drl/estimate.c

   1 /* See the DRL-LICENSE file for this file's software license. */
   2
   3 /*
   4  * Thread to periodically calculate the estimated local limits
   5  * Barath Raghavan 2006/2007
   6  * Ken Yocum 2007
   7  * Kevin Webb 2007/2008
   8  */
   9
  10 #include <assert.h>
  11
  12 /** The size of the buffer we use to hold tc commands. */
  13 #define CMD_BUFFER_SIZE 200
  14
  15 /* DRL specifics */
  16 #include "raterouter.h"
  17 #include "util.h"
  18 #include "ratetypes.h" /* needs util and pthread.h */
  19 #include "calendar.h"
  20 #include "logging.h"
  21
  22 extern uint8_t system_loglevel;
  23
  24 uint8_t do_enforcement = 0;
  25
  26 /**
  27  * Called for each identity each estimate interval.  Uses flow table information
  28  * to estimate the current aggregate rate and the rate of the individual flows
  29  * in the table.
  30  */
  31 static void estimate(identity_t *ident, const double estintms) {
  32     struct timeval now;
  33     double time_difference;
  34
  35     pthread_mutex_lock(&ident->table_mutex); /* CLUNK ! */
  36
  37     gettimeofday(&now, NULL);
  38
  39     time_difference = timeval_subtract(now, ident->common.last_update);
  40
  41     if (time_difference > 1.05 * (estintms / 1000 * ident->mainloop_intervals)) {
  42         printlog(LOG_WARN, "Missed interval: Scheduled for %.2f ms, actual %.2fms\n",
  43                  estintms * ident->mainloop_intervals, time_difference * 1000);
  44     }
  45
  46     ident->table_update_function(ident->table, now, ident->ewma_weight);
  47
  48 #ifdef SHADOW_ACCTING
  49
  50     standard_table_update_flows((standard_flow_table) ident->shadow_table, now,
  51                                 ident->ewma_weight);
  52
  53 #endif
  54
  55     pthread_mutex_unlock(&ident->table_mutex); /* CLINK ! */
  56 }
  57
  58 /**
  59  * Determines the FPS weight allocation when the identity is under its current
  60  * local rate limit.
  61  */
  62 static double allocate_fps_under_limit(identity_t *ident, uint32_t target, double peer_weights) {
  63     double ideal_weight;
  64     double total_weight = peer_weights + ident->last_localweight;
  65
  66     if (target >= ident->limit) {
  67         ideal_weight = total_weight;
  68     } else if (target <= 0) {
  69         ideal_weight = 0; // no flows here
  70     } else {
  71         ideal_weight = ((double)target / (double)ident->limit) * total_weight;
  72     }
  73
  74 #if 0
  75     else if (peer_weights <= 0) {
  76 #if 0
  77         // doesn't matter what we pick as our weight, so pick 1 / N.
  78         ideal_weight = MAX_FLOW_SCALING_FACTOR / (remote_count(ident->i_handle) + 1);
  79 #endif
  80         ideal_weight = ((double)target / (double)ident->limit) * total_weight;
  81     } else {
  82 #if 0
  83         double divisor = (double) ident->limit - (double) target;
  84         ideal_weight = ((double) target * peer_weights) / divisor;
  85 #else
  86         ideal_weight = ((double)target / (double)ident->limit) * total_weight;
  87 #endif
  88     }
  89 #endif
  90
  91     return ideal_weight;
  92 }
  93
  94 /**
  95  * Determines the FPS weight allocation when the identity is over its current
  96  * local rate limit.
  97  */
  98 static double allocate_fps_over_limit(identity_t *ident) {
  99     double ideal_weight;
 100     double total_over_max;
 101
 102     if (ident->common.max_flow_rate > 0) {
 103         ideal_weight = (double) ident->locallimit / (double) ident->common.max_flow_rate;
 104         total_over_max = (double) ident->common.rate / (double) ident->common.max_flow_rate;
 105
 106         printlog(LOG_DEBUG, "ideal_over: %.3f, limit: %d, max_flow_rate: %d, total_rate: %d, total/max: %.3f\n",
 107                  ideal_weight, ident->locallimit, ident->common.max_flow_rate, ident->common.rate, total_over_max);
 108     } else {
 109         ideal_weight = 1;
 110     }
 111
 112     return ideal_weight;
 113 }
 114
 115 /**
 116  * When FPS checks to see which mode it should be operating in
 117  * (over limit vs under limit), we don't want it to actually look to
 118  * see if we're at the limit.  Instead, we want to see if we're getting
 119  * close to the limit.  This defines how close is "close enough".
 120  *
 121  * For example, if the limit is 50000 and we're sending 49000, we probably
 122  * want to be in the over limit mode, even if we aren't actually over the limit
 123  * in order to switch to the more aggressive weight calculations.
 124  */
 125 static inline uint32_t close_enough(uint32_t limit) {
 126     uint32_t difference = limit - (limit * CLOSE_ENOUGH);
 127
 128     if (difference < 2500) {
 129         return (limit - 2500);
 130     } else {
 131         return (limit * CLOSE_ENOUGH);
 132     }
 133 }
 134
 135 static void print_statistics(identity_t *ident, const double ideal_weight,
 136                              const double total_weight, const double localweight,
 137                              const char *identifier, common_accounting_t *table,
 138                              const uint32_t resulting_limit) {
 139     struct timeval tv;
 140     double time_now;
 141
 142     gettimeofday(&tv, NULL);
 143     time_now = (double) tv.tv_sec + (double) ((double) tv.tv_usec / (double) 1000000);
 144
 145     printlog(LOG_WARN, "%.2f %d %.2f %.2f %.2f %d %d %d %d %d %d %d %d %d %s:%d ",
 146              time_now, table->inst_rate, ideal_weight, localweight, total_weight,
 147              table->num_flows, table->num_flows_5k, table->num_flows_10k,
 148              table->num_flows_20k, table->num_flows_50k, table->avg_rate,
 149              table->max_flow_rate, table->max_flow_rate_flow_hash, resulting_limit,
 150              identifier, ident->id);
 151
 152     if (table->max_flow_rate > 0) {
 153         printlog(LOG_WARN, "%.3f\n", (double) table->rate / (double) table->max_flow_rate);
 154     } else {
 155         printlog(LOG_WARN, "0\n");
 156     }
 157
 158     /* Print to the screen in debug mode. */
 159     if (system_loglevel == LOG_DEBUG) {
 160         printf("Local Rate: %d, Ideal Weight: %.3f, Local Weight: %.3f, Total Weight: %.3f\n",
 161                table->rate, ideal_weight, ident->localweight, total_weight);
 162     }
 163 }
 164
 165 static uint32_t allocate_fps(identity_t *ident, double total_weight,
 166                              common_accounting_t *table, const char *identifier) {
 167
 168     uint32_t resulting_limit = 0;
 169     double ideal_weight = 0.0;
 170     double peer_weights = total_weight - ident->last_localweight;
 171
 172     /* Keep track of these for measurements & comparisons only. */
 173     double ideal_under = 0.0;
 174     double ideal_over = 0.0;
 175
 176     /* Weight sanity. */
 177     if (peer_weights < 0.0) {
 178         peer_weights = 0.0;
 179     }
 180
 181     if (ident->dampen_state == DAMPEN_TEST) {
 182         int64_t rate_delta = (int64_t) table->inst_rate - (int64_t) table->last_inst_rate;
 183         double threshold = (double) ident->limit * (double) LARGE_INCREASE_PERCENTAGE / 10;
 184
 185         if (rate_delta > threshold) {
 186             ident->dampen_state = DAMPEN_PASSED;
 187         } else {
 188             ident->dampen_state = DAMPEN_FAILED;
 189         }
 190     }
 191
 192     /* Rate/weight sanity. */
 193     if (table->rate <= 0) {
 194         ideal_weight = 0.0;
 195     }
 196
 197     /* Under the limit OR we failed our dampening test OR our current
 198      * outgoing traffic rate is under the low "flowstart" watermark. */
 199     else if (ident->dampen_state == DAMPEN_FAILED ||
 200              table->rate < close_enough(ident->locallimit)) {
 201 #if 0
 202              || ident->flowstart) {
 203         uint32_t target_rate = table->rate;
 204
 205         if (ident->flowstart) {
 206             target_rate *= 4;
 207
 208             if (table->rate >= FLOW_START_THRESHOLD) {
 209                 ident->flowstart = false;
 210             }
 211         } else {
 212             /* June 16, 2008 (KCW)
 213              * ident->flowstart gets set initially to one, but it is never set again.  However,
 214              * if a limiter gets flows and then the number of flows drops to zero, it has trouble
 215              * increasing the limit again. */
 216             if (table->rate < FLOW_START_THRESHOLD) {
 217                 ident->flowstart = true;
 218             }
 219         }
 220         Old flowstart code.
 221 #endif
 222
 223         /* Boost low-limits so that they have room to grow. */
 224         if (table->rate < FLOW_START_THRESHOLD) {
 225             ideal_weight = ideal_under = allocate_fps_under_limit(ident, table->rate * 4, peer_weights);
 226         } else {
 227             ideal_weight = ideal_under = allocate_fps_under_limit(ident, table->rate, peer_weights);
 228         }
 229
 230         ideal_over = allocate_fps_over_limit(ident);
 231
 232         if (ideal_over < ideal_under) {
 233             /* Degenerate case in which the agressive weight calculation was
 234              * actually less than the under-the-limit case.  Use it instead
 235              * and skip the dampening check in the next interval. */
 236             ideal_weight = ideal_over;
 237             ident->dampen_state = DAMPEN_SKIP;
 238         } else {
 239             ident->dampen_state = DAMPEN_NONE;
 240         }
 241
 242         /* Apply EWMA. */
 243         ident->localweight = (ident->localweight * ident->ewma_weight +
 244                               ideal_weight * (1 - ident->ewma_weight));
 245     }
 246
 247     /* At or over the limit.  Use the aggressive weight calculation. */
 248     else {
 249         double portion_last_interval = 0.0;
 250         double portion_this_interval = 0.0;
 251
 252         ideal_weight = ideal_over = allocate_fps_over_limit(ident);
 253         ideal_under = allocate_fps_under_limit(ident, table->rate, peer_weights);
 254
 255         /* Apply EWMA. */
 256         ident->localweight = (ident->localweight * ident->ewma_weight +
 257                               ideal_weight * (1 - ident->ewma_weight));
 258
 259         /* Now check whether the result of the aggressive weight calculation
 260          * increases our portion of the weight "too much", in which case we
 261          * dampen it. */
 262
 263         /* Our portion of weight in the whole system during the last interval.*/
 264         portion_last_interval = ident->last_localweight / total_weight;
 265
 266         /* Our proposed portion of weight for the current interval. */
 267         portion_this_interval = ident->localweight / (peer_weights + ident->localweight);
 268
 269         if (ident->dampen_state == DAMPEN_NONE &&
 270             (portion_this_interval - portion_last_interval > LARGE_INCREASE_PERCENTAGE)) {
 271             ident->localweight = ident->last_localweight + (LARGE_INCREASE_PERCENTAGE * total_weight);
 272             ident->dampen_state = DAMPEN_TEST;
 273         } else {
 274             ident->dampen_state = DAMPEN_SKIP;
 275         }
 276     }
 277
 278     /* Add the weight calculated in this interval to the total. */
 279     ident->total_weight = total_weight = ident->localweight + peer_weights;
 280
 281     /* Convert weight value into a rate limit.  If there is no measureable
 282      * weight, do a L/n allocation. */
 283     if (total_weight > 0) {
 284         resulting_limit = (uint32_t) (ident->localweight * ident->limit / total_weight);
 285     } else {
 286         resulting_limit = (uint32_t) (ident->limit / (ident->comm.remote_node_count + 1));
 287     }
 288
 289     print_statistics(ident, ideal_weight, total_weight, ident->localweight,
 290                      identifier, table, resulting_limit);
 291
 292     return resulting_limit;
 293 }
 294
 295 #ifdef SHADOW_ACCTING
 296
 297 /* Runs through the allocate functionality without making any state changes to
 298  * the identity.  Useful for comparisons, especially for comparing standard
 299  * and sample&hold accounting schemes. */
 300 static void allocate_fps_pretend(identity_t *ident, double total_weight,
 301                                  common_accounting_t *table, const char *identifier) {
 302
 303     uint32_t resulting_limit = 0;
 304     double ideal_weight = 0.0;
 305     double peer_weights = total_weight - ident->last_localweight_copy;
 306     double ideal_under = 0.0;
 307     double ideal_over = 0.0;
 308
 309     if (peer_weights < 0.0) {
 310         peer_weights = 0.0;
 311     }
 312
 313     if (ident->dampen_state_copy == DAMPEN_TEST) {
 314         int64_t rate_delta = (int64_t) table->inst_rate - (int64_t) table->last_inst_rate;
 315         double threshold = (double) ident->limit * (double) LARGE_INCREASE_PERCENTAGE / 10;
 316
 317         if (rate_delta > threshold) {
 318             ident->dampen_state_copy = DAMPEN_PASSED;
 319         } else {
 320             ident->dampen_state_copy = DAMPEN_FAILED;
 321         }
 322     }
 323
 324     /* Rate/weight sanity. */
 325     if (table->rate <= 0) {
 326         ideal_weight = 0.0;
 327     }
 328
 329     /* Under the limit OR we failed our dampening test OR our current
 330      * outgoing traffic rate is under the low "flowstart" watermark. */
 331     else if (ident->dampen_state_copy == DAMPEN_FAILED ||
 332              table->rate < close_enough(ident->locallimit)) {
 333
 334         /* Boost low-limits so that they have room to grow. */
 335         if (table->rate < FLOW_START_THRESHOLD) {
 336             ideal_weight = ideal_under = allocate_fps_under_limit(ident, table->rate * 4, peer_weights);
 337         } else {
 338             ideal_weight = ideal_under = allocate_fps_under_limit(ident, table->rate, peer_weights);
 339         }
 340
 341         ideal_over = allocate_fps_over_limit(ident);
 342
 343         if (ideal_over < ideal_under) {
 344             /* Degenerate case in which the agressive weight calculation was
 345              * actually less than the under-the-limit case.  Use it instead
 346              * and skip the dampening check in the next interval. */
 347             ideal_weight = ideal_over;
 348             ident->dampen_state_copy = DAMPEN_SKIP;
 349         } else {
 350             ident->dampen_state_copy = DAMPEN_NONE;
 351         }
 352
 353         /* Apply EWMA. */
 354         ident->localweight_copy = (ident->localweight_copy * ident->ewma_weight +
 355                               ideal_weight * (1 - ident->ewma_weight));
 356     }
 357
 358     /* At or over the limit.  Use the aggressive weight calculation. */
 359     else {
 360         double portion_last_interval = 0.0;
 361         double portion_this_interval = 0.0;
 362
 363         ideal_weight = ideal_over = allocate_fps_over_limit(ident);
 364         ideal_under = allocate_fps_under_limit(ident, table->rate, peer_weights);
 365
 366         /* Apply EWMA. */
 367         ident->localweight_copy = (ident->localweight_copy * ident->ewma_weight +
 368                               ideal_weight * (1 - ident->ewma_weight));
 369
 370         /* Now check whether the result of the aggressive weight calculation
 371          * increases our portion of the weight "too much", in which case we
 372          * dampen it. */
 373
 374         /* Our portion of weight in the whole system during the last interval.*/
 375         portion_last_interval = ident->last_localweight / total_weight;
 376
 377         /* Our proposed portion of weight for the current interval. */
 378         portion_this_interval = ident->localweight_copy / (peer_weights + ident->localweight_copy);
 379
 380         if (ident->dampen_state_copy == DAMPEN_NONE &&
 381             (portion_this_interval - portion_last_interval > LARGE_INCREASE_PERCENTAGE)) {
 382             ident->localweight_copy = ident->last_localweight + (LARGE_INCREASE_PERCENTAGE * total_weight);
 383             ident->dampen_state_copy = DAMPEN_TEST;
 384         } else {
 385             ident->dampen_state_copy = DAMPEN_SKIP;
 386         }
 387     }
 388
 389     /* Add the weight calculated in this interval to the total. */
 390     total_weight = ident->localweight_copy + peer_weights;
 391
 392     /* Convert weight value into a rate limit.  If there is no measureable
 393      * weight, do a L/n allocation. */
 394     if (total_weight > 0) {
 395         resulting_limit = (uint32_t) (ident->localweight_copy * ident->limit / total_weight);
 396     } else {
 397         resulting_limit = (uint32_t) (ident->limit / (ident->comm.remote_node_count + 1));
 398     }
 399
 400     print_statistics(ident, ideal_weight, total_weight, ident->localweight_copy,
 401                      identifier, table, resulting_limit);
 402 }
 403
 404 #endif
 405
 406 /**
 407  * Determines the amount of FPS weight to allocate to the identity during each
 408  * estimate interval.  Note that total_weight includes local weight.
 409  */
 410 static uint32_t allocate_fps_old(identity_t *ident, double total_weight) {
 411     common_accounting_t *ftable = &ident->common; /* Common flow table info */
 412     uint32_t local_rate = ftable->rate;
 413     uint32_t ideallocal = 0;
 414     double peer_weights; /* sum of weights of all other limiters */
 415     double idealweight = 0;
 416     double last_portion = 0;
 417     double this_portion = 0;
 418
 419     static int dampen = 0;
 420     int dampen_increase = 0;
 421
 422     double ideal_under = 0;
 423     double ideal_over = 0;
 424
 425     int regime = 0;
 426
 427     /* two cases:
 428        1. the aggregate is < limit
 429        2. the aggregate is >= limit
 430        */
 431     peer_weights = total_weight - ident->last_localweight;
 432     if (peer_weights < 0) {
 433         peer_weights = 0;
 434     }
 435
 436     if (dampen == 1) {
 437         int64_t rate_delta =
 438             (int64_t) ftable->inst_rate - (int64_t) ftable->last_inst_rate;
 439         double threshold =
 440             (double) ident->limit * (double) LARGE_INCREASE_PERCENTAGE / 10;
 441
 442         if (rate_delta > threshold) {
 443             dampen_increase = 1;
 444             printlog(LOG_DEBUG, "DAMPEN: delta(%.3f) thresh(%.3f)\n",
 445                      rate_delta, threshold);
 446         }
 447     }
 448
 449     if (local_rate <= 0) {
 450         idealweight = 0;
 451     } else if (dampen_increase == 0 &&
 452                (ident->locallimit <= 0 || local_rate < close_enough(ident->locallimit) || ident->flowstart)) {
 453         /* We're under the limit - all flows are bottlenecked. */
 454         idealweight = allocate_fps_under_limit(ident, local_rate, peer_weights);
 455         ideal_over = allocate_fps_over_limit(ident);
 456         ideal_under = idealweight;
 457
 458         if (ideal_over < idealweight) {
 459             idealweight = ideal_over;
 460             regime = 3;
 461             dampen = 2;
 462         } else {
 463             regime = 1;
 464             dampen = 0;
 465         }
 466
 467         /* Apply EWMA */
 468         ident->localweight = (ident->localweight * ident->ewma_weight +
 469                               idealweight * (1 - ident->ewma_weight));
 470
 471     } else {
 472         idealweight = allocate_fps_over_limit(ident);
 473
 474         /* Apply EWMA */
 475         ident->localweight = (ident->localweight * ident->ewma_weight +
 476                               idealweight * (1 - ident->ewma_weight));
 477
 478         /* This is the portion of the total weight in the system that was caused
 479          * by this limiter in the last interval. */
 480         last_portion = ident->last_localweight / total_weight;
 481
 482         /* This is the fraction of the total weight in the system that our
 483          * proposed value for idealweight would use. */
 484         this_portion = ident->localweight / (peer_weights + ident->localweight);
 485
 486         /* Dampen the large increase the first time... */
 487         if (dampen == 0 && (this_portion - last_portion > LARGE_INCREASE_PERCENTAGE)) {
 488             ident->localweight = ident->last_localweight + (LARGE_INCREASE_PERCENTAGE * total_weight);
 489             dampen = 1;
 490         } else {
 491             dampen = 2;
 492         }
 493
 494         ideal_under = allocate_fps_under_limit(ident, local_rate, peer_weights);
 495         ideal_over = idealweight;
 496
 497         regime = 2;
 498     }
 499
 500     /* Convert weight into a rate - add in our new local weight */
 501     ident->total_weight = total_weight = ident->localweight + peer_weights;
 502
 503     /* compute local allocation:
 504        if there is traffic elsewhere, use the weights
 505        otherwise do a L/n allocation */
 506     if (total_weight > 0) {
 507     //if (peer_weights > 0) {
 508         ideallocal = (uint32_t) (ident->localweight * ident->limit / total_weight);
 509     } else {
 510         ideallocal = ident->limit / (ident->comm.remote_node_count + 1);
 511     }
 512
 513     printlog(LOG_DEBUG, "%.3f ActualWeight\n", ident->localweight);
 514
 515     printlog(LOG_DEBUG, "%.3f %.3f %.3f %.3f  Under / Over / Actual / Rate\n",
 516             ideal_under / (ideal_under + peer_weights),
 517             ideal_over / (ideal_over + peer_weights),
 518             ident->localweight / (ident->localweight + peer_weights),
 519             (double) local_rate / (double) ident->limit);
 520
 521     printlog(LOG_DEBUG, "%.3f %.3f IdealUnd IdealOve\n",ideal_under,ideal_over);
 522
 523     if (system_loglevel == LOG_DEBUG) {
 524         printf("local_rate: %d, idealweight: %.3f, localweight: %.3f, total_weight: %.3f\n",
 525             local_rate, idealweight, ident->localweight, total_weight);
 526     }
 527
 528 #if 0
 529     if (printcounter <= 0) {
 530         struct timeval tv;
 531         double time_now;
 532
 533         gettimeofday(&tv, NULL);
 534         time_now = (double) tv.tv_sec + (double) ((double) tv.tv_usec / (double) 1000000);
 535
 536         printlog(LOG_WARN, "%.2f %d %.2f %.2f %.2f %d %d %d %d %d %d %d %d ", time_now, ftable->inst_rate,
 537             idealweight, ident->localweight, total_weight, ftable->num_flows, ftable->num_flows_5k,
 538             ftable->num_flows_10k, ftable->num_flows_20k, ftable->num_flows_50k, ftable->avg_rate,
 539             ftable->max_flow_rate, ftable->max_flow_rate_flow_hash);
 540
 541         printcounter = PRINT_COUNTER_RESET;
 542     } else {
 543         printcounter -= 1;
 544     }
 545
 546     //printf("Dampen: %d, dampen_increase: %d, peer_weights: %.3f, regime: %d\n",
 547     //       dampen, dampen_increase, peer_weights, regime);
 548
 549     if (regime == 3) {
 550         printlog(LOG_DEBUG, "MIN: min said to use flow counting, which was %.3f when other method said %.3f.\n",
 551                  ideal_over, ideal_under);
 552     }
 553     See print_statistics()
 554 #endif
 555
 556     printlog(LOG_DEBUG, "ideallocal is %d\n", ideallocal);
 557
 558     return(ideallocal);
 559 }
 560
 561 /**
 562  * Determines the local drop probability for a GRD identity every estimate
 563  * interval.
 564  */
 565 static double allocate_grd(identity_t *ident, double aggdemand) {
 566     double dropprob;
 567     double global_limit = (double) (ident->limit);
 568
 569     if (aggdemand > global_limit) {
 570         dropprob = (aggdemand-global_limit)/aggdemand;
 571     } else {
 572         dropprob = 0.0;
 573     }
 574
 575     if (system_loglevel == LOG_DEBUG) {
 576         printf("local rate: %d, aggregate demand: %.3f, drop prob: %.3f\n",
 577            ident->common.rate, aggdemand, dropprob);
 578     }
 579
 580     return dropprob;
 581 }
 582
 583 /**
 584  * Given current estimates of local rate (weight) and remote rates (weights)
 585  * use GRD or FPS to calculate a new local limit.
 586  */
 587 static void allocate(limiter_t *limiter, identity_t *ident) {
 588     /* Represents aggregate rate for GRD and aggregate weight for FPS. */
 589     double comm_val = 0;
 590
 591     /* Read comm_val from comm layer. */
 592     if (limiter->policy == POLICY_FPS) {
 593         read_comm(&ident->comm, &comm_val,
 594                 ident->total_weight / (double) (ident->comm.remote_node_count + 1));
 595     } else {
 596         read_comm(&ident->comm, &comm_val,
 597                 (double) (ident->limit / (double) (ident->comm.remote_node_count + 1)));
 598     }
 599     printlog(LOG_DEBUG, "%.3f Aggregate weight/rate (FPS/GRD)\n", comm_val);
 600
 601     /* Experimental printing. */
 602     printlog(LOG_DEBUG, "%.3f \t Kbps used rate. ID:%d\n",
 603              (double) ident->common.rate / (double) 128, ident->id);
 604     ident->avg_bytes += ident->common.rate;
 605
 606     if (limiter->policy == POLICY_FPS) {
 607 #ifdef SHADOW_ACCTING
 608
 609         allocate_fps_pretend(ident, comm_val, &ident->shadow_common, "SHADOW-ID");
 610
 611         ident->last_localweight_copy = ident->localweight_copy;
 612 #endif
 613
 614         ident->locallimit = allocate_fps(ident, comm_val, &ident->common, "ID");
 615         ident->last_localweight = ident->localweight;
 616
 617         /* Update other limiters with our weight by writing to comm layer. */
 618         write_local_value(&ident->comm, ident->localweight);
 619     } else {
 620         ident->locallimit = 0; /* Unused with GRD. */
 621         ident->last_drop_prob = ident->drop_prob;
 622         ident->drop_prob = allocate_grd(ident, comm_val);
 623
 624         /* Update other limiters with our rate by writing to comm layer. */
 625         write_local_value(&ident->comm, ident->common.rate);
 626     }
 627
 628     /* Update identity state. */
 629     ident->common.last_rate = ident->common.rate;
 630 }
 631
 632 /**
 633  * Traces all of the parent pointers of a leaf all the way to the root in
 634  * order to find the maximum drop probability in the chain.
 635  */
 636 static double find_leaf_drop_prob(leaf_t *leaf) {
 637     identity_t *current = leaf->parent;
 638     double result = 0;
 639
 640     assert(current);
 641
 642     while (current != NULL) {
 643         if (current->drop_prob > result) {
 644             result = current->drop_prob;
 645         }
 646         current = current->parent;
 647     }
 648
 649     return result;
 650 }
 651
 652 /**
 653  * This is called once per estimate interval to enforce the rate that allocate
 654  * has decided upon.  It makes calls to tc using system().
 655  */
 656 static void enforce(limiter_t *limiter, identity_t *ident) {
 657     char cmd[CMD_BUFFER_SIZE];
 658     int ret = 0;
 659     int i = 0;
 660
 661     switch (limiter->policy) {
 662         case POLICY_FPS:
 663
 664             /* TC treats limits of 0 (8bit) as unlimited, which causes the
 665              * entire rate limiting system to become unpredictable.  In
 666              * reality, we also don't want any limiter to be able to set its
 667              * limit so low that it chokes all of the flows to the point that
 668              * they can't increase.  Thus, when we're setting a low limit, we
 669              * make sure that it isn't too low by using the
 670              * FLOW_START_THRESHOLD. */
 671
 672             if (ident->locallimit < FLOW_START_THRESHOLD) {
 673                 ident->locallimit = FLOW_START_THRESHOLD;
 674             }
 675
 676             /* Do not allow the node to set a limit higher than its
 677              * administratively assigned upper limit (bwcap). */
 678             if (limiter->nodelimit != 0 && ident->locallimit > limiter->nodelimit) {
 679                 ident->locallimit = limiter->nodelimit;
 680             }
 681
 682             if (system_loglevel == LOG_DEBUG) {
 683                 printf("FPS: Setting local limit to %d\n", ident->locallimit);
 684             }
 685             printlog(LOG_DEBUG, "%d Limit ID:%d\n", ident->locallimit, ident->id);
 686
 687 #if 0
 688             if (printcounter == PRINT_COUNTER_RESET) {
 689                 if (ident->common.max_flow_rate > 0) {
 690                     printlog(LOG_WARN, "%d ID:%d %.3f\n", ident->locallimit, ident->id,
 691                              (double) ident->common.rate / (double) ident->common.max_flow_rate);
 692                 } else {
 693                     printlog(LOG_WARN, "%d ID:%d 0\n", ident->locallimit, ident->id);
 694                 }
 695             }
 696             This is now done in print_statistics()
 697 #endif
 698
 699             snprintf(cmd, CMD_BUFFER_SIZE,
 700                      "/sbin/tc class change dev eth0 parent 1:%x classid 1:%x htb rate 8bit ceil %dbps quantum 1600",
 701                      ident->htb_parent, ident->htb_node, ident->locallimit);
 702
 703             if (do_enforcement) {
 704                 ret = system(cmd);
 705
 706                 if (ret) {
 707                     /* FIXME: call failed.  What to do? */
 708                     printlog(LOG_CRITICAL, "***TC call failed? Call was: %s***\n", cmd);
 709                 }
 710             }
 711             break;
 712
 713         case POLICY_GRD:
 714             for (i = 0; i < ident->leaf_count; ++i) {
 715                 if (ident->drop_prob >= ident->leaves[i]->drop_prob) {
 716                     /* The new drop probability for this identity is greater
 717                      * than or equal to the leaf's current drop probability.
 718                      * We can safely use the larger value at this leaf
 719                      * immediately. */
 720                     ident->leaves[i]->drop_prob = ident->drop_prob;
 721                 } else if (ident->last_drop_prob < ident->leaves[i]->drop_prob) {
 722                     /* The old drop probability for this identity is less than
 723                      * the leaf's current drop probability.  This means that
 724                      * this identity couldn't have been the limiting ident,
 725                      * so nothing needs to be done because the old limiting
 726                      * ident is still the limiting factor. */
 727
 728                     /* Intentionally blank. */
 729                 } else {
 730                     /* If neither of the above are true, then...
 731                      * 1) The new drop probability for the identity is less
 732                      * than what it previously was, and
 733                      * 2) This ident may have had the maximum drop probability
 734                      * of all idents limiting this leaf, and therefore we need
 735                      * to follow the leaf's parents up to the root to find the
 736                      * new leaf drop probability safely. */
 737                     ident->leaves[i]->drop_prob =
 738                             find_leaf_drop_prob(ident->leaves[i]);
 739                 }
 740
 741                 /* Make the call to tc. */
 742 #ifdef DELAY40MS
 743                 snprintf(cmd, CMD_BUFFER_SIZE,
 744                          "/sbin/tc qdisc change dev eth0 parent 1:1%x handle 1%x netem loss %.4f delay 40ms",
 745                          ident->leaves[i]->xid, ident->leaves[i]->xid,
 746                          (100 * ident->leaves[i]->drop_prob));
 747 #else
 748                 snprintf(cmd, CMD_BUFFER_SIZE,
 749                          "/sbin/tc qdisc change dev eth0 parent 1:1%x handle 1%x netem loss %.4f delay 0ms",
 750                          ident->leaves[i]->xid, ident->leaves[i]->xid,
 751                          (100 * ident->leaves[i]->drop_prob));
 752 #endif
 753                 if (do_enforcement) {
 754                     ret = system(cmd);
 755
 756                     if (ret) {
 757                         /* FIXME: call failed.  What to do? */
 758                         printlog(LOG_CRITICAL, "***TC call failed?***\n");
 759                     }
 760                 }
 761             }
 762
 763             break;
 764
 765         default:
 766             printlog(LOG_CRITICAL, "DRL enforce: unknown policy %d\n",limiter->policy);
 767             break;
 768     }
 769
 770     return;
 771 }
 772
 773 /**
 774  * This function is periodically called to clean the stable instance's flow
 775  * accounting tables for each identity.
 776  */
 777 static void clean(drl_instance_t *instance) {
 778     identity_t *ident = NULL;
 779
 780     map_reset_iterate(instance->ident_map);
 781     while ((ident = map_next(instance->ident_map)) != NULL) {
 782         pthread_mutex_lock(&ident->table_mutex);
 783
 784         ident->table_cleanup_function(ident->table);
 785
 786 #ifdef SHADOW_ACCTING
 787
 788         standard_table_cleanup((standard_flow_table) ident->shadow_table);
 789
 790 #endif
 791
 792         pthread_mutex_unlock(&ident->table_mutex);
 793     }
 794
 795     /* Periodically flush the log file. */
 796     flushlog();
 797 }
 798
 799 static void print_averages(drl_instance_t *instance, int print_interval) {
 800     identity_t *ident = NULL;
 801
 802     map_reset_iterate(instance->ident_map);
 803     while ((ident = map_next(instance->ident_map)) != NULL) {
 804         ident->avg_bytes /= (double) print_interval;
 805         //printf("avg_bytes = %f, print_interval = %d\n", ident->avg_bytes, print_interval);
 806         printlog(LOG_DEBUG, "%.3f \t Avg rate. ID:%d\n",
 807                  ident->avg_bytes / 128, ident->id);
 808         //printf("%.3f \t Avg rate. ID:%d\n",
 809         //         ident->avg_bytes / 128, ident->id);
 810         ident->avg_bytes = 0;
 811     }
 812 }
 813
 814 /** Thread function to handle local rate estimation.
 815  *
 816  * None of our simple hashmap functions are thread safe, so we lock the limiter
 817  * with an rwlock to prevent another thread from attempting to modify the set
 818  * of identities.
 819  *
 820  * Each identity also has a private lock for its table.  This gets locked by
 821  * table-modifying functions such as estimate and clean. It's also locked in
 822  * ulogd_DRL.c when the table is being updated with new packets.
 823  */
 824 void handle_estimation(void *arg) {
 825     limiter_t *limiter = (limiter_t *) arg;
 826     int clean_timer, clean_wait_intervals;
 827     useconds_t sleep_time = limiter->estintms * 1000;
 828     uint32_t cal_slot = 0;
 829     int print_interval = 1000 / (limiter->estintms);
 830
 831     sigset_t signal_mask;
 832
 833     sigemptyset(&signal_mask);
 834     sigaddset(&signal_mask, SIGHUP);
 835     sigaddset(&signal_mask, SIGUSR1);
 836     sigaddset(&signal_mask, SIGUSR2);
 837     pthread_sigmask(SIG_BLOCK, &signal_mask, NULL);
 838
 839     /* Determine the number of intervals we should wait before hitting the
 840      * specified clean interval. (Converts seconds -> intervals). */
 841     clean_wait_intervals = IDENT_CLEAN_INTERVAL * (1000.0 / limiter->estintms);
 842     clean_timer = clean_wait_intervals;
 843
 844     while (true) {
 845         printlog(LOG_DEBUG, "--Beginning new tick.--\n");
 846
 847         /* Sleep according to the delay of the estimate interval. */
 848         usleep(sleep_time);
 849
 850         /* Grab the limiter lock for reading.  This prevents identities from
 851          * disappearing beneath our feet. */
 852         pthread_rwlock_rdlock(&limiter->limiter_lock);
 853
 854         cal_slot = limiter->stable_instance.cal_slot & SCHEDMASK;
 855
 856         /* Service all the identities that are scheduled to run during this
 857          * tick. */
 858         while (!TAILQ_EMPTY(limiter->stable_instance.cal + cal_slot)) {
 859             identity_action *iaction = TAILQ_FIRST(limiter->stable_instance.cal + cal_slot);
 860             TAILQ_REMOVE(limiter->stable_instance.cal + cal_slot, iaction, calendar);
 861
 862             /* Only execute the action if it is valid. */
 863             if (iaction->valid == 0) {
 864                 free(iaction);
 865                 continue;
 866             }
 867
 868             switch (iaction->action) {
 869                 case ACTION_MAINLOOP:
 870
 871                     printlog(LOG_DEBUG, "Main loop: identity %d\n", iaction->ident->id);
 872
 873                     /* Update the ident's flow accouting table with the latest info. */
 874                     estimate(iaction->ident, limiter->estintms);
 875
 876                     /* Determine its share of the rate allocation. */
 877                     allocate(limiter, iaction->ident);
 878
 879                     /* Make tc calls to enforce the rate we decided upon. */
 880                     enforce(limiter, iaction->ident);
 881
 882                     /* Add ident back to the queue at a future time slot. */
 883                     TAILQ_INSERT_TAIL(limiter->stable_instance.cal +
 884                             ((cal_slot + iaction->ident->mainloop_intervals) & SCHEDMASK),
 885                             iaction, calendar);
 886                     break;
 887
 888                 case ACTION_COMMUNICATE:
 889
 890                     printlog(LOG_DEBUG, "Communicating: identity %d\n", iaction->ident->id);
 891
 892                     /* Tell the comm library to propagate this identity's result for
 893                      * this interval.*/
 894                     send_update(&iaction->ident->comm, iaction->ident->id);
 895
 896                     /* Add ident back to the queue at a future time slot. */
 897                     TAILQ_INSERT_TAIL(limiter->stable_instance.cal +
 898                             ((cal_slot + iaction->ident->communication_intervals) & SCHEDMASK),
 899                             iaction, calendar);
 900                 break;
 901
 902                 default:
 903                     printlog(LOG_CRITICAL, "Unknown identity action!?!\n");
 904                     exit(EXIT_FAILURE);
 905             }
 906         }
 907
 908         print_interval--;
 909         if (loglevel() == LOG_DEBUG && print_interval <= 0) {
 910             print_interval = 1000 / (limiter->estintms);
 911             print_averages(&limiter->stable_instance, print_interval);
 912         }
 913
 914         /* Check if enough intervals have passed for cleaning. */
 915         if (clean_timer <= 0) {
 916             clean(&limiter->stable_instance);
 917             clean_timer = clean_wait_intervals;
 918         } else {
 919             clean_timer--;
 920         }
 921
 922         limiter->stable_instance.cal_slot += 1;
 923
 924         pthread_rwlock_unlock(&limiter->limiter_lock);
 925     }
 926 }