2 This file is part of GNUnet.
3 (C) 2010 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_bandwidth_lib.h"
28 #include "gnunet_server_lib.h"
30 #define DEBUG_BANDWIDTH GNUNET_EXTRA_LOGGING
32 #define LOG(kind,...) GNUNET_log_from (kind, "util",__VA_ARGS__)
35 * Create a new bandwidth value.
37 * @param bytes_per_second value to create
38 * @return the new bandwidth value
40 struct GNUNET_BANDWIDTH_Value32NBO
41 GNUNET_BANDWIDTH_value_init (uint32_t bytes_per_second)
43 struct GNUNET_BANDWIDTH_Value32NBO ret;
46 LOG (GNUNET_ERROR_TYPE_DEBUG, "Initializing bandwidth of %u Bps\n",
47 (unsigned int) bytes_per_second);
49 ret.value__ = htonl (bytes_per_second);
55 * Compute the MIN of two bandwidth values.
57 * @param b1 first value
58 * @param b2 second value
59 * @return the min of b1 and b2
61 struct GNUNET_BANDWIDTH_Value32NBO
62 GNUNET_BANDWIDTH_value_min (struct GNUNET_BANDWIDTH_Value32NBO b1,
63 struct GNUNET_BANDWIDTH_Value32NBO b2)
66 GNUNET_BANDWIDTH_value_init (GNUNET_MIN
67 (ntohl (b1.value__), ntohl (b2.value__)));
72 * At the given bandwidth, calculate how much traffic will be
73 * available until the given deadline.
75 * @param bps bandwidth
76 * @param deadline when is the deadline
77 * @return number of bytes available at bps until deadline
80 GNUNET_BANDWIDTH_value_get_available_until (struct GNUNET_BANDWIDTH_Value32NBO
82 struct GNUNET_TIME_Relative
87 b = ntohl (bps.value__);
89 LOG (GNUNET_ERROR_TYPE_DEBUG,
90 "Bandwidth has %llu bytes available until deadline in %llums\n",
91 (unsigned long long) ((b * deadline.rel_value + 500LL) / 1000LL),
94 return (b * deadline.rel_value + 500LL) / 1000LL;
99 * At the given bandwidth, calculate how long it would take for
100 * 'size' bytes to be transmitted.
102 * @param bps bandwidth
103 * @param size number of bytes we want to have available
104 * @return how long it would take
106 struct GNUNET_TIME_Relative
107 GNUNET_BANDWIDTH_value_get_delay_for (struct GNUNET_BANDWIDTH_Value32NBO bps,
111 struct GNUNET_TIME_Relative ret;
113 b = ntohl (bps.value__);
117 LOG (GNUNET_ERROR_TYPE_DEBUG,
118 "Bandwidth suggests delay of infinity (zero bandwidth)\n");
120 return GNUNET_TIME_UNIT_FOREVER_REL;
122 ret.rel_value = size * 1000LL / b;
124 LOG (GNUNET_ERROR_TYPE_DEBUG,
125 "Bandwidth suggests delay of %llu ms for %llu bytes of traffic\n",
126 (unsigned long long) ret.rel_value, (unsigned long long) size);
133 * Initialize bandwidth tracker. Note that in addition to the
134 * 'max_carry_s' limit, we also always allow at least
135 * GNUNET_SERVER_MAX_MESSAGE_SIZE to accumulate. So if the
136 * bytes-per-second limit is so small that within 'max_carry_s' not
137 * even GNUNET_SERVER_MAX_MESSAGE_SIZE is allowed to accumulate, it is
138 * ignored and replaced by GNUNET_SERVER_MAX_MESSAGE_SIZE (which is in
141 * @param av tracker to initialize
142 * @param bytes_per_second_limit initial limit to assume
143 * @param max_carry_s maximum number of seconds unused bandwidth
144 * may accumulate before it expires
147 GNUNET_BANDWIDTH_tracker_init (struct GNUNET_BANDWIDTH_Tracker *av,
148 struct GNUNET_BANDWIDTH_Value32NBO
149 bytes_per_second_limit, uint32_t max_carry_s)
151 av->consumption_since_last_update__ = 0;
152 av->last_update__ = GNUNET_TIME_absolute_get ();
153 av->available_bytes_per_s__ = ntohl (bytes_per_second_limit.value__);
154 av->max_carry_s__ = max_carry_s;
156 LOG (GNUNET_ERROR_TYPE_DEBUG,
157 "Tracker %p initialized with %u Bps and max carry %u\n", av,
158 (unsigned int) av->available_bytes_per_s__, (unsigned int) max_carry_s);
164 * Update the tracker, looking at the current time and
165 * bandwidth consumption data.
167 * @param av tracker to update
170 update_tracker (struct GNUNET_BANDWIDTH_Tracker *av)
172 struct GNUNET_TIME_Absolute now;
174 uint64_t delta_avail;
178 now = GNUNET_TIME_absolute_get ();
179 delta_time = now.abs_value - av->last_update__.abs_value;
181 (delta_time * ((unsigned long long) av->available_bytes_per_s__) +
183 av->consumption_since_last_update__ -= delta_avail;
184 av->last_update__ = now;
185 if (av->consumption_since_last_update__ < 0)
187 left_bytes = -av->consumption_since_last_update__;
188 max_carry = av->available_bytes_per_s__ * av->max_carry_s__;
189 if (max_carry < GNUNET_SERVER_MAX_MESSAGE_SIZE)
190 max_carry = GNUNET_SERVER_MAX_MESSAGE_SIZE;
191 if (max_carry > left_bytes)
192 av->consumption_since_last_update__ = -left_bytes;
194 av->consumption_since_last_update__ = -max_carry;
197 LOG (GNUNET_ERROR_TYPE_DEBUG,
198 "Tracker %p updated, have %u Bps, last update was %llu ms ago\n", av,
199 (unsigned int) av->available_bytes_per_s__,
200 (unsigned long long) delta_time);
207 * Notify the tracker that a certain number of bytes of bandwidth have
208 * been consumed. Note that it is legal to consume bytes even if not
209 * enough bandwidth is available (in that case,
210 * GNUNET_BANDWIDTH_tracker_get_delay may return non-zero delay values
211 * even for a size of zero for a while).
213 * @param av tracker to update
214 * @param size number of bytes consumed
215 * @return GNUNET_YES if this consumption is above the limit
218 GNUNET_BANDWIDTH_tracker_consume (struct GNUNET_BANDWIDTH_Tracker *av,
224 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tracker %p consumes %d bytes\n", av,
229 nc = av->consumption_since_last_update__ + size;
230 if (nc < av->consumption_since_last_update__)
233 return GNUNET_SYSERR;
235 av->consumption_since_last_update__ = nc;
237 if (av->consumption_since_last_update__ > 0)
240 LOG (GNUNET_ERROR_TYPE_DEBUG,
241 "Tracker %p consumption %llu bytes above limit\n", av,
242 (unsigned long long) av->consumption_since_last_update__);
249 av->consumption_since_last_update__ += size;
256 * Compute how long we should wait until consuming 'size'
257 * bytes of bandwidth in order to stay within the given
260 * @param av tracker to query
261 * @param size number of bytes we would like to consume
262 * @return time in ms to wait for consumption to be OK
264 struct GNUNET_TIME_Relative
265 GNUNET_BANDWIDTH_tracker_get_delay (struct GNUNET_BANDWIDTH_Tracker *av,
268 struct GNUNET_TIME_Relative ret;
269 int64_t bytes_needed;
271 if (av->available_bytes_per_s__ == 0)
274 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tracker %p delay is infinity\n", av);
276 return GNUNET_TIME_UNIT_FOREVER_REL;
279 bytes_needed = size + av->consumption_since_last_update__;
280 if (bytes_needed <= 0)
283 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tracker %p delay for %u bytes is zero\n", av,
284 (unsigned int) size);
286 return GNUNET_TIME_UNIT_ZERO;
289 (1000LL * bytes_needed) /
290 (unsigned long long) av->available_bytes_per_s__;
292 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tracker %p delay for %u bytes is %llu ms\n",
293 av, (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 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 LOG (GNUNET_ERROR_TYPE_DEBUG, "Tracker %p bandwidth changed to %u Bps\n", av,
346 (unsigned int) new_limit);
349 old_limit = av->available_bytes_per_s__;
350 av->available_bytes_per_s__ = new_limit;
351 if (old_limit > new_limit)
352 update_tracker (av); /* maximum excess might be less now */
356 /* end of bandwidth.c */