flags = 0; | |
717 | if (p->topology_change_ack) { | |
718 | config.flags |= htons(STP_CONFIG_TOPOLOGY_CHANGE_ACK); | |
719 | } | |
720 | if (stp->topology_change) { | |
721 | config.flags |= htons(STP_CONFIG_TOPOLOGY_CHANGE); | |
722 | } | |
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); | |
727 | if (root) { | |
728 | config.message_age = htons(0); | |
729 | } else { | |
730 | config.message_age = htons(stp->root_port->message_age_timer.value | |
731 | + MESSAGE_AGE_INCREMENT); | |
732 | } | |
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); | |
741 | } | |
742 | } | |
743 | } | |
744 | ||
745 | static bool | |
746 | stp_supersedes_port_info(const struct stp_port *p, | |
747 | const struct stp_config_bpdu *config) | |
748 | { | |
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; | |
755 | } else { | |
756 | return (ntohll(config->bridge_id) != p->stp->bridge_id | |
757 | || ntohs(config->port_id) <= p->designated_port); | |
758 | } | |
759 | } | |
760 | ||
761 | static void | |
762 | stp_record_config_information(struct stp_port *p, | |
763 | const struct stp_config_bpdu *config) | |
764 | { | |
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)); | |
770 | } | |
771 | ||
772 | static void | |
773 | stp_record_config_timeout_values(struct stp *stp, | |
774 | const struct stp_config_bpdu *config) | |
775 | { | |
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); | |
780 | } | |
781 | ||
782 | static bool | |
783 | stp_is_designated_port(const struct stp_port *p) | |
784 | { | |
785 | return (p->designated_bridge == p->stp->bridge_id | |
786 | && p->designated_port == p->port_id); | |
787 | } | |
788 | ||
789 | static void | |
790 | stp_config_bpdu_generation(struct stp *stp) | |
791 | { | |
792 | struct stp_port *p; | |
793 | ||
794 | FOR_EACH_ENABLED_PORT (p, stp) { | |
795 | if (stp_is_designated_port(p)) { | |
796 | stp_transmit_config(p); | |
797 | } | |
798 | } | |
799 | } | |
800 | ||
801 | static void | |
802 | stp_transmit_tcn(struct stp *stp) | |
803 | { | |
804 | struct stp_port *p = stp->root_port; | |
805 | struct stp_tcn_bpdu tcn_bpdu; | |
806 | if (!p) { | |
807 | return; | |
808 | } | |
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); | |
813 | } | |
814 | ||
815 | static void | |
816 | stp_configuration_update(struct stp *stp) | |
817 | { | |
818 | stp_root_selection(stp); | |
819 | stp_designated_port_selection(stp); | |
820 | } | |
821 | ||
822 | static bool | |
823 | stp_supersedes_root(const struct stp_port *root, const struct stp_port *p) | |
824 | { | |
825 | int p_cost = p->designated_cost + p->path_cost; | |
826 | int root_cost = root->designated_cost + root->path_cost; | |
827 | ||
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; | |
836 | } else { | |
837 | return p->port_id < root->port_id; | |
838 | } | |
839 | } | |
840 | ||
841 | static void | |
842 | stp_root_selection(struct stp *stp) | |
843 | { | |
844 | struct stp_port *p, *root; | |
845 | ||
846 | root = NULL; | |
847 | FOR_EACH_ENABLED_PORT (p, stp) { | |
848 | if (stp_is_designated_port(p) | |
849 | || p->designated_root >= stp->bridge_id) { | |
850 | continue; | |
851 | } | |
852 | if (root && !stp_supersedes_root(root, p)) { | |
853 | continue; | |
854 | } | |
855 | root = p; | |
856 | } | |
857 | stp->root_port = root; | |
858 | if (!root) { | |
859 | stp->designated_root = stp->bridge_id; | |
860 | stp->root_path_cost = 0; | |
861 | } else { | |
862 | stp->designated_root = root->designated_root; | |
863 | stp->root_path_cost = root->designated_cost + root->path_cost; | |
864 | } | |
865 | } | |
866 | ||
867 | static void | |
868 | stp_designated_port_selection(struct stp *stp) | |
869 | { | |
870 | struct stp_port *p; | |
871 | ||
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)))) | |
880 | { | |
881 | stp_become_designated_port(p); | |
882 | } | |
883 | } | |
884 | } | |
885 | ||
886 | static void | |
887 | stp_become_designated_port(struct stp_port *p) | |
888 | { | |
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; | |
894 | } | |
895 | ||
896 | static void | |
897 | stp_port_state_selection(struct stp *stp) | |
898 | { | |
899 | struct stp_port *p; | |
900 | ||
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); | |
909 | } else { | |
910 | p->config_pending = false; | |
911 | p->topology_change_ack = false; | |
912 | stp_make_blocking(p); | |
913 | } | |
914 | } | |
915 | } | |
916 | ||
917 | static void | |
918 | stp_make_forwarding(struct stp_port *p) | |
919 | { | |
920 | if (p->state == STP_BLOCKING) { | |
921 | stp_set_port_state(p, STP_LISTENING); | |
922 | stp_start_timer(&p->forward_delay_timer, 0); | |
923 | } | |
924 | } | |
925 | ||
926 | static void | |
927 | stp_make_blocking(struct stp_port *p) | |
928 | { | |
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); | |
933 | } | |
934 | } | |
935 | stp_set_port_state(p, STP_BLOCKING); | |
936 | stp_stop_timer(&p->forward_delay_timer); | |
937 | } | |
938 | } | |
939 | ||
940 | static void | |
941 | stp_set_port_state(struct stp_port *p, enum stp_state state) | |
942 | { | |
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; | |
947 | } | |
948 | } | |
949 | p->state = state; | |
950 | } | |
951 | ||
952 | static void | |
953 | stp_topology_change_detection(struct stp *stp) | |
954 | { | |
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); | |
961 | } | |
962 | stp->topology_change_detected = true; | |
963 | } | |
964 | ||
965 | static void | |
966 | stp_topology_change_acknowledged(struct stp *stp) | |
967 | { | |
968 | stp->topology_change_detected = false; | |
969 | stp_stop_timer(&stp->tcn_timer); | |
970 | } | |
971 | ||
972 | static void | |
973 | stp_acknowledge_topology_change(struct stp_port *p) | |
974 | { | |
975 | p->topology_change_ack = true; | |
976 | stp_transmit_config(p); | |
977 | } | |
978 | ||
979 | static void | |
980 | stp_received_config_bpdu(struct stp *stp, struct stp_port *p, | |
981 | const struct stp_config_bpdu *config) | |
982 | { | |
983 | if (ntohs(config->message_age) >= ntohs(config->max_age)) { | |
984 | VLOG_WARN("%s: received config BPDU with message age (%u) greater " | |
985 | "than max age (%u)", | |
986 | stp->name, | |
987 | ntohs(config->message_age), ntohs(config->max_age)); | |
988 | return; | |
989 | } | |
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); | |
1002 | } | |
1003 | } | |
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); | |
1009 | } | |
1010 | } | |
1011 | } else if (stp_is_designated_port(p)) { | |
1012 | stp_transmit_config(p); | |
1013 | } | |
1014 | } | |
1015 | } | |
1016 | ||
1017 | static void | |
1018 | stp_received_tcn_bpdu(struct stp *stp, struct stp_port *p) | |
1019 | { | |
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); | |
1024 | } | |
1025 | } | |
1026 | } | |
1027 | ||
1028 | static void | |
1029 | stp_hello_timer_expiry(struct stp *stp) | |
1030 | { | |
1031 | stp_config_bpdu_generation(stp); | |
1032 | stp_start_timer(&stp->hello_timer, 0); | |
1033 | } | |
1034 | ||
1035 | static void | |
1036 | stp_message_age_timer_expiry(struct stp_port *p) | |
1037 | { | |
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); | |
1051 | } | |
1052 | } | |
1053 | ||
1054 | static bool | |
1055 | stp_is_designated_for_some_port(const struct stp *stp) | |
1056 | { | |
1057 | const struct stp_port *p; | |
1058 | ||
1059 | FOR_EACH_ENABLED_PORT (p, stp) { | |
1060 | if (p->designated_bridge == stp->bridge_id) { | |
1061 | return true; | |
1062 | } | |
1063 | } | |
1064 | return false; | |
1065 | } | |
1066 | ||
1067 | static void | |
1068 | stp_forward_delay_timer_expiry(struct stp_port *p) | |
1069 | { | |
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); | |
1078 | } | |
1079 | } | |
1080 | } | |
1081 | } | |
1082 | ||
1083 | static void | |
1084 | stp_tcn_timer_expiry(struct stp *stp) | |
1085 | { | |
1086 | stp_transmit_tcn(stp); | |
1087 | stp_start_timer(&stp->tcn_timer, 0); | |
1088 | } | |
1089 | ||
1090 | static void | |
1091 | stp_topology_change_timer_expiry(struct stp *stp) | |
1092 | { | |
1093 | stp->topology_change_detected = false; | |
1094 | stp->topology_change = false; | |
1095 | } | |
1096 | ||
1097 | static void | |
1098 | stp_hold_timer_expiry(struct stp_port *p) | |
1099 | { | |
1100 | if (p->config_pending) { | |
1101 | stp_transmit_config(p); | |
1102 | } | |
1103 | } | |
1104 | ||
1105 | static void | |
1106 | stp_initialize_port(struct stp_port *p, enum stp_state state) | |
1107 | { | |
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); | |
1117 | } | |
1118 | ||
1119 | static void | |
1120 | stp_become_root_bridge(struct stp *stp) | |
1121 | { | |
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); | |
1129 | } | |
1130 | ||
1131 | static void | |
1132 | stp_start_timer(struct stp_timer *timer, int value) | |
1133 | { | |
1134 | timer->value = value; | |
1135 | timer->active = true; | |
1136 | } | |
1137 | ||
1138 | static void | |
1139 | stp_stop_timer(struct stp_timer *timer) | |
1140 | { | |
1141 | timer->active = false; | |
1142 | } | |
1143 | ||
1144 | static bool | |
1145 | stp_timer_expired(struct stp_timer *timer, int elapsed, int timeout) | |
1146 | { | |
1147 | if (timer->active) { | |
1148 | timer->value += elapsed; | |
1149 | if (timer->value >= timeout) { | |
1150 | timer->active = false; | |
1151 | return true; | |
1152 | } | |
1153 | } | |
1154 | return false; | |
1155 | } | |
1156 | ||
1157 | /* Returns the number of whole STP timer ticks in 'ms' milliseconds. There | |
1158 | * are 256 STP timer ticks per second. */ | |
1159 | static int | |
1160 | ms_to_timer(int ms) | |
1161 | { | |
1162 | return ms * 0x100 / 1000; | |
1163 | } | |
1164 | ||
1165 | /* Returns the number of leftover milliseconds when 'ms' is converted to STP | |
1166 | * timer ticks. */ | |
1167 | static int | |
1168 | ms_to_timer_remainder(int ms) | |
1169 | { | |
1170 | return ms * 0x100 % 1000; | |
1171 | } | |
1172 | ||
1173 | /* Returns the number of whole milliseconds in 'timer' STP timer ticks. There | |
1174 | * are 256 STP timer ticks per second. */ | |
1175 | static int | |
1176 | timer_to_ms(int timer) | |
1177 | { | |
1178 | return timer * 1000 / 0x100; | |
1179 | } | |
1180 | ||
1181 | static int | |
1182 | clamp(int x, int min, int max) | |
1183 | { | |
1184 | return x < min ? min : x > max ? max : x; | |
1185 | } | |
1186 | ||
1187 | static void | |
1188 | stp_update_bridge_timers(struct stp *stp) | |
1189 | { | |
1190 | int ht, ma, fd; | |
1191 | ||
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); | |
1195 | ||
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); | |
1199 | ||
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; | |
1204 | } | |
1205 | } | |
1206 | ||
1207 | static void | |
1208 | stp_send_bpdu(struct stp_port *p, const void *bpdu, size_t bpdu_size) | |
1209 | { | |
1210 | struct eth_header *eth; | |
1211 | struct llc_header *llc; | |
1212 | struct ofpbuf *pkt; | |
1213 | ||
1214 | /* Skeleton. */ | |
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); | |
1219 | ||
1220 | /* 802.2 header. */ | |
1221 | memcpy(eth->eth_dst, eth_addr_stp, ETH_ADDR_LEN); | |
1222 | /* p->stp->send_bpdu() must fill in source address. */ | |
1223 | eth->eth_type = htons(pkt->size - ETH_HEADER_LEN); | |
1224 | ||
1225 | /* LLC header. */ | |
1226 | llc->llc_dsap = STP_LLC_DSAP; | |
1227 | llc->llc_ssap = STP_LLC_SSAP; | |
1228 | llc->llc_cntl = STP_LLC_CNTL; | |
1229 | ||
1230 | p->stp->send_bpdu(pkt, stp_port_no(p), p->stp->aux); | |
1231 | } |