git.m6w6.name Git - m6w6/libmemcached/blob - libmemcached/hosts.c

   1 #include "common.h"
   2 #include <math.h>
   3
   4 /* Protoypes (static) */
   5 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
   6                                      in_port_t port,
   7                                      uint32_t weight,
   8                                      memcached_connection_t type);
   9 memcached_return_t update_continuum(memcached_st *ptr);
  10
  11 static int compare_servers(const void *p1, const void *p2)
  12 {
  13   int return_value;
  14   memcached_server_st *a= (memcached_server_st *)p1;
  15   memcached_server_st *b= (memcached_server_st *)p2;
  16
  17   return_value= strcmp(a->hostname, b->hostname);
  18
  19   if (return_value == 0)
  20   {
  21     return_value= (int) (a->port - b->port);
  22   }
  23
  24   return return_value;
  25 }
  26
  27 static void sort_hosts(memcached_st *ptr)
  28 {
  29   if (ptr->number_of_hosts)
  30   {
  31     qsort(ptr->hosts, ptr->number_of_hosts, sizeof(memcached_server_st), compare_servers);
  32     ptr->hosts[0].count= (uint16_t) ptr->number_of_hosts;
  33   }
  34 }
  35
  36
  37 memcached_return_t run_distribution(memcached_st *ptr)
  38 {
  39   switch (ptr->distribution)
  40   {
  41   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  42   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  43   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
  44     return update_continuum(ptr);
  45   case MEMCACHED_DISTRIBUTION_MODULA:
  46     if (ptr->flags.use_sort_hosts)
  47       sort_hosts(ptr);
  48     break;
  49   case MEMCACHED_DISTRIBUTION_RANDOM:
  50     srandom((uint32_t) time(NULL));
  51     break;
  52   case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
  53   default:
  54     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  55   }
  56
  57   ptr->last_disconnected_server = NULL;
  58
  59   return MEMCACHED_SUCCESS;
  60 }
  61
  62 void server_list_free(memcached_st *ptr, memcached_server_st *servers)
  63 {
  64   unsigned int x;
  65
  66   if (servers == NULL)
  67     return;
  68
  69   for (x= 0; x < servers->count; x++)
  70     if (servers[x].address_info)
  71     {
  72       freeaddrinfo(servers[x].address_info);
  73       servers[x].address_info= NULL;
  74     }
  75
  76   if (ptr)
  77     ptr->call_free(ptr, servers);
  78   else
  79     free(servers);
  80 }
  81
  82 static uint32_t ketama_server_hash(const char *key, unsigned int key_length, int alignment)
  83 {
  84   unsigned char results[16];
  85
  86   md5_signature((unsigned char*)key, key_length, results);
  87   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  88     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
  89     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
  90     | (results[0 + alignment * 4] & 0xFF);
  91 }
  92
  93 static int continuum_item_cmp(const void *t1, const void *t2)
  94 {
  95   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  96   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
  97
  98   /* Why 153? Hmmm... */
  99   WATCHPOINT_ASSERT(ct1->value != 153);
 100   if (ct1->value == ct2->value)
 101     return 0;
 102   else if (ct1->value > ct2->value)
 103     return 1;
 104   else
 105     return -1;
 106 }
 107
 108 memcached_return_t update_continuum(memcached_st *ptr)
 109 {
 110   uint32_t host_index;
 111   uint32_t continuum_index= 0;
 112   uint32_t value;
 113   memcached_server_st *list;
 114   uint32_t pointer_index;
 115   uint32_t pointer_counter= 0;
 116   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 117   uint32_t pointer_per_hash= 1;
 118   uint64_t total_weight= 0;
 119   uint64_t is_ketama_weighted= 0;
 120   uint64_t is_auto_ejecting= 0;
 121   uint32_t points_per_server= 0;
 122   uint32_t live_servers= 0;
 123   struct timeval now;
 124
 125   if (gettimeofday(&now, NULL) != 0)
 126   {
 127     ptr->cached_errno = errno;
 128     return MEMCACHED_ERRNO;
 129   }
 130
 131   list = ptr->hosts;
 132
 133   /* count live servers (those without a retry delay set) */
 134   is_auto_ejecting= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS);
 135   if (is_auto_ejecting)
 136   {
 137     live_servers= 0;
 138     ptr->next_distribution_rebuild= 0;
 139     for (host_index= 0; host_index < ptr->number_of_hosts; ++host_index)
 140     {
 141       if (list[host_index].next_retry <= now.tv_sec)
 142         live_servers++;
 143       else
 144       {
 145         if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
 146           ptr->next_distribution_rebuild= list[host_index].next_retry;
 147       }
 148     }
 149   }
 150   else
 151     live_servers= ptr->number_of_hosts;
 152
 153   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 154   points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 155
 156   if (live_servers == 0)
 157     return MEMCACHED_SUCCESS;
 158
 159   if (live_servers > ptr->continuum_count)
 160   {
 161     memcached_continuum_item_st *new_ptr;
 162
 163     new_ptr= ptr->call_realloc(ptr, ptr->continuum,
 164                                sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 165
 166     if (new_ptr == 0)
 167       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 168
 169     ptr->continuum= new_ptr;
 170     ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 171   }
 172
 173   if (is_ketama_weighted)
 174   {
 175     for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 176     {
 177       if (list[host_index].weight == 0)
 178       {
 179         list[host_index].weight = 1;
 180       }
 181       if (!is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 182         total_weight += list[host_index].weight;
 183     }
 184   }
 185
 186   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 187   {
 188     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 189       continue;
 190
 191     if (is_ketama_weighted)
 192     {
 193         float pct = (float)list[host_index].weight / (float)total_weight;
 194         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 195         pointer_per_hash= 4;
 196 #ifdef DEBUG
 197         printf("ketama_weighted:%s|%d|%llu|%u\n",
 198                list[host_index].hostname,
 199                list[host_index].port,
 200                (unsigned long long)list[host_index].weight,
 201                pointer_per_server);
 202 #endif
 203     }
 204
 205
 206     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 207     {
 208       for (pointer_index= 0;
 209            pointer_index < pointer_per_server / pointer_per_hash;
 210            pointer_index++)
 211       {
 212         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 213         size_t sort_host_length;
 214
 215         // Spymemcached ketema key format is: hostname/ip:port-index
 216         // If hostname is not available then: /ip:port-index
 217         sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 218                                             "/%s:%d-%d",
 219                                             list[host_index].hostname,
 220                                             list[host_index].port,
 221                                             pointer_index);
 222 #ifdef DEBUG
 223         printf("update_continuum: key is %s\n", sort_host);
 224 #endif
 225
 226         WATCHPOINT_ASSERT(sort_host_length);
 227
 228         if (is_ketama_weighted)
 229         {
 230           unsigned int i;
 231           for (i = 0; i < pointer_per_hash; i++)
 232           {
 233              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
 234              ptr->continuum[continuum_index].index= host_index;
 235              ptr->continuum[continuum_index++].value= value;
 236           }
 237         }
 238         else
 239         {
 240           value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->distribution_hash);
 241           ptr->continuum[continuum_index].index= host_index;
 242           ptr->continuum[continuum_index++].value= value;
 243         }
 244       }
 245     }
 246     else
 247     {
 248       for (pointer_index= 1;
 249            pointer_index <= pointer_per_server / pointer_per_hash;
 250            pointer_index++)
 251       {
 252         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 253         size_t sort_host_length;
 254
 255         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 256         {
 257           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 258                                               "%s-%d",
 259                                               list[host_index].hostname,
 260                                               pointer_index - 1);
 261         }
 262         else
 263         {
 264           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 265                                               "%s:%d-%d",
 266                                               list[host_index].hostname,
 267                                               list[host_index].port, pointer_index - 1);
 268         }
 269
 270         WATCHPOINT_ASSERT(sort_host_length);
 271
 272         if (is_ketama_weighted)
 273         {
 274           unsigned int i;
 275           for (i = 0; i < pointer_per_hash; i++)
 276           {
 277              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
 278              ptr->continuum[continuum_index].index= host_index;
 279              ptr->continuum[continuum_index++].value= value;
 280           }
 281         }
 282         else
 283         {
 284           value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->distribution_hash);
 285           ptr->continuum[continuum_index].index= host_index;
 286           ptr->continuum[continuum_index++].value= value;
 287         }
 288       }
 289     }
 290
 291     pointer_counter+= pointer_per_server;
 292   }
 293
 294   WATCHPOINT_ASSERT(ptr);
 295   WATCHPOINT_ASSERT(ptr->continuum);
 296   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 297   ptr->continuum_points_counter= pointer_counter;
 298   qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 299
 300 #ifdef DEBUG
 301   for (pointer_index= 0; ptr->number_of_hosts && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 302   {
 303     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 304   }
 305 #endif
 306
 307   return MEMCACHED_SUCCESS;
 308 }
 309
 310
 311 memcached_return_t memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 312 {
 313   unsigned int x;
 314   uint16_t count;
 315   memcached_server_st *new_host_list;
 316
 317   if (!list)
 318     return MEMCACHED_SUCCESS;
 319
 320   count= list[0].count;
 321   new_host_list= ptr->call_realloc(ptr, ptr->hosts,
 322                                    sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 323
 324   if (!new_host_list)
 325     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 326
 327   ptr->hosts= new_host_list;
 328
 329   for (x= 0; x < count; x++)
 330   {
 331     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 332             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 333             && ! (ptr->flags.use_udp)) )
 334       return MEMCACHED_INVALID_HOST_PROTOCOL;
 335
 336     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 337     memcached_server_create(ptr, &ptr->hosts[ptr->number_of_hosts]);
 338     /* TODO check return type */
 339     (void)memcached_server_create_with(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 340                                        list[x].port, list[x].weight, list[x].type);
 341     ptr->number_of_hosts++;
 342   }
 343   ptr->hosts[0].count= (uint16_t) ptr->number_of_hosts;
 344
 345   return run_distribution(ptr);
 346 }
 347
 348 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 349                                                     const char *filename)
 350 {
 351   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 352 }
 353
 354 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 355                                                                 const char *filename,
 356                                                                 uint32_t weight)
 357 {
 358   if (!filename)
 359     return MEMCACHED_FAILURE;
 360
 361   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 362 }
 363
 364 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 365                                             const char *hostname,
 366                                             in_port_t port)
 367 {
 368   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 369 }
 370
 371 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 372                                                         const char *hostname,
 373                                                         in_port_t port,
 374                                                         uint32_t weight)
 375 {
 376   if (!port)
 377     port= MEMCACHED_DEFAULT_PORT;
 378
 379   if (!hostname)
 380     hostname= "localhost";
 381
 382   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 383 }
 384
 385 memcached_return_t memcached_server_add(memcached_st *ptr,
 386                                         const char *hostname,
 387                                         in_port_t port)
 388 {
 389   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 390 }
 391
 392 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 393                                                     const char *hostname,
 394                                                     in_port_t port,
 395                                                     uint32_t weight)
 396 {
 397   if (!port)
 398     port= MEMCACHED_DEFAULT_PORT;
 399
 400   if (!hostname)
 401     hostname= "localhost";
 402
 403   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 404 }
 405
 406 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 407                                      in_port_t port,
 408                                      uint32_t weight,
 409                                      memcached_connection_t type)
 410 {
 411   memcached_server_st *new_host_list;
 412
 413   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 414       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 415     return MEMCACHED_INVALID_HOST_PROTOCOL;
 416
 417   new_host_list= ptr->call_realloc(ptr, ptr->hosts,
 418                                    sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 419
 420   if (new_host_list == NULL)
 421     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 422
 423   ptr->hosts= new_host_list;
 424
 425   /* TODO: Check return type */
 426   (void)memcached_server_create_with(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, weight, type);
 427   ptr->number_of_hosts++;
 428   ptr->hosts[0].count= (uint16_t) ptr->number_of_hosts;
 429
 430   return run_distribution(ptr);
 431 }
 432
 433 memcached_return_t memcached_server_remove(memcached_server_st *st_ptr)
 434 {
 435   uint32_t x, host_index;
 436   memcached_st *ptr= st_ptr->root;
 437   memcached_server_st *list= ptr->hosts;
 438
 439   for (x= 0, host_index= 0; x < ptr->number_of_hosts; x++)
 440   {
 441     if (strncmp(list[x].hostname, st_ptr->hostname, MEMCACHED_MAX_HOST_LENGTH) != 0 || list[x].port != st_ptr->port)
 442     {
 443       if (host_index != x)
 444         memcpy(list+host_index, list+x, sizeof(memcached_server_st));
 445       host_index++;
 446     }
 447   }
 448   ptr->number_of_hosts= host_index;
 449
 450   if (st_ptr->address_info)
 451   {
 452     freeaddrinfo(st_ptr->address_info);
 453     st_ptr->address_info= NULL;
 454   }
 455   run_distribution(ptr);
 456
 457   return MEMCACHED_SUCCESS;
 458 }
 459
 460 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 461                                                   const char *hostname, in_port_t port,
 462                                                   memcached_return_t *error)
 463 {
 464   return memcached_server_list_append_with_weight(ptr, hostname, port, 0, error);
 465 }
 466
 467 memcached_server_st *memcached_server_list_append_with_weight(memcached_server_st *ptr,
 468                                                               const char *hostname, in_port_t port,
 469                                                               uint32_t weight,
 470                                                               memcached_return_t *error)
 471 {
 472   unsigned int count;
 473   memcached_server_st *new_host_list;
 474
 475   if (hostname == NULL || error == NULL)
 476     return NULL;
 477
 478   if (!port)
 479     port= MEMCACHED_DEFAULT_PORT;
 480
 481   /* Increment count for hosts */
 482   count= 1;
 483   if (ptr != NULL)
 484   {
 485     count+= ptr[0].count;
 486   }
 487
 488   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 489   if (!new_host_list)
 490   {
 491     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 492     return NULL;
 493   }
 494
 495   /* TODO: Check return type */
 496   memcached_server_create_with(NULL, &new_host_list[count-1], hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 497
 498   /* Backwards compatibility hack */
 499   new_host_list[0].count= (uint16_t) count;
 500
 501   *error= MEMCACHED_SUCCESS;
 502   return new_host_list;
 503 }
 504
 505 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 506 {
 507   if (ptr == NULL)
 508     return 0;
 509
 510   return ptr[0].count;
 511 }
 512
 513 void memcached_server_list_free(memcached_server_st *ptr)
 514 {
 515   server_list_free(NULL, ptr);
 516 }