git.m6w6.name Git - awesomized/libmemcached/blob - libmemcached/memcached_hosts.c

   1 #include "common.h"
   2
   3 /* Protoypes (static) */
   4 static memcached_return server_add(memcached_st *ptr, char *hostname,
   5                                    unsigned int port,
   6                                    memcached_connection type);
   7
   8 #define MEMCACHED_WHEEL_SIZE 1024
   9 #define MEMCACHED_STRIDE 4
  10 static void rebalance_wheel(memcached_st *ptr)
  11 {
  12   unsigned int x;
  13   unsigned int y;
  14   unsigned int latch;
  15
  16   /* Seed the Wheel */
  17   memset(ptr->wheel, 0, sizeof(unsigned int) * MEMCACHED_WHEEL_SIZE);
  18
  19   for (latch= y= x= 0; x < MEMCACHED_WHEEL_SIZE; x++, latch++)
  20   {
  21     if (latch == MEMCACHED_STRIDE)
  22     {
  23       y++;
  24       if (y == ptr->number_of_hosts)
  25         y= 0;
  26       latch= 0;
  27     }
  28
  29     ptr->wheel[x]= y;
  30   }
  31 }
  32
  33 static int compare_servers(const void *p1, const void *p2)
  34 {
  35   int return_value;
  36   memcached_server_st *a= (memcached_server_st *)p1;
  37   memcached_server_st *b= (memcached_server_st *)p2;
  38
  39   return_value= strcmp(a->hostname, b->hostname);
  40
  41   if (return_value == 0)
  42   {
  43     if (a->port > b->port)
  44       return_value++;
  45     else
  46       return_value--;
  47   }
  48
  49   return return_value;
  50 }
  51
  52 void sort_hosts(memcached_st *ptr)
  53 {
  54   if (ptr->number_of_hosts)
  55   {
  56     qsort(ptr->hosts, ptr->number_of_hosts, sizeof(memcached_server_st), compare_servers);
  57     ptr->hosts[0].count= ptr->number_of_hosts;
  58   }
  59 }
  60
  61 static void host_reset(memcached_st *ptr, memcached_server_st *host,
  62                        char *hostname, unsigned int port,
  63                        memcached_connection type)
  64 {
  65   memset(host,  0, sizeof(memcached_server_st));
  66   strncpy(host->hostname, hostname, MEMCACHED_MAX_HOST_LENGTH - 1);
  67   host->root= ptr ? ptr : NULL;
  68   host->port= port;
  69   host->fd= -1;
  70   host->type= type;
  71   host->read_ptr= host->read_buffer;
  72   if (ptr)
  73     host->next_retry= ptr->retry_timeout;
  74   host->sockaddr_inited= MEMCACHED_NOT_ALLOCATED;
  75 }
  76
  77 void server_list_free(memcached_st *ptr, memcached_server_st *servers)
  78 {
  79   unsigned int x;
  80
  81   if (servers == NULL)
  82     return;
  83
  84   for (x= 0; x < servers->count; x++)
  85     if (servers[x].address_info)
  86       freeaddrinfo(servers[x].address_info);
  87
  88   if (ptr && ptr->call_free)
  89     ptr->call_free(ptr, servers);
  90   else
  91     free(servers);
  92 }
  93
  94 static int continuum_item_cmp(const void *t1, const void *t2)
  95 {
  96   struct continuum_item *ct1 = (struct continuum_item *)t1;
  97   struct continuum_item *ct2 = (struct continuum_item *)t2;
  98
  99   WATCHPOINT_ASSERT(ct1->value != 153);
 100   if (ct1->value == ct2->value)
 101     return 0;
 102   else if (ct1->value > ct2->value)
 103     return 1;
 104   else
 105     return -1;
 106 }
 107
 108 static uint32_t internal_generate_ketama_md5(char *key, size_t key_length)
 109 {
 110   unsigned char results[16];
 111
 112   md5_signature((unsigned char*)key, (unsigned int)key_length, results);
 113
 114   return ( (results[3] ) << 24)
 115     | ( (results[2] ) << 16)
 116     | ( (results[1] ) << 8)
 117     | ( results[0] );
 118 }
 119
 120 void 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 = ptr->hosts;
 127
 128   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 129   {
 130     for(index= 1; index <= MEMCACHED_POINTS_PER_SERVER; ++index)
 131     {
 132       char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 133       size_t sort_host_length;
 134
 135       sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH, "%s:%d-%d",
 136                                  list[host_index].hostname, list[host_index].port, index);
 137       WATCHPOINT_ASSERT(sort_host_length);
 138       value= internal_generate_ketama_md5(sort_host, sort_host_length);
 139       ptr->continuum[continuum_index].index= host_index;
 140       ptr->continuum[continuum_index++].value= value;
 141     }
 142   }
 143
 144   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 145   qsort(ptr->continuum, ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER, sizeof(struct continuum_item), continuum_item_cmp);
 146 #ifdef HAVE_DEBUG
 147   for (index= 0; index < ((ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER) - 1); index++)
 148   {
 149     WATCHPOINT_ASSERT(ptr->continuum[index].value <= ptr->continuum[index + 1].value);
 150   }
 151 #endif
 152 }
 153
 154
 155 memcached_return memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 156 {
 157   unsigned int x;
 158   uint16_t count;
 159   memcached_server_st *new_host_list;
 160
 161   if (!list)
 162     return MEMCACHED_SUCCESS;
 163
 164   count= list[0].count;
 165
 166   if (ptr->call_realloc)
 167     new_host_list=
 168       (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 169                                                sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 170   else
 171     new_host_list=
 172       (memcached_server_st *)realloc(ptr->hosts,
 173                                      sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 174
 175   if (!new_host_list)
 176     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 177
 178   ptr->hosts= new_host_list;
 179
 180   for (x= 0; x < count; x++)
 181   {
 182     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 183     host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 184                list[x].port, list[x].type);
 185     ptr->number_of_hosts++;
 186   }
 187   ptr->hosts[0].count= ptr->number_of_hosts;
 188
 189   if (ptr->flags & MEM_USE_SORT_HOSTS)
 190     sort_hosts(ptr);
 191
 192   switch (ptr->distribution)
 193   {
 194   case MEMCACHED_DISTRIBUTION_CONSISTENT:
 195   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
 196     update_continuum(ptr);
 197     break;
 198   case MEMCACHED_DISTRIBUTION_CONSISTENT_WHEEL:
 199     rebalance_wheel(ptr);
 200     break;
 201   case MEMCACHED_DISTRIBUTION_MODULA:
 202     break;
 203   default:
 204     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
 205   }
 206
 207   return MEMCACHED_SUCCESS;
 208 }
 209
 210 memcached_return memcached_server_add_unix_socket(memcached_st *ptr, char *filename)
 211 {
 212   if (!filename)
 213     return MEMCACHED_FAILURE;
 214
 215   return server_add(ptr, filename, 0, MEMCACHED_CONNECTION_UNIX_SOCKET);
 216 }
 217
 218 memcached_return memcached_server_add_udp(memcached_st *ptr,
 219                                           char *hostname,
 220                                           unsigned int port)
 221 {
 222   if (!port)
 223     port= MEMCACHED_DEFAULT_PORT;
 224
 225   if (!hostname)
 226     hostname= "localhost";
 227
 228   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_UDP);
 229 }
 230
 231 memcached_return memcached_server_add(memcached_st *ptr,
 232                                       char *hostname,
 233                                       unsigned int port)
 234 {
 235   if (!port)
 236     port= MEMCACHED_DEFAULT_PORT;
 237
 238   if (!hostname)
 239     hostname= "localhost";
 240
 241   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_TCP);
 242 }
 243
 244 static memcached_return server_add(memcached_st *ptr, char *hostname,
 245                                    unsigned int port,
 246                                    memcached_connection type)
 247 {
 248   memcached_server_st *new_host_list;
 249   LIBMEMCACHED_MEMCACHED_SERVER_ADD_START();
 250
 251
 252   if (ptr->call_realloc)
 253     new_host_list= (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 254                                                             sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 255   else
 256     new_host_list= (memcached_server_st *)realloc(ptr->hosts,
 257                                                   sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 258   if (new_host_list == NULL)
 259     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 260
 261   ptr->hosts= new_host_list;
 262
 263   host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, type);
 264   ptr->number_of_hosts++;
 265
 266   if (ptr->flags & MEM_USE_SORT_HOSTS)
 267     sort_hosts(ptr);
 268
 269   ptr->hosts[0].count= ptr->number_of_hosts;
 270
 271   switch (ptr->distribution)
 272   {
 273   case MEMCACHED_DISTRIBUTION_CONSISTENT:
 274   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
 275     update_continuum(ptr);
 276     break;
 277   case MEMCACHED_DISTRIBUTION_CONSISTENT_WHEEL:
 278     rebalance_wheel(ptr);
 279     break;
 280   case MEMCACHED_DISTRIBUTION_MODULA:
 281     break;
 282   default:
 283     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
 284   }
 285
 286   LIBMEMCACHED_MEMCACHED_SERVER_ADD_END();
 287
 288   return MEMCACHED_SUCCESS;
 289 }
 290
 291 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 292                                                   char *hostname, unsigned int port,
 293                                                   memcached_return *error)
 294 {
 295   unsigned int count;
 296   memcached_server_st *new_host_list;
 297
 298   if (hostname == NULL || error == NULL)
 299     return NULL;
 300
 301   if (!port)
 302     port= MEMCACHED_DEFAULT_PORT;
 303
 304   /* Increment count for hosts */
 305   count= 1;
 306   if (ptr != NULL)
 307   {
 308     count+= ptr[0].count;
 309   }
 310
 311   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 312   if (!new_host_list)
 313   {
 314     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 315     return NULL;
 316   }
 317
 318   host_reset(NULL, &new_host_list[count-1], hostname, port, MEMCACHED_CONNECTION_TCP);
 319
 320   /* Backwards compatibility hack */
 321   new_host_list[0].count= count;
 322
 323   *error= MEMCACHED_SUCCESS;
 324   return new_host_list;
 325 }
 326
 327 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 328 {
 329   if (ptr == NULL)
 330     return 0;
 331
 332   return ptr[0].count;
 333 }
 334
 335 void memcached_server_list_free(memcached_server_st *ptr)
 336 {
 337   server_list_free(NULL, ptr);
 338 }