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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * This is an implementation of the IETF SPF delay algorithm | |
4 | * as explained in draft-ietf-rtgwg-backoff-algo-04 | |
5 | * | |
6 | * Created: 25-01-2017 by S. Litkowski | |
7 | * | |
8 | * Copyright (C) 2017 Orange Labs http://www.orange.com/ | |
9 | * Copyright (C) 2017 by Christian Franke, Open Source Routing / NetDEF Inc. | |
10 | * | |
11 | * This file is part of FRRouting (FRR) | |
12 | */ | |
13 | ||
14 | #include <zebra.h> | |
15 | ||
16 | #include "spf_backoff.h" | |
17 | ||
18 | #include "command.h" | |
19 | #include "memory.h" | |
20 | #include "event.h" | |
21 | #include "vty.h" | |
22 | ||
23 | DEFINE_MTYPE_STATIC(LIB, SPF_BACKOFF, "SPF backoff"); | |
24 | DEFINE_MTYPE_STATIC(LIB, SPF_BACKOFF_NAME, "SPF backoff name"); | |
25 | ||
26 | static bool debug_spf_backoff = false; | |
27 | #define backoff_debug(...) \ | |
28 | do { \ | |
29 | if (debug_spf_backoff) \ | |
30 | zlog_debug(__VA_ARGS__); \ | |
31 | } while (0) | |
32 | ||
33 | enum spf_backoff_state { | |
34 | SPF_BACKOFF_QUIET, | |
35 | SPF_BACKOFF_SHORT_WAIT, | |
36 | SPF_BACKOFF_LONG_WAIT | |
37 | }; | |
38 | ||
39 | struct spf_backoff { | |
40 | struct thread_master *m; | |
41 | ||
42 | /* Timers as per draft */ | |
43 | long init_delay; | |
44 | long short_delay; | |
45 | long long_delay; | |
46 | long holddown; | |
47 | long timetolearn; | |
48 | ||
49 | /* State machine */ | |
50 | enum spf_backoff_state state; | |
51 | struct event *t_holddown; | |
52 | struct event *t_timetolearn; | |
53 | ||
54 | /* For debugging */ | |
55 | char *name; | |
56 | struct timeval first_event_time; | |
57 | struct timeval last_event_time; | |
58 | }; | |
59 | ||
60 | static const char *spf_backoff_state2str(enum spf_backoff_state state) | |
61 | { | |
62 | switch (state) { | |
63 | case SPF_BACKOFF_QUIET: | |
64 | return "QUIET"; | |
65 | case SPF_BACKOFF_SHORT_WAIT: | |
66 | return "SHORT_WAIT"; | |
67 | case SPF_BACKOFF_LONG_WAIT: | |
68 | return "LONG_WAIT"; | |
69 | } | |
70 | return "???"; | |
71 | } | |
72 | ||
73 | struct spf_backoff *spf_backoff_new(struct thread_master *m, const char *name, | |
74 | long init_delay, long short_delay, | |
75 | long long_delay, long holddown, | |
76 | long timetolearn) | |
77 | { | |
78 | struct spf_backoff *rv; | |
79 | ||
80 | rv = XCALLOC(MTYPE_SPF_BACKOFF, sizeof(*rv)); | |
81 | rv->m = m; | |
82 | ||
83 | rv->init_delay = init_delay; | |
84 | rv->short_delay = short_delay; | |
85 | rv->long_delay = long_delay; | |
86 | rv->holddown = holddown; | |
87 | rv->timetolearn = timetolearn; | |
88 | ||
89 | rv->state = SPF_BACKOFF_QUIET; | |
90 | ||
91 | rv->name = XSTRDUP(MTYPE_SPF_BACKOFF_NAME, name); | |
92 | return rv; | |
93 | } | |
94 | ||
95 | void spf_backoff_free(struct spf_backoff *backoff) | |
96 | { | |
97 | if (!backoff) | |
98 | return; | |
99 | ||
100 | event_cancel(&backoff->t_holddown); | |
101 | event_cancel(&backoff->t_timetolearn); | |
102 | XFREE(MTYPE_SPF_BACKOFF_NAME, backoff->name); | |
103 | ||
104 | XFREE(MTYPE_SPF_BACKOFF, backoff); | |
105 | } | |
106 | ||
107 | static void spf_backoff_timetolearn_elapsed(struct event *thread) | |
108 | { | |
109 | struct spf_backoff *backoff = THREAD_ARG(thread); | |
110 | ||
111 | backoff->state = SPF_BACKOFF_LONG_WAIT; | |
112 | backoff_debug("SPF Back-off(%s) TIMETOLEARN elapsed, move to state %s", | |
113 | backoff->name, spf_backoff_state2str(backoff->state)); | |
114 | } | |
115 | ||
116 | static void spf_backoff_holddown_elapsed(struct event *thread) | |
117 | { | |
118 | struct spf_backoff *backoff = THREAD_ARG(thread); | |
119 | ||
120 | THREAD_OFF(backoff->t_timetolearn); | |
121 | timerclear(&backoff->first_event_time); | |
122 | backoff->state = SPF_BACKOFF_QUIET; | |
123 | backoff_debug("SPF Back-off(%s) HOLDDOWN elapsed, move to state %s", | |
124 | backoff->name, spf_backoff_state2str(backoff->state)); | |
125 | } | |
126 | ||
127 | long spf_backoff_schedule(struct spf_backoff *backoff) | |
128 | { | |
129 | long rv = 0; | |
130 | struct timeval now; | |
131 | ||
132 | gettimeofday(&now, NULL); | |
133 | ||
134 | backoff_debug("SPF Back-off(%s) schedule called in state %s", | |
135 | backoff->name, spf_backoff_state2str(backoff->state)); | |
136 | ||
137 | backoff->last_event_time = now; | |
138 | ||
139 | switch (backoff->state) { | |
140 | case SPF_BACKOFF_QUIET: | |
141 | backoff->state = SPF_BACKOFF_SHORT_WAIT; | |
142 | event_add_timer_msec( | |
143 | backoff->m, spf_backoff_timetolearn_elapsed, backoff, | |
144 | backoff->timetolearn, &backoff->t_timetolearn); | |
145 | event_add_timer_msec(backoff->m, spf_backoff_holddown_elapsed, | |
146 | backoff, backoff->holddown, | |
147 | &backoff->t_holddown); | |
148 | backoff->first_event_time = now; | |
149 | rv = backoff->init_delay; | |
150 | break; | |
151 | case SPF_BACKOFF_SHORT_WAIT: | |
152 | case SPF_BACKOFF_LONG_WAIT: | |
153 | event_cancel(&backoff->t_holddown); | |
154 | event_add_timer_msec(backoff->m, spf_backoff_holddown_elapsed, | |
155 | backoff, backoff->holddown, | |
156 | &backoff->t_holddown); | |
157 | if (backoff->state == SPF_BACKOFF_SHORT_WAIT) | |
158 | rv = backoff->short_delay; | |
159 | else | |
160 | rv = backoff->long_delay; | |
161 | break; | |
162 | } | |
163 | ||
164 | backoff_debug( | |
165 | "SPF Back-off(%s) changed state to %s and returned %ld delay", | |
166 | backoff->name, spf_backoff_state2str(backoff->state), rv); | |
167 | return rv; | |
168 | } | |
169 | ||
170 | static const char *timeval_format(struct timeval *tv) | |
171 | { | |
172 | struct tm tm_store; | |
173 | struct tm *tm; | |
174 | static char timebuf[256]; | |
175 | ||
176 | if (!tv->tv_sec && !tv->tv_usec) | |
177 | return "(never)"; | |
178 | ||
179 | tm = localtime_r(&tv->tv_sec, &tm_store); | |
180 | if (!tm | |
181 | || strftime(timebuf, sizeof(timebuf), "%Z %a %Y-%m-%d %H:%M:%S", tm) | |
182 | == 0) { | |
183 | return "???"; | |
184 | } | |
185 | ||
186 | size_t offset = strlen(timebuf); | |
187 | snprintf(timebuf + offset, sizeof(timebuf) - offset, ".%ld", | |
188 | (long int)tv->tv_usec); | |
189 | ||
190 | return timebuf; | |
191 | } | |
192 | ||
193 | void spf_backoff_show(struct spf_backoff *backoff, struct vty *vty, | |
194 | const char *prefix) | |
195 | { | |
196 | vty_out(vty, "%sCurrent state: %s\n", prefix, | |
197 | spf_backoff_state2str(backoff->state)); | |
198 | vty_out(vty, "%sInit timer: %ld msec\n", prefix, | |
199 | backoff->init_delay); | |
200 | vty_out(vty, "%sShort timer: %ld msec\n", prefix, | |
201 | backoff->short_delay); | |
202 | vty_out(vty, "%sLong timer: %ld msec\n", prefix, | |
203 | backoff->long_delay); | |
204 | vty_out(vty, "%sHolddown timer: %ld msec\n", prefix, | |
205 | backoff->holddown); | |
206 | if (backoff->t_holddown) { | |
207 | struct timeval remain = | |
208 | thread_timer_remain(backoff->t_holddown); | |
209 | vty_out(vty, "%s Still runs for %lld msec\n", | |
210 | prefix, | |
211 | (long long)remain.tv_sec * 1000 | |
212 | + remain.tv_usec / 1000); | |
213 | } else { | |
214 | vty_out(vty, "%s Inactive\n", prefix); | |
215 | } | |
216 | ||
217 | vty_out(vty, "%sTimeToLearn timer: %ld msec\n", prefix, | |
218 | backoff->timetolearn); | |
219 | if (backoff->t_timetolearn) { | |
220 | struct timeval remain = | |
221 | thread_timer_remain(backoff->t_timetolearn); | |
222 | vty_out(vty, "%s Still runs for %lld msec\n", | |
223 | prefix, | |
224 | (long long)remain.tv_sec * 1000 | |
225 | + remain.tv_usec / 1000); | |
226 | } else { | |
227 | vty_out(vty, "%s Inactive\n", prefix); | |
228 | } | |
229 | ||
230 | vty_out(vty, "%sFirst event: %s\n", prefix, | |
231 | timeval_format(&backoff->first_event_time)); | |
232 | vty_out(vty, "%sLast event: %s\n", prefix, | |
233 | timeval_format(&backoff->last_event_time)); | |
234 | } | |
235 | ||
236 | DEFUN(spf_backoff_debug, | |
237 | spf_backoff_debug_cmd, | |
238 | "debug spf-delay-ietf", | |
239 | DEBUG_STR | |
240 | "SPF Back-off Debugging\n") | |
241 | { | |
242 | debug_spf_backoff = true; | |
243 | return CMD_SUCCESS; | |
244 | } | |
245 | ||
246 | DEFUN(no_spf_backoff_debug, | |
247 | no_spf_backoff_debug_cmd, | |
248 | "no debug spf-delay-ietf", | |
249 | NO_STR | |
250 | DEBUG_STR | |
251 | "SPF Back-off Debugging\n") | |
252 | { | |
253 | debug_spf_backoff = false; | |
254 | return CMD_SUCCESS; | |
255 | } | |
256 | ||
257 | int spf_backoff_write_config(struct vty *vty) | |
258 | { | |
259 | int written = 0; | |
260 | ||
261 | if (debug_spf_backoff) { | |
262 | vty_out(vty, "debug spf-delay-ietf\n"); | |
263 | written++; | |
264 | } | |
265 | ||
266 | return written; | |
267 | } | |
268 | ||
269 | void spf_backoff_cmd_init(void) | |
270 | { | |
271 | install_element(ENABLE_NODE, &spf_backoff_debug_cmd); | |
272 | install_element(CONFIG_NODE, &spf_backoff_debug_cmd); | |
273 | install_element(ENABLE_NODE, &no_spf_backoff_debug_cmd); | |
274 | install_element(CONFIG_NODE, &no_spf_backoff_debug_cmd); | |
275 | } | |
276 | ||
277 | long spf_backoff_init_delay(struct spf_backoff *backoff) | |
278 | { | |
279 | return backoff->init_delay; | |
280 | } | |
281 | ||
282 | long spf_backoff_short_delay(struct spf_backoff *backoff) | |
283 | { | |
284 | return backoff->short_delay; | |
285 | } | |
286 | ||
287 | long spf_backoff_long_delay(struct spf_backoff *backoff) | |
288 | { | |
289 | return backoff->long_delay; | |
290 | } | |
291 | ||
292 | long spf_backoff_holddown(struct spf_backoff *backoff) | |
293 | { | |
294 | return backoff->holddown; | |
295 | } | |
296 | ||
297 | long spf_backoff_timetolearn(struct spf_backoff *backoff) | |
298 | { | |
299 | return backoff->timetolearn; | |
300 | } |