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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;
135 av->excess_cb (av->excess_cb_cls);
140 * Recalculate when we might need to call the excess callback.
143 update_excess (struct GNUNET_BANDWIDTH_Tracker *av)
145 struct GNUNET_TIME_Relative delay;
146 struct GNUNET_TIME_Absolute now;
148 uint64_t delta_avail;
151 int64_t current_consumption;
153 if (NULL == av->excess_cb)
154 return; /* nothing to do */
155 now = GNUNET_TIME_absolute_get ();
156 delta_time = now.abs_value_us - av->last_update__.abs_value_us;
158 (delta_time * ((unsigned long long) av->available_bytes_per_s__) +
159 500000LL) / 1000000LL;
160 current_consumption = av->consumption_since_last_update__ - delta_avail;
161 /* negative current_consumption means that we have savings */
162 max_carry = av->available_bytes_per_s__ * av->max_carry_s__;
163 if (max_carry < GNUNET_SERVER_MAX_MESSAGE_SIZE)
164 max_carry = GNUNET_SERVER_MAX_MESSAGE_SIZE;
165 left_bytes = max_carry + current_consumption;
166 /* left_bytes now contains the number of bytes needed until
167 we have more savings than allowed */
170 /* having excess already */
171 delay = GNUNET_TIME_UNIT_ZERO;
175 delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
177 delay = GNUNET_TIME_relative_divide (delay,
178 av->available_bytes_per_s__);
180 if (GNUNET_SCHEDULER_NO_TASK != av->excess_task)
181 GNUNET_SCHEDULER_cancel (av->excess_task);
182 av->excess_task = GNUNET_SCHEDULER_add_delayed (delay,
189 * Initialize bandwidth tracker. Note that in addition to the
190 * 'max_carry_s' limit, we also always allow at least
191 * #GNUNET_SERVER_MAX_MESSAGE_SIZE to accumulate. So if the
192 * bytes-per-second limit is so small that within 'max_carry_s' not
193 * even #GNUNET_SERVER_MAX_MESSAGE_SIZE is allowed to accumulate, it is
194 * ignored and replaced by #GNUNET_SERVER_MAX_MESSAGE_SIZE (which is in
197 * @param av tracker to initialize
198 * @param update_cb callback to notify a client about the tracker being updated
199 * @param update_cb_cls cls for the callback
200 * @param bytes_per_second_limit initial limit to assume
201 * @param max_carry_s maximum number of seconds unused bandwidth
202 * may accumulate before it expires
203 * @param excess_cb callback to notify if we have excess bandwidth
204 * @param excess_cb_cls closure for @a excess_cb
207 GNUNET_BANDWIDTH_tracker_init2 (struct GNUNET_BANDWIDTH_Tracker *av,
208 GNUNET_BANDWIDTH_TrackerUpdateCallback update_cb,
210 struct GNUNET_BANDWIDTH_Value32NBO bytes_per_second_limit,
211 uint32_t max_carry_s,
212 GNUNET_BANDWIDTH_ExcessNotificationCallback excess_cb,
215 av->update_cb = update_cb;
216 av->update_cb_cls = update_cb_cls;
217 av->consumption_since_last_update__ = 0;
218 av->last_update__ = GNUNET_TIME_absolute_get ();
219 av->available_bytes_per_s__ = ntohl (bytes_per_second_limit.value__);
220 av->max_carry_s__ = max_carry_s;
221 av->excess_cb = excess_cb;
222 av->excess_cb_cls = excess_cb_cls;
223 LOG (GNUNET_ERROR_TYPE_DEBUG,
224 "Tracker %p initialized with %u Bps and max carry %u\n",
226 (unsigned int) av->available_bytes_per_s__,
227 (unsigned int) max_carry_s);
233 * Initialize bandwidth tracker. Note that in addition to the
234 * 'max_carry_s' limit, we also always allow at least
235 * GNUNET_SERVER_MAX_MESSAGE_SIZE to accumulate. So if the
236 * bytes-per-second limit is so small that within 'max_carry_s' not
237 * even GNUNET_SERVER_MAX_MESSAGE_SIZE is allowed to accumulate, it is
238 * ignored and replaced by GNUNET_SERVER_MAX_MESSAGE_SIZE (which is in
241 * @param av tracker to initialize
242 * @param update_cb callback to notify a client about the tracker being updated
243 * @param update_cb_cls cls for the callback
244 * @param bytes_per_second_limit initial limit to assume
245 * @param max_carry_s maximum number of seconds unused bandwidth
246 * may accumulate before it expires
249 GNUNET_BANDWIDTH_tracker_init (struct GNUNET_BANDWIDTH_Tracker *av,
250 GNUNET_BANDWIDTH_TrackerUpdateCallback update_cb,
252 struct GNUNET_BANDWIDTH_Value32NBO bytes_per_second_limit,
253 uint32_t max_carry_s)
255 GNUNET_BANDWIDTH_tracker_init2 (av, update_cb,
257 bytes_per_second_limit,
264 * Update the tracker, looking at the current time and
265 * bandwidth consumption data.
267 * @param av tracker to update
270 update_tracker (struct GNUNET_BANDWIDTH_Tracker *av)
272 struct GNUNET_TIME_Absolute now;
273 struct GNUNET_TIME_Relative delta;
275 uint64_t delta_avail;
279 now = GNUNET_TIME_absolute_get ();
280 delta_time = now.abs_value_us - av->last_update__.abs_value_us;
282 (delta_time * ((unsigned long long) av->available_bytes_per_s__) +
283 500000LL) / 1000000LL;
284 av->consumption_since_last_update__ -= delta_avail;
285 av->last_update__ = now;
286 if (av->consumption_since_last_update__ < 0)
288 left_bytes = -av->consumption_since_last_update__;
289 max_carry = av->available_bytes_per_s__ * av->max_carry_s__;
290 if (max_carry < GNUNET_SERVER_MAX_MESSAGE_SIZE)
291 max_carry = GNUNET_SERVER_MAX_MESSAGE_SIZE;
292 if (max_carry > left_bytes)
293 av->consumption_since_last_update__ = -left_bytes;
295 av->consumption_since_last_update__ = -max_carry;
297 delta.rel_value_us = delta_time;
298 LOG (GNUNET_ERROR_TYPE_DEBUG,
299 "Tracker %p updated, have %u Bps, last update was %s ago\n", av,
300 (unsigned int) av->available_bytes_per_s__,
301 GNUNET_STRINGS_relative_time_to_string (delta, GNUNET_YES));
306 * Notify the tracker that a certain number of bytes of bandwidth have
307 * been consumed. Note that it is legal to consume bytes even if not
308 * enough bandwidth is available (in that case,
309 * #GNUNET_BANDWIDTH_tracker_get_delay may return non-zero delay values
310 * even for a size of zero for a while).
312 * @param av tracker to update
313 * @param size number of bytes consumed
314 * @return #GNUNET_YES if this consumption is above the limit
317 GNUNET_BANDWIDTH_tracker_consume (struct GNUNET_BANDWIDTH_Tracker *av,
322 LOG (GNUNET_ERROR_TYPE_DEBUG,
323 "Tracker %p consumes %d bytes\n",
328 nc = av->consumption_since_last_update__ + size;
329 if (nc < av->consumption_since_last_update__)
332 return GNUNET_SYSERR;
334 av->consumption_since_last_update__ = nc;
337 if (av->consumption_since_last_update__ > 0)
339 LOG (GNUNET_ERROR_TYPE_DEBUG,
340 "Tracker %p consumption %llu bytes above limit\n", av,
341 (unsigned long long) av->consumption_since_last_update__);
347 av->consumption_since_last_update__ += size;
355 * Compute how long we should wait until consuming 'size'
356 * bytes of bandwidth in order to stay within the given
359 * @param av tracker to query
360 * @param size number of bytes we would like to consume
361 * @return time in ms to wait for consumption to be OK
363 struct GNUNET_TIME_Relative
364 GNUNET_BANDWIDTH_tracker_get_delay (struct GNUNET_BANDWIDTH_Tracker *av,
367 struct GNUNET_TIME_Relative ret;
368 int64_t bytes_needed;
370 if (0 == av->available_bytes_per_s__)
372 LOG (GNUNET_ERROR_TYPE_DEBUG,
373 "Tracker %p delay is infinity\n", av);
374 return GNUNET_TIME_UNIT_FOREVER_REL;
377 bytes_needed = size + av->consumption_since_last_update__;
378 if (bytes_needed <= 0)
380 LOG (GNUNET_ERROR_TYPE_DEBUG,
381 "Tracker %p delay for %u bytes is zero\n", av,
382 (unsigned int) size);
383 return GNUNET_TIME_UNIT_ZERO;
386 (1000LL * 1000LL * bytes_needed) /
387 (unsigned long long) av->available_bytes_per_s__;
388 LOG (GNUNET_ERROR_TYPE_DEBUG,
389 "Tracker %p delay for %u bytes is %s\n",
390 av, (unsigned int) size,
391 GNUNET_STRINGS_relative_time_to_string (ret, GNUNET_YES));
397 * Compute how many bytes are available for consumption right now.
400 * @param av tracker to query
401 * @return number of bytes available for consumption right now
404 GNUNET_BANDWIDTH_tracker_get_available (struct GNUNET_BANDWIDTH_Tracker *av)
406 struct GNUNET_BANDWIDTH_Value32NBO bps;
411 bps = GNUNET_BANDWIDTH_value_init (av->available_bytes_per_s__);
413 GNUNET_BANDWIDTH_value_get_available_until (bps,
414 GNUNET_TIME_absolute_get_duration
415 (av->last_update__));
416 used = av->consumption_since_last_update__;
417 LOG (GNUNET_ERROR_TYPE_DEBUG,
418 "Tracker %p available bandwidth is %lld bytes\n", av,
419 (long long) (int64_t) (avail - used));
420 return (int64_t) (avail - used);
425 * Update quota of bandwidth tracker.
427 * @param av tracker to initialize
428 * @param bytes_per_second_limit new limit to assume
431 GNUNET_BANDWIDTH_tracker_update_quota (struct GNUNET_BANDWIDTH_Tracker *av,
432 struct GNUNET_BANDWIDTH_Value32NBO bytes_per_second_limit)
437 new_limit = ntohl (bytes_per_second_limit.value__);
438 LOG (GNUNET_ERROR_TYPE_DEBUG,
439 "Tracker %p bandwidth changed to %u Bps\n", av,
440 (unsigned int) new_limit);
442 old_limit = av->available_bytes_per_s__;
443 av->available_bytes_per_s__ = new_limit;
444 if (NULL != av->update_cb)
445 av->update_cb (av->update_cb_cls);
446 if (old_limit > new_limit)
447 update_tracker (av); /* maximum excess might be less now */
452 /* end of bandwidth.c */