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

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