2 This file is part of GNUnet.
3 (C) 2010 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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22 * @file util/bandwidth.c
23 * @brief functions related to bandwidth (unit)
24 * @author Christian Grothoff
27 #include "gnunet_bandwidth_lib.h"
28 #include "gnunet_server_lib.h"
30 #define DEBUG_BANDWIDTH GNUNET_NO
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;
44 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Initializing bandwidth of %u Bps\n",
45 (unsigned int) bytes_per_second);
47 ret.value__ = htonl (bytes_per_second);
53 * Compute the MIN of two bandwidth values.
55 * @param b1 first value
56 * @param b2 second value
57 * @return the min of b1 and b2
59 struct GNUNET_BANDWIDTH_Value32NBO
60 GNUNET_BANDWIDTH_value_min (struct GNUNET_BANDWIDTH_Value32NBO b1,
61 struct GNUNET_BANDWIDTH_Value32NBO b2)
64 GNUNET_BANDWIDTH_value_init (GNUNET_MIN
65 (ntohl (b1.value__), ntohl (b2.value__)));
70 * At the given bandwidth, calculate how much traffic will be
71 * available until the given deadline.
73 * @param bps bandwidth
74 * @param deadline when is the deadline
75 * @return number of bytes available at bps until deadline
78 GNUNET_BANDWIDTH_value_get_available_until (struct GNUNET_BANDWIDTH_Value32NBO
80 struct GNUNET_TIME_Relative
85 b = ntohl (bps.value__);
87 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
88 "Bandwidth has %llu bytes available until deadline in %llums\n",
89 (unsigned long long) ((b * deadline.rel_value + 500LL) / 1000LL),
92 return (b * deadline.rel_value + 500LL) / 1000LL;
97 * At the given bandwidth, calculate how long it would take for
98 * 'size' bytes to be transmitted.
100 * @param bps bandwidth
101 * @param size number of bytes we want to have available
102 * @return how long it would take
104 struct GNUNET_TIME_Relative
105 GNUNET_BANDWIDTH_value_get_delay_for (struct GNUNET_BANDWIDTH_Value32NBO bps,
109 struct GNUNET_TIME_Relative ret;
111 b = ntohl (bps.value__);
115 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
116 "Bandwidth suggests delay of infinity (zero bandwidth)\n");
118 return GNUNET_TIME_UNIT_FOREVER_REL;
120 ret.rel_value = size * 1000LL / b;
122 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
123 "Bandwidth suggests delay of %llu ms for %llu bytes of traffic\n",
124 (unsigned long long) ret.rel_value, (unsigned long long) size);
131 * Initialize bandwidth tracker. Note that in addition to the
132 * 'max_carry_s' limit, we also always allow at least
133 * GNUNET_SERVER_MAX_MESSAGE_SIZE to accumulate. So if the
134 * bytes-per-second limit is so small that within 'max_carry_s' not
135 * even GNUNET_SERVER_MAX_MESSAGE_SIZE is allowed to accumulate, it is
136 * ignored and replaced by GNUNET_SERVER_MAX_MESSAGE_SIZE (which is in
139 * @param av tracker to initialize
140 * @param bytes_per_second_limit initial limit to assume
141 * @param max_carry_s maximum number of seconds unused bandwidth
142 * may accumulate before it expires
145 GNUNET_BANDWIDTH_tracker_init (struct GNUNET_BANDWIDTH_Tracker *av,
146 struct GNUNET_BANDWIDTH_Value32NBO
147 bytes_per_second_limit, uint32_t max_carry_s)
149 av->consumption_since_last_update__ = 0;
150 av->last_update__ = GNUNET_TIME_absolute_get ();
151 av->available_bytes_per_s__ = ntohl (bytes_per_second_limit.value__);
152 av->max_carry_s__ = max_carry_s;
154 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
155 "Tracker %p initialized with %u Bps and max carry %u\n", av,
156 (unsigned int) av->available_bytes_per_s__,
157 (unsigned int) max_carry_s);
163 * Update the tracker, looking at the current time and
164 * bandwidth consumption data.
166 * @param av tracker to update
169 update_tracker (struct GNUNET_BANDWIDTH_Tracker *av)
171 struct GNUNET_TIME_Absolute now;
173 uint64_t delta_avail;
177 now = GNUNET_TIME_absolute_get ();
178 delta_time = now.abs_value - av->last_update__.abs_value;
180 (delta_time * ((unsigned long long) av->available_bytes_per_s__) +
182 av->consumption_since_last_update__ -= delta_avail;
183 av->last_update__ = now;
184 if (av->consumption_since_last_update__ < 0)
186 left_bytes = -av->consumption_since_last_update__;
187 max_carry = av->available_bytes_per_s__ * av->max_carry_s__;
188 if (max_carry < GNUNET_SERVER_MAX_MESSAGE_SIZE)
189 max_carry = GNUNET_SERVER_MAX_MESSAGE_SIZE;
190 if (max_carry > left_bytes)
191 av->consumption_since_last_update__ = -left_bytes;
193 av->consumption_since_last_update__ = -max_carry;
196 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
197 "Tracker %p updated, have %u Bps, last update was %llu ms ago\n",
198 av, (unsigned int) av->available_bytes_per_s__,
199 (unsigned long long) delta_time);
206 * Notify the tracker that a certain number of bytes of bandwidth have
207 * been consumed. Note that it is legal to consume bytes even if not
208 * enough bandwidth is available (in that case,
209 * GNUNET_BANDWIDTH_tracker_get_delay may return non-zero delay values
210 * even for a size of zero for a while).
212 * @param av tracker to update
213 * @param size number of bytes consumed
214 * @return GNUNET_YES if this consumption is above the limit
217 GNUNET_BANDWIDTH_tracker_consume (struct GNUNET_BANDWIDTH_Tracker *av,
223 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Tracker %p consumes %d bytes\n", av,
228 nc = av->consumption_since_last_update__ + size;
229 if (nc < av->consumption_since_last_update__)
232 return GNUNET_SYSERR;
234 av->consumption_since_last_update__ = nc;
236 if (av->consumption_since_last_update__ > 0)
239 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
240 "Tracker %p consumption %llu bytes above limit\n", av,
241 (unsigned long long) av->consumption_since_last_update__);
248 av->consumption_since_last_update__ += size;
255 * Compute how long we should wait until consuming 'size'
256 * bytes of bandwidth in order to stay within the given
259 * @param av tracker to query
260 * @param size number of bytes we would like to consume
261 * @return time in ms to wait for consumption to be OK
263 struct GNUNET_TIME_Relative
264 GNUNET_BANDWIDTH_tracker_get_delay (struct GNUNET_BANDWIDTH_Tracker *av,
267 struct GNUNET_TIME_Relative ret;
268 int64_t bytes_needed;
270 if (av->available_bytes_per_s__ == 0)
273 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Tracker %p delay is infinity\n", av);
275 return GNUNET_TIME_UNIT_FOREVER_REL;
278 bytes_needed = size + av->consumption_since_last_update__;
279 if (bytes_needed <= 0)
282 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
283 "Tracker %p delay for %u bytes is zero\n", av,
284 (unsigned int) size);
286 return GNUNET_TIME_UNIT_ZERO;
289 1000LL * bytes_needed / (unsigned long long) av->available_bytes_per_s__;
291 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
292 "Tracker %p delay for %u bytes is %llu ms\n", av,
293 (unsigned int) size, (unsigned long long) ret.rel_value);
300 * Compute how many bytes are available for consumption right now.
303 * @param av tracker to query
304 * @return number of bytes available for consumption right now
307 GNUNET_BANDWIDTH_tracker_get_available (struct GNUNET_BANDWIDTH_Tracker * av)
309 struct GNUNET_BANDWIDTH_Value32NBO bps;
314 bps = GNUNET_BANDWIDTH_value_init (av->available_bytes_per_s__);
316 GNUNET_BANDWIDTH_value_get_available_until (bps,
317 GNUNET_TIME_absolute_get_duration
318 (av->last_update__));
319 used = av->consumption_since_last_update__;
321 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
322 "Tracker %p available bandwidth is %lld bytes\n", av,
323 (long long) (int64_t) (avail - used));
325 return (int64_t) (avail - used);
330 * Update quota of bandwidth tracker.
332 * @param av tracker to initialize
333 * @param bytes_per_second_limit new limit to assume
336 GNUNET_BANDWIDTH_tracker_update_quota (struct GNUNET_BANDWIDTH_Tracker *av,
337 struct GNUNET_BANDWIDTH_Value32NBO
338 bytes_per_second_limit)
343 new_limit = ntohl (bytes_per_second_limit.value__);
345 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
346 "Tracker %p bandwidth changed to %u Bps\n", av,
347 (unsigned int) new_limit);
350 old_limit = av->available_bytes_per_s__;
351 av->available_bytes_per_s__ = new_limit;
352 if (old_limit > new_limit)
353 update_tracker (av); /* maximum excess might be less now */
357 /* end of bandwidth.c */