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