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