git.m6w6.name Git - awesomized/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 host_reset(memcached_st *ptr, memcached_server_st *host,
  58                 const char *hostname, unsigned int port, uint32_t weight,
  59                 memcached_connection type)
  60 {
  61   strncpy(host->hostname, hostname, MEMCACHED_MAX_HOST_LENGTH - 1);
  62   host->root= ptr ? ptr : NULL;
  63   host->port= port;
  64   host->weight= weight;
  65   host->fd= -1;
  66   host->type= type;
  67   host->read_ptr= host->read_buffer;
  68   if (ptr)
  69     host->next_retry= ptr->retry_timeout;
  70   host->sockaddr_inited= MEMCACHED_NOT_ALLOCATED;
  71 }
  72
  73 void server_list_free(memcached_st *ptr, memcached_server_st *servers)
  74 {
  75   unsigned int x;
  76
  77   if (servers == NULL)
  78     return;
  79
  80   for (x= 0; x < servers->count; x++)
  81     if (servers[x].address_info)
  82     {
  83       freeaddrinfo(servers[x].address_info);
  84       servers[x].address_info= NULL;
  85     }
  86
  87   if (ptr && ptr->call_free)
  88     ptr->call_free(ptr, servers);
  89   else
  90     free(servers);
  91 }
  92
  93 static uint32_t ketama_server_hash(const char *key, unsigned int key_length, int alignment)
  94 {
  95   unsigned char results[16];
  96
  97   md5_signature((unsigned char*)key, key_length, results);
  98   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  99     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
 100     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
 101     | (results[0 + alignment * 4] & 0xFF);
 102 }
 103
 104 static int continuum_item_cmp(const void *t1, const void *t2)
 105 {
 106   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
 107   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
 108
 109   /* Why 153? Hmmm... */
 110   WATCHPOINT_ASSERT(ct1->value != 153);
 111   if (ct1->value == ct2->value)
 112     return 0;
 113   else if (ct1->value > ct2->value)
 114     return 1;
 115   else
 116     return -1;
 117 }
 118
 119 memcached_return update_continuum(memcached_st *ptr)
 120 {
 121   uint32_t index;
 122   uint32_t host_index;
 123   uint32_t continuum_index= 0;
 124   uint32_t value;
 125   memcached_server_st *list;
 126   uint32_t pointer_counter= 0;
 127   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 128   uint32_t pointer_per_hash= 1;
 129   uint64_t total_weight= 0;
 130   uint32_t is_ketama_weighted= 0;
 131   uint32_t points_per_server= 0;
 132
 133   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 134   points_per_server= is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER;
 135
 136   if (ptr->number_of_hosts > ptr->continuum_count)
 137   {
 138     memcached_continuum_item_st *new_ptr;
 139
 140     if (ptr->call_realloc)
 141       new_ptr= (memcached_continuum_item_st *)ptr->call_realloc(ptr, ptr->continuum, sizeof(memcached_continuum_item_st) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 142     else
 143       new_ptr= (memcached_continuum_item_st *)realloc(ptr->continuum, sizeof(memcached_continuum_item_st) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 144
 145     if (new_ptr == 0)
 146       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 147
 148     ptr->continuum= new_ptr;
 149     ptr->continuum_count= ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION;
 150   }
 151
 152   list = ptr->hosts;
 153
 154   if (is_ketama_weighted)
 155   {
 156     for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 157     {
 158       if (list[host_index].weight == 0)
 159       {
 160         list[host_index].weight = 1;
 161       }
 162       total_weight += list[host_index].weight;
 163     }
 164   }
 165
 166   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 167   {
 168     if (is_ketama_weighted)
 169     {
 170         float pct = (float)list[host_index].weight / (float)total_weight;
 171         pointer_per_server= floorf(pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)(ptr->number_of_hosts) + 0.0000000001) * 4;
 172         pointer_per_hash= 4;
 173 #ifdef HAVE_DEBUG
 174         printf("ketama_weighted:%s|%d|%llu|%u\n",
 175                list[host_index].hostname,
 176                list[host_index].port,
 177                (unsigned long long)list[host_index].weight,
 178                pointer_per_server);
 179 #endif
 180     }
 181     for (index= 1; index <= pointer_per_server / pointer_per_hash; ++index)
 182     {
 183       char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 184       size_t sort_host_length;
 185
 186       if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 187       {
 188         sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH, "%s-%d",
 189                                    list[host_index].hostname, index - 1);
 190
 191       }
 192       else
 193       {
 194         sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH, "%s:%d-%d",
 195                                    list[host_index].hostname, list[host_index].port, index - 1);
 196       }
 197       WATCHPOINT_ASSERT(sort_host_length);
 198
 199       if (is_ketama_weighted)
 200       {
 201         int i;
 202         for (i = 0; i < pointer_per_hash; i++)
 203         {
 204           value= ketama_server_hash(sort_host, sort_host_length, i);
 205           ptr->continuum[continuum_index].index= host_index;
 206           ptr->continuum[continuum_index++].value= value;
 207         }
 208       }
 209       else
 210       {
 211         value= generate_hash_value(sort_host, sort_host_length, ptr->hash_continuum);
 212         ptr->continuum[continuum_index].index= host_index;
 213         ptr->continuum[continuum_index++].value= value;
 214       }
 215     }
 216     pointer_counter+= pointer_per_server;
 217   }
 218
 219   WATCHPOINT_ASSERT(ptr);
 220   WATCHPOINT_ASSERT(ptr->continuum);
 221   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 222   ptr->continuum_points_counter= pointer_counter;
 223   qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 224
 225 #ifdef HAVE_DEBUG
 226   for (index= 0; ptr->number_of_hosts && index < ((ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER) - 1); index++)
 227   {
 228     WATCHPOINT_ASSERT(ptr->continuum[index].value <= ptr->continuum[index + 1].value);
 229   }
 230 #endif
 231
 232   return MEMCACHED_SUCCESS;
 233 }
 234
 235
 236 memcached_return memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 237 {
 238   unsigned int x;
 239   uint16_t count;
 240   memcached_server_st *new_host_list;
 241
 242   if (!list)
 243     return MEMCACHED_SUCCESS;
 244
 245   count= list[0].count;
 246   if (ptr->call_realloc)
 247     new_host_list=
 248       (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 249                                                sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 250   else
 251     new_host_list=
 252       (memcached_server_st *)realloc(ptr->hosts,
 253                                      sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 254
 255   if (!new_host_list)
 256     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 257
 258   ptr->hosts= new_host_list;
 259
 260   for (x= 0; x < count; x++)
 261   {
 262     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 263     host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 264                list[x].port, list[x].weight, list[x].type);
 265     ptr->number_of_hosts++;
 266   }
 267   ptr->hosts[0].count= ptr->number_of_hosts;
 268
 269   return run_distribution(ptr);
 270 }
 271
 272 memcached_return memcached_server_add_unix_socket(memcached_st *ptr,
 273                                                   const char *filename)
 274 {
 275   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 276 }
 277
 278 memcached_return memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 279                                                               const char *filename,
 280                                                               uint32_t weight)
 281 {
 282   if (!filename)
 283     return MEMCACHED_FAILURE;
 284
 285   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 286 }
 287
 288 memcached_return memcached_server_add_udp(memcached_st *ptr,
 289                                           const char *hostname,
 290                                           unsigned int port)
 291 {
 292   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 293 }
 294
 295 memcached_return memcached_server_add_udp_with_weight(memcached_st *ptr,
 296                                                       const char *hostname,
 297                                                       unsigned int port,
 298                                                       uint32_t weight)
 299 {
 300   if (!port)
 301     port= MEMCACHED_DEFAULT_PORT;
 302
 303   if (!hostname)
 304     hostname= "localhost";
 305
 306   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 307 }
 308
 309 memcached_return memcached_server_add(memcached_st *ptr,
 310                                       const char *hostname,
 311                                       unsigned int port)
 312 {
 313   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 314 }
 315
 316 memcached_return memcached_server_add_with_weight(memcached_st *ptr,
 317                                                   const char *hostname,
 318                                                   unsigned int port,
 319                                                   uint32_t weight)
 320 {
 321   if (!port)
 322     port= MEMCACHED_DEFAULT_PORT;
 323
 324   if (!hostname)
 325     hostname= "localhost";
 326
 327   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 328 }
 329
 330 static memcached_return server_add(memcached_st *ptr, const char *hostname,
 331                                    unsigned int port,
 332                                    uint32_t weight,
 333                                    memcached_connection type)
 334 {
 335   memcached_server_st *new_host_list;
 336
 337   if (ptr->call_realloc)
 338     new_host_list= (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 339                                                             sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 340   else
 341     new_host_list= (memcached_server_st *)realloc(ptr->hosts,
 342                                                   sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 343   if (new_host_list == NULL)
 344     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 345
 346   ptr->hosts= new_host_list;
 347
 348   host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, weight, type);
 349   ptr->number_of_hosts++;
 350   ptr->hosts[0].count= ptr->number_of_hosts;
 351
 352   return run_distribution(ptr);
 353 }
 354
 355 memcached_return memcached_server_remove(memcached_server_st *st_ptr)
 356 {
 357   uint32_t x, index;
 358   memcached_st *ptr= st_ptr->root;
 359   memcached_server_st *list= ptr->hosts;
 360
 361   for (x= 0, index= 0; x < ptr->number_of_hosts; x++)
 362   {
 363     if (strncmp(list[x].hostname, st_ptr->hostname, MEMCACHED_MAX_HOST_LENGTH) != 0 || list[x].port != st_ptr->port)
 364     {
 365       if (index != x)
 366         memcpy(list+index, list+x, sizeof(memcached_server_st));
 367       index++;
 368     }
 369   }
 370   ptr->number_of_hosts= index;
 371
 372   if (st_ptr->address_info)
 373   {
 374     freeaddrinfo(st_ptr->address_info);
 375     st_ptr->address_info= NULL;
 376   }
 377   run_distribution(ptr);
 378
 379   return MEMCACHED_SUCCESS;
 380 }
 381
 382 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 383                                                   const char *hostname, unsigned int port,
 384                                                   memcached_return *error)
 385 {
 386   return memcached_server_list_append_with_weight(ptr, hostname, port, 0, error);
 387 }
 388
 389 memcached_server_st *memcached_server_list_append_with_weight(memcached_server_st *ptr,
 390                                                               const char *hostname, unsigned int port,
 391                                                               uint32_t weight,
 392                                                               memcached_return *error)
 393 {
 394   unsigned int count;
 395   memcached_server_st *new_host_list;
 396
 397   if (hostname == NULL || error == NULL)
 398     return NULL;
 399
 400   if (!port)
 401     port= MEMCACHED_DEFAULT_PORT;
 402
 403   /* Increment count for hosts */
 404   count= 1;
 405   if (ptr != NULL)
 406   {
 407     count+= ptr[0].count;
 408   }
 409
 410   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 411   if (!new_host_list)
 412   {
 413     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 414     return NULL;
 415   }
 416
 417   host_reset(NULL, &new_host_list[count-1], hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 418
 419   /* Backwards compatibility hack */
 420   new_host_list[0].count= count;
 421
 422   *error= MEMCACHED_SUCCESS;
 423   return new_host_list;
 424 }
 425
 426 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 427 {
 428   if (ptr == NULL)
 429     return 0;
 430
 431   return ptr[0].count;
 432 }
 433
 434 void memcached_server_list_free(memcached_server_st *ptr)
 435 {
 436   server_list_free(NULL, ptr);
 437 }