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= (uint16_t) 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   ptr->last_disconnected_server = NULL;
  55
  56   return MEMCACHED_SUCCESS;
  57 }
  58
  59 void server_list_free(memcached_st *ptr, memcached_server_st *servers)
  60 {
  61   unsigned int x;
  62
  63   if (servers == NULL)
  64     return;
  65
  66   for (x= 0; x < servers->count; x++)
  67     if (servers[x].address_info)
  68     {
  69       freeaddrinfo(servers[x].address_info);
  70       servers[x].address_info= NULL;
  71     }
  72
  73   if (ptr)
  74     ptr->call_free(ptr, servers);
  75   else
  76     free(servers);
  77 }
  78
  79 static uint32_t ketama_server_hash(const char *key, unsigned int key_length, int alignment)
  80 {
  81   unsigned char results[16];
  82
  83   md5_signature((unsigned char*)key, key_length, results);
  84   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  85     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
  86     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
  87     | (results[0 + alignment * 4] & 0xFF);
  88 }
  89
  90 static int continuum_item_cmp(const void *t1, const void *t2)
  91 {
  92   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  93   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
  94
  95   /* Why 153? Hmmm... */
  96   WATCHPOINT_ASSERT(ct1->value != 153);
  97   if (ct1->value == ct2->value)
  98     return 0;
  99   else if (ct1->value > ct2->value)
 100     return 1;
 101   else
 102     return -1;
 103 }
 104
 105 memcached_return update_continuum(memcached_st *ptr)
 106 {
 107   uint32_t host_index;
 108   uint32_t continuum_index= 0;
 109   uint32_t value;
 110   memcached_server_st *list;
 111   uint32_t pointer_index;
 112   uint32_t pointer_counter= 0;
 113   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 114   uint32_t pointer_per_hash= 1;
 115   uint64_t total_weight= 0;
 116   uint64_t is_ketama_weighted= 0;
 117   uint64_t is_auto_ejecting= 0;
 118   uint32_t points_per_server= 0;
 119   uint32_t live_servers= 0;
 120   struct timeval now;
 121
 122   if (gettimeofday(&now, NULL) != 0)
 123   {
 124     ptr->cached_errno = errno;
 125     return MEMCACHED_ERRNO;
 126   }
 127
 128   list = ptr->hosts;
 129
 130   /* count live servers (those without a retry delay set) */
 131   is_auto_ejecting= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS);
 132   if (is_auto_ejecting)
 133   {
 134     live_servers= 0;
 135     ptr->next_distribution_rebuild= 0;
 136     for (host_index= 0; host_index < ptr->number_of_hosts; ++host_index)
 137     {
 138       if (list[host_index].next_retry <= now.tv_sec)
 139         live_servers++;
 140       else
 141       {
 142         if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
 143           ptr->next_distribution_rebuild= list[host_index].next_retry;
 144       }
 145     }
 146   }
 147   else
 148     live_servers= ptr->number_of_hosts;
 149
 150   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 151   points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 152
 153   if (live_servers == 0)
 154     return MEMCACHED_SUCCESS;
 155
 156   if (live_servers > ptr->continuum_count)
 157   {
 158     memcached_continuum_item_st *new_ptr;
 159
 160     new_ptr= ptr->call_realloc(ptr, ptr->continuum,
 161                                sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 162
 163     if (new_ptr == 0)
 164       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 165
 166     ptr->continuum= new_ptr;
 167     ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 168   }
 169
 170   if (is_ketama_weighted)
 171   {
 172     for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 173     {
 174       if (list[host_index].weight == 0)
 175       {
 176         list[host_index].weight = 1;
 177       }
 178       if (!is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 179         total_weight += list[host_index].weight;
 180     }
 181   }
 182
 183   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 184   {
 185     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 186       continue;
 187
 188     if (is_ketama_weighted)
 189     {
 190         float pct = (float)list[host_index].weight / (float)total_weight;
 191         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 192         pointer_per_hash= 4;
 193 #ifdef DEBUG
 194         printf("ketama_weighted:%s|%d|%llu|%u\n",
 195                list[host_index].hostname,
 196                list[host_index].port,
 197                (unsigned long long)list[host_index].weight,
 198                pointer_per_server);
 199 #endif
 200     }
 201     for (pointer_index= 1;
 202          pointer_index <= pointer_per_server / pointer_per_hash;
 203          ++pointer_index)
 204     {
 205       char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 206       size_t sort_host_length;
 207
 208       if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 209       {
 210         sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 211                                             "%s-%d",
 212                                             list[host_index].hostname,
 213                                             pointer_index - 1);
 214
 215       }
 216       else
 217       {
 218         sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 219                                             "%s:%d-%d",
 220                                             list[host_index].hostname,
 221                                             list[host_index].port, pointer_index - 1);
 222       }
 223       WATCHPOINT_ASSERT(sort_host_length);
 224
 225       if (is_ketama_weighted)
 226       {
 227         unsigned int i;
 228         for (i = 0; i < pointer_per_hash; i++)
 229         {
 230           value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
 231           ptr->continuum[continuum_index].index= host_index;
 232           ptr->continuum[continuum_index++].value= value;
 233         }
 234       }
 235       else
 236       {
 237         value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->hash_continuum);
 238         ptr->continuum[continuum_index].index= host_index;
 239         ptr->continuum[continuum_index++].value= value;
 240       }
 241     }
 242     pointer_counter+= pointer_per_server;
 243   }
 244
 245   WATCHPOINT_ASSERT(ptr);
 246   WATCHPOINT_ASSERT(ptr->continuum);
 247   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 248   ptr->continuum_points_counter= pointer_counter;
 249   qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 250
 251 #ifdef DEBUG
 252   for (pointer_index= 0; ptr->number_of_hosts && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 253   {
 254     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 255   }
 256 #endif
 257
 258   return MEMCACHED_SUCCESS;
 259 }
 260
 261
 262 memcached_return memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 263 {
 264   unsigned int x;
 265   uint16_t count;
 266   memcached_server_st *new_host_list;
 267
 268   if (!list)
 269     return MEMCACHED_SUCCESS;
 270
 271   count= list[0].count;
 272   new_host_list= ptr->call_realloc(ptr, ptr->hosts,
 273                                    sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 274
 275   if (!new_host_list)
 276     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 277
 278   ptr->hosts= new_host_list;
 279
 280   for (x= 0; x < count; x++)
 281   {
 282     if ((ptr->flags & MEM_USE_UDP && list[x].type != MEMCACHED_CONNECTION_UDP)
 283             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 284             && ! (ptr->flags & MEM_USE_UDP)) )
 285       return MEMCACHED_INVALID_HOST_PROTOCOL;
 286
 287     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 288     memcached_server_create(ptr, &ptr->hosts[ptr->number_of_hosts]);
 289     /* TODO check return type */
 290     (void)memcached_server_create_with(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 291                                        list[x].port, list[x].weight, list[x].type);
 292     ptr->number_of_hosts++;
 293   }
 294   ptr->hosts[0].count= (uint16_t) ptr->number_of_hosts;
 295
 296   return run_distribution(ptr);
 297 }
 298
 299 memcached_return memcached_server_add_unix_socket(memcached_st *ptr,
 300                                                   const char *filename)
 301 {
 302   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 303 }
 304
 305 memcached_return memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 306                                                               const char *filename,
 307                                                               uint32_t weight)
 308 {
 309   if (!filename)
 310     return MEMCACHED_FAILURE;
 311
 312   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 313 }
 314
 315 memcached_return memcached_server_add_udp(memcached_st *ptr,
 316                                           const char *hostname,
 317                                           unsigned int port)
 318 {
 319   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 320 }
 321
 322 memcached_return memcached_server_add_udp_with_weight(memcached_st *ptr,
 323                                                       const char *hostname,
 324                                                       unsigned int port,
 325                                                       uint32_t weight)
 326 {
 327   if (!port)
 328     port= MEMCACHED_DEFAULT_PORT;
 329
 330   if (!hostname)
 331     hostname= "localhost";
 332
 333   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 334 }
 335
 336 memcached_return memcached_server_add(memcached_st *ptr,
 337                                       const char *hostname,
 338                                       unsigned int port)
 339 {
 340   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 341 }
 342
 343 memcached_return memcached_server_add_with_weight(memcached_st *ptr,
 344                                                   const char *hostname,
 345                                                   unsigned int port,
 346                                                   uint32_t weight)
 347 {
 348   if (!port)
 349     port= MEMCACHED_DEFAULT_PORT;
 350
 351   if (!hostname)
 352     hostname= "localhost";
 353
 354   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 355 }
 356
 357 static memcached_return server_add(memcached_st *ptr, const char *hostname,
 358                                    unsigned int port,
 359                                    uint32_t weight,
 360                                    memcached_connection type)
 361 {
 362   memcached_server_st *new_host_list;
 363
 364   if ( (ptr->flags & MEM_USE_UDP && type != MEMCACHED_CONNECTION_UDP)
 365       || ( (type == MEMCACHED_CONNECTION_UDP) && !(ptr->flags & MEM_USE_UDP) ) )
 366     return MEMCACHED_INVALID_HOST_PROTOCOL;
 367
 368   new_host_list= ptr->call_realloc(ptr, ptr->hosts,
 369                                    sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 370
 371   if (new_host_list == NULL)
 372     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 373
 374   ptr->hosts= new_host_list;
 375
 376   /* TODO: Check return type */
 377   (void)memcached_server_create_with(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, weight, type);
 378   ptr->number_of_hosts++;
 379   ptr->hosts[0].count= (uint16_t) ptr->number_of_hosts;
 380
 381   return run_distribution(ptr);
 382 }
 383
 384 memcached_return memcached_server_remove(memcached_server_st *st_ptr)
 385 {
 386   uint32_t x, host_index;
 387   memcached_st *ptr= st_ptr->root;
 388   memcached_server_st *list= ptr->hosts;
 389
 390   for (x= 0, host_index= 0; x < ptr->number_of_hosts; x++)
 391   {
 392     if (strncmp(list[x].hostname, st_ptr->hostname, MEMCACHED_MAX_HOST_LENGTH) != 0 || list[x].port != st_ptr->port)
 393     {
 394       if (host_index != x)
 395         memcpy(list+host_index, list+x, sizeof(memcached_server_st));
 396       host_index++;
 397     }
 398   }
 399   ptr->number_of_hosts= host_index;
 400
 401   if (st_ptr->address_info)
 402   {
 403     freeaddrinfo(st_ptr->address_info);
 404     st_ptr->address_info= NULL;
 405   }
 406   run_distribution(ptr);
 407
 408   return MEMCACHED_SUCCESS;
 409 }
 410
 411 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 412                                                   const char *hostname, unsigned int port,
 413                                                   memcached_return *error)
 414 {
 415   return memcached_server_list_append_with_weight(ptr, hostname, port, 0, error);
 416 }
 417
 418 memcached_server_st *memcached_server_list_append_with_weight(memcached_server_st *ptr,
 419                                                               const char *hostname, unsigned int port,
 420                                                               uint32_t weight,
 421                                                               memcached_return *error)
 422 {
 423   unsigned int count;
 424   memcached_server_st *new_host_list;
 425
 426   if (hostname == NULL || error == NULL)
 427     return NULL;
 428
 429   if (!port)
 430     port= MEMCACHED_DEFAULT_PORT;
 431
 432   /* Increment count for hosts */
 433   count= 1;
 434   if (ptr != NULL)
 435   {
 436     count+= ptr[0].count;
 437   }
 438
 439   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 440   if (!new_host_list)
 441   {
 442     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 443     return NULL;
 444   }
 445
 446   /* TODO: Check return type */
 447   memcached_server_create_with(NULL, &new_host_list[count-1], hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 448
 449   /* Backwards compatibility hack */
 450   new_host_list[0].count= (uint16_t) count;
 451
 452   *error= MEMCACHED_SUCCESS;
 453   return new_host_list;
 454 }
 455
 456 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 457 {
 458   if (ptr == NULL)
 459     return 0;
 460
 461   return ptr[0].count;
 462 }
 463
 464 void memcached_server_list_free(memcached_server_st *ptr)
 465 {
 466   server_list_free(NULL, ptr);
 467 }