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