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 static 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   if (ptr->flags.use_sort_hosts)
  40     sort_hosts(ptr);
  41
  42   switch (ptr->distribution)
  43   {
  44   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  45   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  46   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
  47     return update_continuum(ptr);
  48   case MEMCACHED_DISTRIBUTION_MODULA:
  49     break;
  50   case MEMCACHED_DISTRIBUTION_RANDOM:
  51     srandom((uint32_t) time(NULL));
  52     break;
  53   case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
  54   default:
  55     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  56   }
  57
  58   ptr->last_disconnected_server = NULL;
  59
  60   return MEMCACHED_SUCCESS;
  61 }
  62
  63 void server_list_free(memcached_st *ptr, memcached_server_st *servers)
  64 {
  65   unsigned int x;
  66
  67   if (servers == NULL)
  68     return;
  69
  70   for (x= 0; x < servers->count; x++)
  71     if (servers[x].address_info)
  72     {
  73       freeaddrinfo(servers[x].address_info);
  74       servers[x].address_info= NULL;
  75     }
  76
  77   if (ptr)
  78     ptr->call_free(ptr, servers);
  79   else
  80     free(servers);
  81 }
  82
  83 static uint32_t ketama_server_hash(const char *key, unsigned int key_length, int alignment)
  84 {
  85   unsigned char results[16];
  86
  87   md5_signature((unsigned char*)key, key_length, results);
  88   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  89     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
  90     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
  91     | (results[0 + alignment * 4] & 0xFF);
  92 }
  93
  94 static int continuum_item_cmp(const void *t1, const void *t2)
  95 {
  96   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  97   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
  98
  99   /* Why 153? Hmmm... */
 100   WATCHPOINT_ASSERT(ct1->value != 153);
 101   if (ct1->value == ct2->value)
 102     return 0;
 103   else if (ct1->value > ct2->value)
 104     return 1;
 105   else
 106     return -1;
 107 }
 108
 109 static memcached_return_t update_continuum(memcached_st *ptr)
 110 {
 111   uint32_t host_index;
 112   uint32_t continuum_index= 0;
 113   uint32_t value;
 114   memcached_server_st *list;
 115   uint32_t pointer_index;
 116   uint32_t pointer_counter= 0;
 117   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 118   uint32_t pointer_per_hash= 1;
 119   uint64_t total_weight= 0;
 120   uint64_t is_ketama_weighted= 0;
 121   uint64_t is_auto_ejecting= 0;
 122   uint32_t points_per_server= 0;
 123   uint32_t live_servers= 0;
 124   struct timeval now;
 125
 126   if (gettimeofday(&now, NULL) != 0)
 127   {
 128     ptr->cached_errno = errno;
 129     return MEMCACHED_ERRNO;
 130   }
 131
 132   list = ptr->hosts;
 133
 134   /* count live servers (those without a retry delay set) */
 135   is_auto_ejecting= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS);
 136   if (is_auto_ejecting)
 137   {
 138     live_servers= 0;
 139     ptr->next_distribution_rebuild= 0;
 140     for (host_index= 0; host_index < ptr->number_of_hosts; ++host_index)
 141     {
 142       if (list[host_index].next_retry <= now.tv_sec)
 143         live_servers++;
 144       else
 145       {
 146         if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
 147           ptr->next_distribution_rebuild= list[host_index].next_retry;
 148       }
 149     }
 150   }
 151   else
 152     live_servers= ptr->number_of_hosts;
 153
 154   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 155   points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 156
 157   if (live_servers == 0)
 158     return MEMCACHED_SUCCESS;
 159
 160   if (live_servers > ptr->continuum_count)
 161   {
 162     memcached_continuum_item_st *new_ptr;
 163
 164     new_ptr= ptr->call_realloc(ptr, ptr->continuum,
 165                                sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 166
 167     if (new_ptr == 0)
 168       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 169
 170     ptr->continuum= new_ptr;
 171     ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 172   }
 173
 174   if (is_ketama_weighted)
 175   {
 176     for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 177     {
 178       if (list[host_index].weight == 0)
 179       {
 180         list[host_index].weight = 1;
 181       }
 182       if (!is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 183         total_weight += list[host_index].weight;
 184     }
 185   }
 186
 187   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 188   {
 189     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 190       continue;
 191
 192     if (is_ketama_weighted)
 193     {
 194         float pct = (float)list[host_index].weight / (float)total_weight;
 195         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 196         pointer_per_hash= 4;
 197 #ifdef DEBUG
 198         printf("ketama_weighted:%s|%d|%llu|%u\n",
 199                list[host_index].hostname,
 200                list[host_index].port,
 201                (unsigned long long)list[host_index].weight,
 202                pointer_per_server);
 203 #endif
 204     }
 205
 206
 207     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 208     {
 209       for (pointer_index= 0;
 210            pointer_index < pointer_per_server / pointer_per_hash;
 211            pointer_index++)
 212       {
 213         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 214         size_t sort_host_length;
 215
 216         // Spymemcached ketema key format is: hostname/ip:port-index
 217         // If hostname is not available then: /ip:port-index
 218         sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 219                                             "/%s:%u-%u",
 220                                             list[host_index].hostname,
 221                                             (uint32_t)list[host_index].port,
 222                                             pointer_index);
 223 #ifdef DEBUG
 224         printf("update_continuum: key is %s\n", sort_host);
 225 #endif
 226
 227         WATCHPOINT_ASSERT(sort_host_length);
 228
 229         if (is_ketama_weighted)
 230         {
 231           unsigned int i;
 232           for (i = 0; i < pointer_per_hash; i++)
 233           {
 234              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
 235              ptr->continuum[continuum_index].index= host_index;
 236              ptr->continuum[continuum_index++].value= value;
 237           }
 238         }
 239         else
 240         {
 241           value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->distribution_hash);
 242           ptr->continuum[continuum_index].index= host_index;
 243           ptr->continuum[continuum_index++].value= value;
 244         }
 245       }
 246     }
 247     else
 248     {
 249       for (pointer_index= 1;
 250            pointer_index <= pointer_per_server / pointer_per_hash;
 251            pointer_index++)
 252       {
 253         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 254         size_t sort_host_length;
 255
 256         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 257         {
 258           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 259                                               "%s-%u",
 260                                               list[host_index].hostname,
 261                                               pointer_index - 1);
 262         }
 263         else
 264         {
 265           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 266                                               "%s:%u-%u",
 267                                               list[host_index].hostname,
 268                                               (uint32_t)list[host_index].port,
 269                                               pointer_index - 1);
 270         }
 271
 272         WATCHPOINT_ASSERT(sort_host_length);
 273
 274         if (is_ketama_weighted)
 275         {
 276           unsigned int i;
 277           for (i = 0; i < pointer_per_hash; i++)
 278           {
 279              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
 280              ptr->continuum[continuum_index].index= host_index;
 281              ptr->continuum[continuum_index++].value= value;
 282           }
 283         }
 284         else
 285         {
 286           value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->distribution_hash);
 287           ptr->continuum[continuum_index].index= host_index;
 288           ptr->continuum[continuum_index++].value= value;
 289         }
 290       }
 291     }
 292
 293     pointer_counter+= pointer_per_server;
 294   }
 295
 296   WATCHPOINT_ASSERT(ptr);
 297   WATCHPOINT_ASSERT(ptr->continuum);
 298   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 299   ptr->continuum_points_counter= pointer_counter;
 300   qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 301
 302 #ifdef DEBUG
 303   for (pointer_index= 0; ptr->number_of_hosts && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 304   {
 305     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 306   }
 307 #endif
 308
 309   return MEMCACHED_SUCCESS;
 310 }
 311
 312
 313 memcached_return_t memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 314 {
 315   unsigned int x;
 316   uint16_t count;
 317   memcached_server_st *new_host_list;
 318
 319   if (!list)
 320     return MEMCACHED_SUCCESS;
 321
 322   count= list[0].count;
 323   new_host_list= ptr->call_realloc(ptr, ptr->hosts,
 324                                    sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 325
 326   if (!new_host_list)
 327     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 328
 329   ptr->hosts= new_host_list;
 330
 331   for (x= 0; x < count; x++)
 332   {
 333     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 334             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 335             && ! (ptr->flags.use_udp)) )
 336       return MEMCACHED_INVALID_HOST_PROTOCOL;
 337
 338     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 339     memcached_server_create(ptr, &ptr->hosts[ptr->number_of_hosts]);
 340     /* TODO check return type */
 341     (void)memcached_server_create_with(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 342                                        list[x].port, list[x].weight, list[x].type);
 343     ptr->number_of_hosts++;
 344   }
 345   ptr->hosts[0].count= (uint16_t) ptr->number_of_hosts;
 346
 347   return run_distribution(ptr);
 348 }
 349
 350 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 351                                                     const char *filename)
 352 {
 353   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 354 }
 355
 356 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 357                                                                 const char *filename,
 358                                                                 uint32_t weight)
 359 {
 360   if (!filename)
 361     return MEMCACHED_FAILURE;
 362
 363   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 364 }
 365
 366 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 367                                             const char *hostname,
 368                                             in_port_t port)
 369 {
 370   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 371 }
 372
 373 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 374                                                         const char *hostname,
 375                                                         in_port_t port,
 376                                                         uint32_t weight)
 377 {
 378   if (!port)
 379     port= MEMCACHED_DEFAULT_PORT;
 380
 381   if (!hostname)
 382     hostname= "localhost";
 383
 384   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 385 }
 386
 387 memcached_return_t memcached_server_add(memcached_st *ptr,
 388                                         const char *hostname,
 389                                         in_port_t port)
 390 {
 391   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 392 }
 393
 394 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 395                                                     const char *hostname,
 396                                                     in_port_t port,
 397                                                     uint32_t weight)
 398 {
 399   if (!port)
 400     port= MEMCACHED_DEFAULT_PORT;
 401
 402   if (!hostname)
 403     hostname= "localhost";
 404
 405   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 406 }
 407
 408 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 409                                      in_port_t port,
 410                                      uint32_t weight,
 411                                      memcached_connection_t type)
 412 {
 413   memcached_server_st *new_host_list;
 414
 415   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 416       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 417     return MEMCACHED_INVALID_HOST_PROTOCOL;
 418
 419   new_host_list= ptr->call_realloc(ptr, ptr->hosts,
 420                                    sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 421
 422   if (new_host_list == NULL)
 423     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 424
 425   ptr->hosts= new_host_list;
 426
 427   /* TODO: Check return type */
 428   (void)memcached_server_create_with(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, weight, type);
 429   ptr->number_of_hosts++;
 430   ptr->hosts[0].count= (uint16_t) ptr->number_of_hosts;
 431
 432   return run_distribution(ptr);
 433 }
 434
 435 memcached_return_t memcached_server_remove(memcached_server_st *st_ptr)
 436 {
 437   uint32_t x, host_index;
 438   memcached_st *ptr= st_ptr->root;
 439   memcached_server_st *list= ptr->hosts;
 440
 441   for (x= 0, host_index= 0; x < ptr->number_of_hosts; x++)
 442   {
 443     if (strncmp(list[x].hostname, st_ptr->hostname, MEMCACHED_MAX_HOST_LENGTH) != 0 || list[x].port != st_ptr->port)
 444     {
 445       if (host_index != x)
 446         memcpy(list+host_index, list+x, sizeof(memcached_server_st));
 447       host_index++;
 448     }
 449   }
 450   ptr->number_of_hosts= host_index;
 451
 452   if (st_ptr->address_info)
 453   {
 454     freeaddrinfo(st_ptr->address_info);
 455     st_ptr->address_info= NULL;
 456   }
 457   run_distribution(ptr);
 458
 459   return MEMCACHED_SUCCESS;
 460 }
 461
 462 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 463                                                   const char *hostname, in_port_t port,
 464                                                   memcached_return_t *error)
 465 {
 466   return memcached_server_list_append_with_weight(ptr, hostname, port, 0, error);
 467 }
 468
 469 memcached_server_st *memcached_server_list_append_with_weight(memcached_server_st *ptr,
 470                                                               const char *hostname, in_port_t port,
 471                                                               uint32_t weight,
 472                                                               memcached_return_t *error)
 473 {
 474   unsigned int count;
 475   memcached_server_st *new_host_list;
 476
 477   if (hostname == NULL || error == NULL)
 478     return NULL;
 479
 480   if (!port)
 481     port= MEMCACHED_DEFAULT_PORT;
 482
 483   /* Increment count for hosts */
 484   count= 1;
 485   if (ptr != NULL)
 486   {
 487     count+= ptr[0].count;
 488   }
 489
 490   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 491   if (!new_host_list)
 492   {
 493     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 494     return NULL;
 495   }
 496
 497   /* TODO: Check return type */
 498   memcached_server_create_with(NULL, &new_host_list[count-1], hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 499
 500   /* Backwards compatibility hack */
 501   new_host_list[0].count= (uint16_t) count;
 502
 503   *error= MEMCACHED_SUCCESS;
 504   return new_host_list;
 505 }
 506
 507 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 508 {
 509   if (ptr == NULL)
 510     return 0;
 511
 512   return ptr[0].count;
 513 }
 514
 515 void memcached_server_list_free(memcached_server_st *ptr)
 516 {
 517   server_list_free(NULL, ptr);
 518 }