git.m6w6.name Git - m6w6/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     return_value= (int) (a->port - b->port);
  44   }
  45
  46   return return_value;
  47 }
  48
  49 void sort_hosts(memcached_st *ptr)
  50 {
  51   if (ptr->number_of_hosts)
  52   {
  53     qsort(ptr->hosts, ptr->number_of_hosts, sizeof(memcached_server_st), compare_servers);
  54     ptr->hosts[0].count= ptr->number_of_hosts;
  55   }
  56 }
  57
  58 static void host_reset(memcached_st *ptr, memcached_server_st *host,
  59                        char *hostname, unsigned int port,
  60                        memcached_connection type)
  61 {
  62   memset(host,  0, sizeof(memcached_server_st));
  63   strncpy(host->hostname, hostname, MEMCACHED_MAX_HOST_LENGTH - 1);
  64   host->root= ptr ? ptr : NULL;
  65   host->port= port;
  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       freeaddrinfo(servers[x].address_info);
  84
  85   if (ptr && ptr->call_free)
  86     ptr->call_free(ptr, servers);
  87   else
  88     free(servers);
  89 }
  90
  91 static int continuum_item_cmp(const void *t1, const void *t2)
  92 {
  93   struct continuum_item *ct1 = (struct continuum_item *)t1;
  94   struct continuum_item *ct2 = (struct continuum_item *)t2;
  95
  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 static uint32_t internal_generate_ketama_md5(char *key, size_t key_length)
 106 {
 107   unsigned char results[16];
 108
 109   md5_signature((unsigned char*)key, (unsigned int)key_length, results);
 110
 111   return ( (results[3] ) << 24)
 112     | ( (results[2] ) << 16)
 113     | ( (results[1] ) << 8)
 114     | ( results[0] );
 115 }
 116
 117 void update_continuum(memcached_st *ptr)
 118 {
 119   uint32_t index;
 120   uint32_t host_index;
 121   uint32_t continuum_index= 0;
 122   uint32_t value;
 123   memcached_server_st *list = ptr->hosts;
 124
 125   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 126   {
 127     for(index= 1; index <= MEMCACHED_POINTS_PER_SERVER; ++index)
 128     {
 129       char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 130       size_t sort_host_length;
 131
 132       sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH, "%s:%d-%d",
 133                                  list[host_index].hostname, list[host_index].port, index);
 134       WATCHPOINT_ASSERT(sort_host_length);
 135       value= internal_generate_ketama_md5(sort_host, sort_host_length);
 136       ptr->continuum[continuum_index].index= host_index;
 137       ptr->continuum[continuum_index++].value= value;
 138     }
 139   }
 140
 141   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 142   qsort(ptr->continuum, ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER, sizeof(struct continuum_item), continuum_item_cmp);
 143 #ifdef HAVE_DEBUG
 144   for (index= 0; index < ((ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER) - 1); index++)
 145   {
 146     WATCHPOINT_ASSERT(ptr->continuum[index].value <= ptr->continuum[index + 1].value);
 147   }
 148 #endif
 149 }
 150
 151
 152 memcached_return memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 153 {
 154   unsigned int x;
 155   uint16_t count;
 156   memcached_server_st *new_host_list;
 157
 158   if (!list)
 159     return MEMCACHED_SUCCESS;
 160
 161   count= list[0].count;
 162
 163   if (ptr->call_realloc)
 164     new_host_list=
 165       (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 166                                                sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 167   else
 168     new_host_list=
 169       (memcached_server_st *)realloc(ptr->hosts,
 170                                      sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 171
 172   if (!new_host_list)
 173     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 174
 175   ptr->hosts= new_host_list;
 176
 177   for (x= 0; x < count; x++)
 178   {
 179     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 180     host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 181                list[x].port, list[x].type);
 182     ptr->number_of_hosts++;
 183   }
 184   ptr->hosts[0].count= ptr->number_of_hosts;
 185
 186   if (ptr->flags & MEM_USE_SORT_HOSTS)
 187     sort_hosts(ptr);
 188
 189   switch (ptr->distribution)
 190   {
 191   case MEMCACHED_DISTRIBUTION_CONSISTENT:
 192   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
 193     update_continuum(ptr);
 194     break;
 195   case MEMCACHED_DISTRIBUTION_CONSISTENT_WHEEL:
 196     rebalance_wheel(ptr);
 197     break;
 198   case MEMCACHED_DISTRIBUTION_MODULA:
 199     break;
 200   default:
 201     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
 202   }
 203
 204   return MEMCACHED_SUCCESS;
 205 }
 206
 207 memcached_return memcached_server_add_unix_socket(memcached_st *ptr, char *filename)
 208 {
 209   if (!filename)
 210     return MEMCACHED_FAILURE;
 211
 212   return server_add(ptr, filename, 0, MEMCACHED_CONNECTION_UNIX_SOCKET);
 213 }
 214
 215 memcached_return memcached_server_add_udp(memcached_st *ptr,
 216                                           char *hostname,
 217                                           unsigned int port)
 218 {
 219   if (!port)
 220     port= MEMCACHED_DEFAULT_PORT;
 221
 222   if (!hostname)
 223     hostname= "localhost";
 224
 225   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_UDP);
 226 }
 227
 228 memcached_return memcached_server_add(memcached_st *ptr,
 229                                       char *hostname,
 230                                       unsigned int port)
 231 {
 232   if (!port)
 233     port= MEMCACHED_DEFAULT_PORT;
 234
 235   if (!hostname)
 236     hostname= "localhost";
 237
 238   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_TCP);
 239 }
 240
 241 static memcached_return server_add(memcached_st *ptr, char *hostname,
 242                                    unsigned int port,
 243                                    memcached_connection type)
 244 {
 245   memcached_server_st *new_host_list;
 246   LIBMEMCACHED_MEMCACHED_SERVER_ADD_START();
 247
 248
 249   if (ptr->call_realloc)
 250     new_host_list= (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 251                                                             sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 252   else
 253     new_host_list= (memcached_server_st *)realloc(ptr->hosts,
 254                                                   sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 255   if (new_host_list == NULL)
 256     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 257
 258   ptr->hosts= new_host_list;
 259
 260   host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, type);
 261   ptr->number_of_hosts++;
 262
 263   if (ptr->flags & MEM_USE_SORT_HOSTS)
 264     sort_hosts(ptr);
 265
 266   ptr->hosts[0].count= ptr->number_of_hosts;
 267
 268   switch (ptr->distribution)
 269   {
 270   case MEMCACHED_DISTRIBUTION_CONSISTENT:
 271   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
 272     update_continuum(ptr);
 273     break;
 274   case MEMCACHED_DISTRIBUTION_CONSISTENT_WHEEL:
 275     rebalance_wheel(ptr);
 276     break;
 277   case MEMCACHED_DISTRIBUTION_MODULA:
 278     break;
 279   default:
 280     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
 281   }
 282
 283   LIBMEMCACHED_MEMCACHED_SERVER_ADD_END();
 284
 285   return MEMCACHED_SUCCESS;
 286 }
 287
 288 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 289                                                   char *hostname, unsigned int port,
 290                                                   memcached_return *error)
 291 {
 292   unsigned int count;
 293   memcached_server_st *new_host_list;
 294
 295   if (hostname == NULL || error == NULL)
 296     return NULL;
 297
 298   if (!port)
 299     port= MEMCACHED_DEFAULT_PORT;
 300
 301   /* Increment count for hosts */
 302   count= 1;
 303   if (ptr != NULL)
 304   {
 305     count+= ptr[0].count;
 306   }
 307
 308   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 309   if (!new_host_list)
 310   {
 311     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 312     return NULL;
 313   }
 314
 315   host_reset(NULL, &new_host_list[count-1], hostname, port, MEMCACHED_CONNECTION_TCP);
 316
 317   /* Backwards compatibility hack */
 318   new_host_list[0].count= count;
 319
 320   *error= MEMCACHED_SUCCESS;
 321   return new_host_list;
 322 }
 323
 324 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 325 {
 326   if (ptr == NULL)
 327     return 0;
 328
 329   return ptr[0].count;
 330 }
 331
 332 void memcached_server_list_free(memcached_server_st *ptr)
 333 {
 334   server_list_free(NULL, ptr);
 335 }