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