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3 (C) 2010, 2013 Christian Grothoff (and other contributing authors)
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22 * @file util/bandwidth.c
23 * @brief functions related to bandwidth (unit)
24 * @author Christian Grothoff
27 #include "gnunet_util_lib.h"
30 #define LOG(kind,...) GNUNET_log_from (kind, "util-bandwidth", __VA_ARGS__)
33 * Create a new bandwidth value.
35 * @param bytes_per_second value to create
36 * @return the new bandwidth value
38 struct GNUNET_BANDWIDTH_Value32NBO
39 GNUNET_BANDWIDTH_value_init (uint32_t bytes_per_second)
41 struct GNUNET_BANDWIDTH_Value32NBO ret;
43 LOG (GNUNET_ERROR_TYPE_DEBUG,
44 "Initializing bandwidth of %u Bps\n",
45 (unsigned int) bytes_per_second);
46 ret.value__ = htonl (bytes_per_second);
52 * Compute the MIN of two bandwidth values.
54 * @param b1 first value
55 * @param b2 second value
56 * @return the min of b1 and b2
58 struct GNUNET_BANDWIDTH_Value32NBO
59 GNUNET_BANDWIDTH_value_min (struct GNUNET_BANDWIDTH_Value32NBO b1,
60 struct GNUNET_BANDWIDTH_Value32NBO b2)
63 GNUNET_BANDWIDTH_value_init (GNUNET_MIN
64 (ntohl (b1.value__), ntohl (b2.value__)));
69 * At the given bandwidth, calculate how much traffic will be
70 * available until the given deadline.
72 * @param bps bandwidth
73 * @param deadline when is the deadline
74 * @return number of bytes available at bps until deadline
77 GNUNET_BANDWIDTH_value_get_available_until (struct GNUNET_BANDWIDTH_Value32NBO bps,
78 struct GNUNET_TIME_Relative deadline)
82 b = ntohl (bps.value__);
83 LOG (GNUNET_ERROR_TYPE_DEBUG,
84 "Bandwidth has %llu bytes available until deadline in %s\n",
85 (unsigned long long) ((b * deadline.rel_value_us + 500000LL) / 1000000LL),
86 GNUNET_STRINGS_relative_time_to_string (deadline, GNUNET_YES));
87 return (b * deadline.rel_value_us + 500000LL) / 1000000LL;
92 * At the given bandwidth, calculate how long it would take for
93 * @a size bytes to be transmitted.
95 * @param bps bandwidth
96 * @param size number of bytes we want to have available
97 * @return how long it would take
99 struct GNUNET_TIME_Relative
100 GNUNET_BANDWIDTH_value_get_delay_for (struct GNUNET_BANDWIDTH_Value32NBO bps,
104 struct GNUNET_TIME_Relative ret;
106 b = ntohl (bps.value__);
109 LOG (GNUNET_ERROR_TYPE_DEBUG,
110 "Bandwidth suggests delay of infinity (zero bandwidth)\n");
111 return GNUNET_TIME_UNIT_FOREVER_REL;
113 ret.rel_value_us = size * 1000LL * 1000LL / b;
114 LOG (GNUNET_ERROR_TYPE_DEBUG,
115 "Bandwidth suggests delay of %s for %llu bytes of traffic\n",
116 GNUNET_STRINGS_relative_time_to_string (ret, GNUNET_YES),
117 (unsigned long long) size);
123 * Task run whenever we hit the bandwidth limit for a tracker.
125 * @param cls the `struct GNUNET_BANDWIDTH_Tracker`
126 * @param tc scheduler context
129 excess_trigger (void *cls,
130 const struct GNUNET_SCHEDULER_TaskContext *tc)
132 struct GNUNET_BANDWIDTH_Tracker *av = cls;
134 av->excess_task = GNUNET_SCHEDULER_NO_TASK;
136 if (NULL != av->excess_cb)
137 av->excess_cb (av->excess_cb_cls);
142 * Recalculate when we might need to call the excess callback.
145 update_excess (struct GNUNET_BANDWIDTH_Tracker *av)
147 struct GNUNET_TIME_Relative delay;
148 struct GNUNET_TIME_Absolute now;
150 uint64_t delta_avail;
153 int64_t current_consumption;
155 if (NULL == av->excess_cb)
156 return; /* nothing to do */
157 now = GNUNET_TIME_absolute_get ();
158 delta_time = now.abs_value_us - av->last_update__.abs_value_us;
160 (delta_time * ((unsigned long long) av->available_bytes_per_s__) +
161 500000LL) / 1000000LL;
162 current_consumption = av->consumption_since_last_update__ - delta_avail;
163 /* negative current_consumption means that we have savings */
164 max_carry = av->available_bytes_per_s__ * av->max_carry_s__;
165 if (max_carry < GNUNET_SERVER_MAX_MESSAGE_SIZE)
166 max_carry = GNUNET_SERVER_MAX_MESSAGE_SIZE;
167 left_bytes = max_carry + current_consumption;
168 /* left_bytes now contains the number of bytes needed until
169 we have more savings than allowed */
172 /* having excess already */
173 delay = GNUNET_TIME_UNIT_ZERO;
177 delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
179 delay = GNUNET_TIME_relative_divide (delay,
180 av->available_bytes_per_s__);
182 if (GNUNET_SCHEDULER_NO_TASK != av->excess_task)
183 GNUNET_SCHEDULER_cancel (av->excess_task);
184 av->excess_task = GNUNET_SCHEDULER_add_delayed (delay,
191 * Initialize bandwidth tracker. Note that in addition to the
192 * 'max_carry_s' limit, we also always allow at least
193 * #GNUNET_SERVER_MAX_MESSAGE_SIZE to accumulate. So if the
194 * bytes-per-second limit is so small that within 'max_carry_s' not
195 * even #GNUNET_SERVER_MAX_MESSAGE_SIZE is allowed to accumulate, it is
196 * ignored and replaced by #GNUNET_SERVER_MAX_MESSAGE_SIZE (which is in
199 * @param av tracker to initialize
200 * @param update_cb callback to notify a client about the tracker being updated
201 * @param update_cb_cls cls for the callback
202 * @param bytes_per_second_limit initial limit to assume
203 * @param max_carry_s maximum number of seconds unused bandwidth
204 * may accumulate before it expires
205 * @param excess_cb callback to notify if we have excess bandwidth
206 * @param excess_cb_cls closure for @a excess_cb
209 GNUNET_BANDWIDTH_tracker_init2 (struct GNUNET_BANDWIDTH_Tracker *av,
210 GNUNET_BANDWIDTH_TrackerUpdateCallback update_cb,
212 struct GNUNET_BANDWIDTH_Value32NBO bytes_per_second_limit,
213 uint32_t max_carry_s,
214 GNUNET_BANDWIDTH_ExcessNotificationCallback excess_cb,
217 av->update_cb = update_cb;
218 av->update_cb_cls = update_cb_cls;
219 av->consumption_since_last_update__ = 0;
220 av->last_update__ = GNUNET_TIME_absolute_get ();
221 av->available_bytes_per_s__ = ntohl (bytes_per_second_limit.value__);
222 av->max_carry_s__ = max_carry_s;
223 av->excess_cb = excess_cb;
224 av->excess_cb_cls = excess_cb_cls;
225 LOG (GNUNET_ERROR_TYPE_DEBUG,
226 "Tracker %p initialized with %u Bps and max carry %u\n",
228 (unsigned int) av->available_bytes_per_s__,
229 (unsigned int) max_carry_s);
235 * Initialize bandwidth tracker. Note that in addition to the
236 * 'max_carry_s' limit, we also always allow at least
237 * GNUNET_SERVER_MAX_MESSAGE_SIZE to accumulate. So if the
238 * bytes-per-second limit is so small that within 'max_carry_s' not
239 * even GNUNET_SERVER_MAX_MESSAGE_SIZE is allowed to accumulate, it is
240 * ignored and replaced by GNUNET_SERVER_MAX_MESSAGE_SIZE (which is in
243 * @param av tracker to initialize
244 * @param update_cb callback to notify a client about the tracker being updated
245 * @param update_cb_cls cls for the callback
246 * @param bytes_per_second_limit initial limit to assume
247 * @param max_carry_s maximum number of seconds unused bandwidth
248 * may accumulate before it expires
251 GNUNET_BANDWIDTH_tracker_init (struct GNUNET_BANDWIDTH_Tracker *av,
252 GNUNET_BANDWIDTH_TrackerUpdateCallback update_cb,
254 struct GNUNET_BANDWIDTH_Value32NBO bytes_per_second_limit,
255 uint32_t max_carry_s)
257 GNUNET_BANDWIDTH_tracker_init2 (av, update_cb,
259 bytes_per_second_limit,
266 * Stop notifying about tracker updates and excess notifications
268 * @param av the respective trackers
271 GNUNET_BANDWIDTH_tracker_notification_stop (struct GNUNET_BANDWIDTH_Tracker *av)
273 if (GNUNET_SCHEDULER_NO_TASK != av->excess_task)
274 GNUNET_SCHEDULER_cancel (av->excess_task);
275 av->excess_task = GNUNET_SCHEDULER_NO_TASK;
276 av->excess_cb = NULL;
277 av->excess_cb_cls = NULL;
278 av->update_cb = NULL;
279 av->update_cb_cls = NULL;
285 * Update the tracker, looking at the current time and
286 * bandwidth consumption data.
288 * @param av tracker to update
291 update_tracker (struct GNUNET_BANDWIDTH_Tracker *av)
293 struct GNUNET_TIME_Absolute now;
294 struct GNUNET_TIME_Relative delta;
296 uint64_t delta_avail;
300 now = GNUNET_TIME_absolute_get ();
301 delta_time = now.abs_value_us - av->last_update__.abs_value_us;
303 (delta_time * ((unsigned long long) av->available_bytes_per_s__) +
304 500000LL) / 1000000LL;
305 av->consumption_since_last_update__ -= delta_avail;
306 av->last_update__ = now;
307 if (av->consumption_since_last_update__ < 0)
309 left_bytes = -av->consumption_since_last_update__;
310 max_carry = av->available_bytes_per_s__ * av->max_carry_s__;
311 if (max_carry < GNUNET_SERVER_MAX_MESSAGE_SIZE)
312 max_carry = GNUNET_SERVER_MAX_MESSAGE_SIZE;
313 if (max_carry > left_bytes)
314 av->consumption_since_last_update__ = -left_bytes;
316 av->consumption_since_last_update__ = -max_carry;
318 delta.rel_value_us = delta_time;
319 LOG (GNUNET_ERROR_TYPE_DEBUG,
320 "Tracker %p updated, have %u Bps, last update was %s ago\n", av,
321 (unsigned int) av->available_bytes_per_s__,
322 GNUNET_STRINGS_relative_time_to_string (delta, GNUNET_YES));
327 * Notify the tracker that a certain number of bytes of bandwidth have
328 * been consumed. Note that it is legal to consume bytes even if not
329 * enough bandwidth is available (in that case,
330 * #GNUNET_BANDWIDTH_tracker_get_delay may return non-zero delay values
331 * even for a size of zero for a while).
333 * @param av tracker to update
334 * @param size number of bytes consumed
335 * @return #GNUNET_YES if this consumption is above the limit
338 GNUNET_BANDWIDTH_tracker_consume (struct GNUNET_BANDWIDTH_Tracker *av,
343 LOG (GNUNET_ERROR_TYPE_DEBUG,
344 "Tracker %p consumes %d bytes\n",
349 nc = av->consumption_since_last_update__ + size;
350 if (nc < av->consumption_since_last_update__)
353 return GNUNET_SYSERR;
355 av->consumption_since_last_update__ = nc;
358 if (av->consumption_since_last_update__ > 0)
360 LOG (GNUNET_ERROR_TYPE_DEBUG,
361 "Tracker %p consumption %llu bytes above limit\n", av,
362 (unsigned long long) av->consumption_since_last_update__);
368 av->consumption_since_last_update__ += size;
376 * Compute how long we should wait until consuming 'size'
377 * bytes of bandwidth in order to stay within the given
380 * @param av tracker to query
381 * @param size number of bytes we would like to consume
382 * @return time in ms to wait for consumption to be OK
384 struct GNUNET_TIME_Relative
385 GNUNET_BANDWIDTH_tracker_get_delay (struct GNUNET_BANDWIDTH_Tracker *av,
388 struct GNUNET_TIME_Relative ret;
389 int64_t bytes_needed;
391 if (0 == av->available_bytes_per_s__)
393 LOG (GNUNET_ERROR_TYPE_DEBUG,
394 "Tracker %p delay is infinity\n", av);
395 return GNUNET_TIME_UNIT_FOREVER_REL;
398 bytes_needed = size + av->consumption_since_last_update__;
399 if (bytes_needed <= 0)
401 LOG (GNUNET_ERROR_TYPE_DEBUG,
402 "Tracker %p delay for %u bytes is zero\n", av,
403 (unsigned int) size);
404 return GNUNET_TIME_UNIT_ZERO;
407 (1000LL * 1000LL * bytes_needed) /
408 (unsigned long long) av->available_bytes_per_s__;
409 LOG (GNUNET_ERROR_TYPE_DEBUG,
410 "Tracker %p delay for %u bytes is %s\n",
411 av, (unsigned int) size,
412 GNUNET_STRINGS_relative_time_to_string (ret, GNUNET_YES));
418 * Compute how many bytes are available for consumption right now.
421 * @param av tracker to query
422 * @return number of bytes available for consumption right now
425 GNUNET_BANDWIDTH_tracker_get_available (struct GNUNET_BANDWIDTH_Tracker *av)
427 struct GNUNET_BANDWIDTH_Value32NBO bps;
432 bps = GNUNET_BANDWIDTH_value_init (av->available_bytes_per_s__);
434 GNUNET_BANDWIDTH_value_get_available_until (bps,
435 GNUNET_TIME_absolute_get_duration
436 (av->last_update__));
437 used = av->consumption_since_last_update__;
438 LOG (GNUNET_ERROR_TYPE_DEBUG,
439 "Tracker %p available bandwidth is %lld bytes\n", av,
440 (long long) (int64_t) (avail - used));
441 return (int64_t) (avail - used);
446 * Update quota of bandwidth tracker.
448 * @param av tracker to initialize
449 * @param bytes_per_second_limit new limit to assume
452 GNUNET_BANDWIDTH_tracker_update_quota (struct GNUNET_BANDWIDTH_Tracker *av,
453 struct GNUNET_BANDWIDTH_Value32NBO bytes_per_second_limit)
458 new_limit = ntohl (bytes_per_second_limit.value__);
459 LOG (GNUNET_ERROR_TYPE_DEBUG,
460 "Tracker %p bandwidth changed to %u Bps\n", av,
461 (unsigned int) new_limit);
463 old_limit = av->available_bytes_per_s__;
464 av->available_bytes_per_s__ = new_limit;
465 if (NULL != av->update_cb)
466 av->update_cb (av->update_cb_cls);
467 if (old_limit > new_limit)
468 update_tracker (av); /* maximum excess might be less now */
473 /* end of bandwidth.c */