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   1 /*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
   2  *
   3  *  Libmemcached library
   4  *
   5  *  Copyright (C) 2011 Data Differential, http://datadifferential.com/
   6  *  Copyright (C) 2006-2010 Brian Aker All rights reserved.
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions are
  10  *  met:
  11  *
  12  *      * Redistributions of source code must retain the above copyright
  13  *  notice, this list of conditions and the following disclaimer.
  14  *
  15  *      * Redistributions in binary form must reproduce the above
  16  *  copyright notice, this list of conditions and the following disclaimer
  17  *  in the documentation and/or other materials provided with the
  18  *  distribution.
  19  *
  20  *      * The names of its contributors may not be used to endorse or
  21  *  promote products derived from this software without specific prior
  22  *  written permission.
  23  *
  24  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  25  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  26  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  27  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  28  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  30  *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  34  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  */
  37
  38 #include <libmemcached/common.h>
  39
  40 #include <cmath>
  41 #include <sys/time.h>
  42
  43 /* Protoypes (static) */
  44 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
  45                                      in_port_t port,
  46                                      uint32_t weight,
  47                                      memcached_connection_t type);
  48
  49 static memcached_return_t update_continuum(memcached_st *ptr);
  50
  51 static int compare_servers(const void *p1, const void *p2)
  52 {
  53   int return_value;
  54   memcached_server_instance_st a= (memcached_server_instance_st)p1;
  55   memcached_server_instance_st b= (memcached_server_instance_st)p2;
  56
  57   return_value= strcmp(a->hostname, b->hostname);
  58
  59   if (return_value == 0)
  60   {
  61     return_value= (int) (a->port - b->port);
  62   }
  63
  64   return return_value;
  65 }
  66
  67 static void sort_hosts(memcached_st *ptr)
  68 {
  69   if (memcached_server_count(ptr))
  70   {
  71     memcached_server_write_instance_st instance;
  72
  73     qsort(memcached_server_list(ptr), memcached_server_count(ptr), sizeof(memcached_server_st), compare_servers);
  74     instance= memcached_server_instance_fetch(ptr, 0);
  75     instance->number_of_hosts= memcached_server_count(ptr);
  76   }
  77 }
  78
  79
  80 memcached_return_t run_distribution(memcached_st *ptr)
  81 {
  82   if (ptr->flags.use_sort_hosts)
  83     sort_hosts(ptr);
  84
  85   switch (ptr->distribution)
  86   {
  87   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  88   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  89   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
  90   case MEMCACHED_DISTRIBUTION_CONSISTENT_WEIGHTED:
  91     return update_continuum(ptr);
  92   case MEMCACHED_DISTRIBUTION_VIRTUAL_BUCKET:
  93   case MEMCACHED_DISTRIBUTION_MODULA:
  94     break;
  95   case MEMCACHED_DISTRIBUTION_RANDOM:
  96     srandom((uint32_t) time(NULL));
  97     break;
  98   case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
  99   default:
 100     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
 101   }
 102
 103   return MEMCACHED_SUCCESS;
 104 }
 105
 106 static uint32_t ketama_server_hash(const char *key, size_t key_length, uint32_t alignment)
 107 {
 108   unsigned char results[16];
 109
 110   libhashkit_md5_signature((unsigned char*)key, key_length, results);
 111
 112   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
 113     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
 114     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
 115     | (results[0 + alignment * 4] & 0xFF);
 116 }
 117
 118 static int continuum_item_cmp(const void *t1, const void *t2)
 119 {
 120   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
 121   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
 122
 123   /* Why 153? Hmmm... */
 124   WATCHPOINT_ASSERT(ct1->value != 153);
 125   if (ct1->value == ct2->value)
 126     return 0;
 127   else if (ct1->value > ct2->value)
 128     return 1;
 129   else
 130     return -1;
 131 }
 132
 133 static memcached_return_t update_continuum(memcached_st *ptr)
 134 {
 135   uint32_t continuum_index= 0;
 136   memcached_server_st *list;
 137   uint32_t pointer_counter= 0;
 138   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 139   uint32_t pointer_per_hash= 1;
 140   uint32_t live_servers= 0;
 141   struct timeval now;
 142
 143   if (gettimeofday(&now, NULL))
 144   {
 145     return memcached_set_errno(*ptr, errno, MEMCACHED_AT);
 146   }
 147
 148   list= memcached_server_list(ptr);
 149
 150   /* count live servers (those without a retry delay set) */
 151   bool is_auto_ejecting= _is_auto_eject_host(ptr);
 152   if (is_auto_ejecting)
 153   {
 154     live_servers= 0;
 155     ptr->ketama.next_distribution_rebuild= 0;
 156     for (uint32_t host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 157     {
 158       if (list[host_index].next_retry <= now.tv_sec)
 159       {
 160         live_servers++;
 161       }
 162       else
 163       {
 164         if (ptr->ketama.next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->ketama.next_distribution_rebuild)
 165         {
 166           ptr->ketama.next_distribution_rebuild= list[host_index].next_retry;
 167         }
 168       }
 169     }
 170   }
 171   else
 172   {
 173     live_servers= memcached_server_count(ptr);
 174   }
 175
 176   uint64_t is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 177   uint32_t points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 178
 179   if (not live_servers)
 180   {
 181     return MEMCACHED_SUCCESS;
 182   }
 183
 184   if (live_servers > ptr->ketama.continuum_count)
 185   {
 186     memcached_continuum_item_st *new_ptr;
 187
 188     new_ptr= static_cast<memcached_continuum_item_st*>(libmemcached_realloc(ptr, ptr->ketama.continuum,
 189                                                                             sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server));
 190
 191     if (new_ptr == 0)
 192       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 193
 194     ptr->ketama.continuum= new_ptr;
 195     ptr->ketama.continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 196   }
 197
 198   uint64_t total_weight= 0;
 199   if (is_ketama_weighted)
 200   {
 201     for (uint32_t host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 202     {
 203       if (! is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 204       {
 205         total_weight += list[host_index].weight;
 206       }
 207     }
 208   }
 209
 210   for (uint32_t host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 211   {
 212     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 213       continue;
 214
 215     if (is_ketama_weighted)
 216     {
 217         float pct = (float)list[host_index].weight / (float)total_weight;
 218         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 219         pointer_per_hash= 4;
 220 #ifdef DEBUG
 221         printf("ketama_weighted:%s|%d|%llu|%u\n",
 222                list[host_index].hostname,
 223                list[host_index].port,
 224                (unsigned long long)list[host_index].weight,
 225                pointer_per_server);
 226 #endif
 227     }
 228
 229
 230     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 231     {
 232       for (uint32_t pointer_index= 0;
 233            pointer_index < pointer_per_server / pointer_per_hash;
 234            pointer_index++)
 235       {
 236         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 237         int sort_host_length;
 238
 239         // Spymemcached ketema key format is: hostname/ip:port-index
 240         // If hostname is not available then: /ip:port-index
 241         sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 242                                    "/%s:%u-%u",
 243                                    list[host_index].hostname,
 244                                    (uint32_t)list[host_index].port,
 245                                    pointer_index);
 246
 247         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 248         {
 249           return MEMCACHED_FAILURE;
 250         }
 251 #ifdef DEBUG
 252         printf("update_continuum: key is %s\n", sort_host);
 253 #endif
 254
 255         WATCHPOINT_ASSERT(sort_host_length);
 256
 257         if (is_ketama_weighted)
 258         {
 259           for (uint32_t x= 0; x < pointer_per_hash; x++)
 260           {
 261             uint32_t value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 262             ptr->ketama.continuum[continuum_index].index= host_index;
 263             ptr->ketama.continuum[continuum_index++].value= value;
 264           }
 265         }
 266         else
 267         {
 268           uint32_t value= hashkit_digest(&ptr->hashkit, sort_host, (size_t)sort_host_length);
 269           ptr->ketama.continuum[continuum_index].index= host_index;
 270           ptr->ketama.continuum[continuum_index++].value= value;
 271         }
 272       }
 273     }
 274     else
 275     {
 276       for (uint32_t pointer_index= 1;
 277            pointer_index <= pointer_per_server / pointer_per_hash;
 278            pointer_index++)
 279       {
 280         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 281         int sort_host_length;
 282
 283         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 284         {
 285           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 286                                      "%s-%u",
 287                                      list[host_index].hostname,
 288                                      pointer_index - 1);
 289         }
 290         else
 291         {
 292           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 293                                      "%s:%u-%u",
 294                                      list[host_index].hostname,
 295                                      (uint32_t)list[host_index].port,
 296                                      pointer_index - 1);
 297         }
 298
 299         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 300         {
 301           return MEMCACHED_FAILURE;
 302         }
 303
 304         WATCHPOINT_ASSERT(sort_host_length);
 305
 306         if (is_ketama_weighted)
 307         {
 308           for (uint32_t x = 0; x < pointer_per_hash; x++)
 309           {
 310             uint32_t value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 311             ptr->ketama.continuum[continuum_index].index= host_index;
 312             ptr->ketama.continuum[continuum_index++].value= value;
 313           }
 314         }
 315         else
 316         {
 317           uint32_t value= hashkit_digest(&ptr->hashkit, sort_host, (size_t)sort_host_length);
 318           ptr->ketama.continuum[continuum_index].index= host_index;
 319           ptr->ketama.continuum[continuum_index++].value= value;
 320         }
 321       }
 322     }
 323
 324     pointer_counter+= pointer_per_server;
 325   }
 326
 327   WATCHPOINT_ASSERT(ptr);
 328   WATCHPOINT_ASSERT(ptr->ketama.continuum);
 329   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 330   ptr->ketama.continuum_points_counter= pointer_counter;
 331   qsort(ptr->ketama.continuum, ptr->ketama.continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 332
 333 #ifdef DEBUG
 334   for (uint32_t pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 335   {
 336     WATCHPOINT_ASSERT(ptr->ketama.continuum[pointer_index].value <= ptr->ketama.continuum[pointer_index + 1].value);
 337   }
 338 #endif
 339
 340   return MEMCACHED_SUCCESS;
 341 }
 342
 343
 344 memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_list_st list)
 345 {
 346   if (not list)
 347     return MEMCACHED_SUCCESS;
 348
 349   uint32_t count= memcached_server_list_count(list);
 350
 351   memcached_server_st *new_host_list;
 352   new_host_list= static_cast<memcached_server_st*>(libmemcached_realloc(ptr, memcached_server_list(ptr),
 353                                                                         sizeof(memcached_server_st) * (count + memcached_server_count(ptr))));
 354
 355   if (not new_host_list)
 356     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 357
 358   memcached_server_list_set(ptr, new_host_list);
 359
 360   for (uint32_t x= 0; x < count; x++)
 361   {
 362     memcached_server_write_instance_st instance;
 363
 364     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 365         or ((list[x].type == MEMCACHED_CONNECTION_UDP)
 366             and ! (ptr->flags.use_udp)) )
 367     {
 368       return MEMCACHED_INVALID_HOST_PROTOCOL;
 369     }
 370
 371     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 372
 373     // We have extended the array, and now we will find it, and use it.
 374     instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 375     WATCHPOINT_ASSERT(instance);
 376
 377     if (not memcached_server_create_with(ptr, instance, list[x].hostname,
 378                                          list[x].port, list[x].weight, list[x].type))
 379     {
 380       return memcached_set_error(*ptr, MEMCACHED_MEMORY_ALLOCATION_FAILURE, MEMCACHED_AT);
 381     }
 382
 383     if (list[x].weight > 1)
 384     {
 385       ptr->ketama.weighted= true;
 386     }
 387
 388     ptr->number_of_hosts++;
 389   }
 390
 391   // Provides backwards compatibility with server list.
 392   {
 393     memcached_server_write_instance_st instance;
 394     instance= memcached_server_instance_fetch(ptr, 0);
 395     instance->number_of_hosts= memcached_server_count(ptr);
 396   }
 397
 398   return run_distribution(ptr);
 399 }
 400
 401 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 402                                                     const char *filename)
 403 {
 404   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 405 }
 406
 407 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 408                                                                 const char *filename,
 409                                                                 uint32_t weight)
 410 {
 411   if (! filename)
 412     return MEMCACHED_FAILURE;
 413
 414   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 415 }
 416
 417 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 418                                             const char *hostname,
 419                                             in_port_t port)
 420 {
 421   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 422 }
 423
 424 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 425                                                         const char *hostname,
 426                                                         in_port_t port,
 427                                                         uint32_t weight)
 428 {
 429   if (not port)
 430     port= MEMCACHED_DEFAULT_PORT;
 431
 432   if (not hostname)
 433     hostname= "localhost";
 434
 435   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 436 }
 437
 438 memcached_return_t memcached_server_add(memcached_st *ptr,
 439                                         const char *hostname,
 440                                         in_port_t port)
 441 {
 442   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 443 }
 444
 445 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 446                                                     const char *hostname,
 447                                                     in_port_t port,
 448                                                     uint32_t weight)
 449 {
 450   if (not port)
 451     port= MEMCACHED_DEFAULT_PORT;
 452
 453   if (not hostname)
 454     hostname= "localhost";
 455
 456   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 457 }
 458
 459 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 460                                      in_port_t port,
 461                                      uint32_t weight,
 462                                      memcached_connection_t type)
 463 {
 464
 465   if ( (ptr->flags.use_udp and type != MEMCACHED_CONNECTION_UDP)
 466       or ( (type == MEMCACHED_CONNECTION_UDP) and (not ptr->flags.use_udp) ) )
 467   {
 468     return MEMCACHED_INVALID_HOST_PROTOCOL;
 469   }
 470
 471   memcached_server_st *new_host_list= static_cast<memcached_server_st*>(libmemcached_realloc(ptr, memcached_server_list(ptr),
 472                                                                                              sizeof(memcached_server_st) * (ptr->number_of_hosts + 1)));
 473
 474   if (not new_host_list)
 475     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 476
 477   memcached_server_list_set(ptr, new_host_list);
 478
 479   /* TODO: Check return type */
 480   memcached_server_write_instance_st instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 481
 482   if (not memcached_server_create_with(ptr, instance, hostname, port, weight, type))
 483   {
 484     return memcached_set_error(*ptr, MEMCACHED_MEMORY_ALLOCATION_FAILURE, MEMCACHED_AT);
 485   }
 486
 487   if (weight > 1)
 488   {
 489     ptr->ketama.weighted= true;
 490   }
 491
 492   ptr->number_of_hosts++;
 493
 494   // @note we place the count in the bottom of the server list
 495   instance= memcached_server_instance_fetch(ptr, 0);
 496   memcached_servers_set_count(instance, memcached_server_count(ptr));
 497
 498   return run_distribution(ptr);
 499 }
 500
 501 memcached_return_t memcached_server_add_parsed(memcached_st *ptr,
 502                                                const char *hostname,
 503                                                size_t hostname_length,
 504                                                in_port_t port,
 505                                                uint32_t weight)
 506 {
 507   char buffer[NI_MAXHOST];
 508
 509   memcpy(buffer, hostname, hostname_length);
 510   buffer[hostname_length]= 0;
 511
 512   return server_add(ptr, buffer,
 513                     port,
 514                     weight,
 515                     MEMCACHED_CONNECTION_TCP);
 516 }