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 memcached_return update_continuum(memcached_st *ptr);
   8
   9 #define MEMCACHED_WHEEL_SIZE 1024
  10 #define MEMCACHED_STRIDE 4
  11 static void rebalance_wheel(memcached_st *ptr)
  12 {
  13   unsigned int x;
  14   unsigned int y;
  15   unsigned int latch;
  16
  17   /* Seed the Wheel */
  18   memset(ptr->wheel, 0, sizeof(unsigned int) * MEMCACHED_WHEEL_SIZE);
  19
  20   for (latch= y= x= 0; x < MEMCACHED_WHEEL_SIZE; x++, latch++)
  21   {
  22     if (latch == MEMCACHED_STRIDE)
  23     {
  24       y++;
  25       if (y == ptr->number_of_hosts)
  26         y= 0;
  27       latch= 0;
  28     }
  29
  30     ptr->wheel[x]= y;
  31   }
  32 }
  33
  34 static int compare_servers(const void *p1, const void *p2)
  35 {
  36   int return_value;
  37   memcached_server_st *a= (memcached_server_st *)p1;
  38   memcached_server_st *b= (memcached_server_st *)p2;
  39
  40   return_value= strcmp(a->hostname, b->hostname);
  41
  42   if (return_value == 0)
  43   {
  44     return_value= (int) (a->port - b->port);
  45   }
  46
  47   return return_value;
  48 }
  49
  50 void sort_hosts(memcached_st *ptr)
  51 {
  52   if (ptr->number_of_hosts)
  53   {
  54     qsort(ptr->hosts, ptr->number_of_hosts, sizeof(memcached_server_st), compare_servers);
  55     ptr->hosts[0].count= ptr->number_of_hosts;
  56   }
  57 }
  58
  59
  60 memcached_return run_distribution(memcached_st *ptr)
  61 {
  62   switch (ptr->distribution)
  63   {
  64   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  65   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  66     return update_continuum(ptr);
  67   case MEMCACHED_DISTRIBUTION_CONSISTENT_WHEEL:
  68     rebalance_wheel(ptr);
  69     break;
  70   case MEMCACHED_DISTRIBUTION_MODULA:
  71     if (ptr->flags & MEM_USE_SORT_HOSTS)
  72       sort_hosts(ptr);
  73     break;
  74   default:
  75     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  76   }
  77
  78   return MEMCACHED_SUCCESS;
  79 }
  80
  81 static void host_reset(memcached_st *ptr, memcached_server_st *host,
  82                        char *hostname, unsigned int port,
  83                        memcached_connection type)
  84 {
  85   memset(host,  0, sizeof(memcached_server_st));
  86   strncpy(host->hostname, hostname, MEMCACHED_MAX_HOST_LENGTH - 1);
  87   host->root= ptr ? ptr : NULL;
  88   host->port= port;
  89   host->fd= -1;
  90   host->type= type;
  91   host->read_ptr= host->read_buffer;
  92   if (ptr)
  93     host->next_retry= ptr->retry_timeout;
  94   host->sockaddr_inited= MEMCACHED_NOT_ALLOCATED;
  95 }
  96
  97 void server_list_free(memcached_st *ptr, memcached_server_st *servers)
  98 {
  99   unsigned int x;
 100
 101   if (servers == NULL)
 102     return;
 103
 104   for (x= 0; x < servers->count; x++)
 105     if (servers[x].address_info)
 106       freeaddrinfo(servers[x].address_info);
 107
 108   if (ptr && ptr->call_free)
 109     ptr->call_free(ptr, servers);
 110   else
 111     free(servers);
 112 }
 113
 114 static int continuum_item_cmp(const void *t1, const void *t2)
 115 {
 116   memcached_continuum_item_st *ct1 = (memcached_continuum_item_st *)t1;
 117   memcached_continuum_item_st *ct2 = (memcached_continuum_item_st *)t2;
 118
 119   WATCHPOINT_ASSERT(ct1->value != 153);
 120   if (ct1->value == ct2->value)
 121     return 0;
 122   else if (ct1->value > ct2->value)
 123     return 1;
 124   else
 125     return -1;
 126 }
 127
 128 static uint32_t internal_generate_ketama_md5(char *key, size_t key_length)
 129 {
 130   unsigned char results[16];
 131
 132   md5_signature((unsigned char*)key, (unsigned int)key_length, results);
 133
 134   return ( (results[3] ) << 24)
 135     | ( (results[2] ) << 16)
 136     | ( (results[1] ) << 8)
 137     | ( results[0] );
 138 }
 139
 140 memcached_return update_continuum(memcached_st *ptr)
 141 {
 142   uint32_t index;
 143   uint32_t host_index;
 144   uint32_t continuum_index= 0;
 145   uint32_t value;
 146   memcached_server_st *list;
 147
 148   if (ptr->number_of_hosts > ptr->continuum_count)
 149   {
 150     memcached_continuum_item_st *new_ptr;
 151
 152     if (ptr->call_realloc)
 153       new_ptr= (memcached_continuum_item_st *)ptr->call_realloc(ptr, ptr->continuum, sizeof(memcached_continuum_item_st) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * MEMCACHED_POINTS_PER_SERVER);
 154     else
 155       new_ptr= (memcached_continuum_item_st *)realloc(ptr->continuum, sizeof(memcached_continuum_item_st) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * MEMCACHED_POINTS_PER_SERVER);
 156
 157     if (new_ptr == 0)
 158       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 159
 160     ptr->continuum= new_ptr;
 161     ptr->continuum_count= ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION;
 162   }
 163
 164   list = ptr->hosts;
 165   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 166   {
 167     for(index= 1; index <= MEMCACHED_POINTS_PER_SERVER; ++index)
 168     {
 169       char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 170       size_t sort_host_length;
 171
 172       sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH, "%s:%d-%d",
 173                                  list[host_index].hostname, list[host_index].port, index);
 174       WATCHPOINT_ASSERT(sort_host_length);
 175       value= internal_generate_ketama_md5(sort_host, sort_host_length);
 176       ptr->continuum[continuum_index].index= host_index;
 177       ptr->continuum[continuum_index++].value= value;
 178     }
 179   }
 180
 181   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 182   qsort(ptr->continuum, ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 183 #ifdef HAVE_DEBUG
 184   for (index= 0; index < ((ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER) - 1); index++)
 185   {
 186     WATCHPOINT_ASSERT(ptr->continuum[index].value <= ptr->continuum[index + 1].value);
 187   }
 188 #endif
 189
 190   return MEMCACHED_SUCCESS;
 191 }
 192
 193
 194 memcached_return memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 195 {
 196   unsigned int x;
 197   uint16_t count;
 198   memcached_server_st *new_host_list;
 199
 200   if (!list)
 201     return MEMCACHED_SUCCESS;
 202
 203   count= list[0].count;
 204
 205   if (ptr->call_realloc)
 206     new_host_list=
 207       (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 208                                                sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 209   else
 210     new_host_list=
 211       (memcached_server_st *)realloc(ptr->hosts,
 212                                      sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 213
 214   if (!new_host_list)
 215     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 216
 217   ptr->hosts= new_host_list;
 218
 219   for (x= 0; x < count; x++)
 220   {
 221     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 222     host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 223                list[x].port, list[x].type);
 224     ptr->number_of_hosts++;
 225   }
 226   ptr->hosts[0].count= ptr->number_of_hosts;
 227
 228   return run_distribution(ptr);
 229 }
 230
 231 memcached_return memcached_server_add_unix_socket(memcached_st *ptr, char *filename)
 232 {
 233   if (!filename)
 234     return MEMCACHED_FAILURE;
 235
 236   return server_add(ptr, filename, 0, MEMCACHED_CONNECTION_UNIX_SOCKET);
 237 }
 238
 239 memcached_return memcached_server_add_udp(memcached_st *ptr,
 240                                           char *hostname,
 241                                           unsigned int port)
 242 {
 243   if (!port)
 244     port= MEMCACHED_DEFAULT_PORT;
 245
 246   if (!hostname)
 247     hostname= "localhost";
 248
 249   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_UDP);
 250 }
 251
 252 memcached_return memcached_server_add(memcached_st *ptr,
 253                                       char *hostname,
 254                                       unsigned int port)
 255 {
 256   if (!port)
 257     port= MEMCACHED_DEFAULT_PORT;
 258
 259   if (!hostname)
 260     hostname= "localhost";
 261
 262   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_TCP);
 263 }
 264
 265 static memcached_return server_add(memcached_st *ptr, char *hostname,
 266                                    unsigned int port,
 267                                    memcached_connection type)
 268 {
 269   memcached_server_st *new_host_list;
 270
 271   if (ptr->call_realloc)
 272     new_host_list= (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 273                                                             sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 274   else
 275     new_host_list= (memcached_server_st *)realloc(ptr->hosts,
 276                                                   sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 277   if (new_host_list == NULL)
 278     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 279
 280   ptr->hosts= new_host_list;
 281
 282   host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, type);
 283   ptr->number_of_hosts++;
 284   ptr->hosts[0].count= ptr->number_of_hosts;
 285
 286   return run_distribution(ptr);
 287 }
 288
 289 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 290                                                   char *hostname, unsigned int port,
 291                                                   memcached_return *error)
 292 {
 293   unsigned int count;
 294   memcached_server_st *new_host_list;
 295
 296   if (hostname == NULL || error == NULL)
 297     return NULL;
 298
 299   if (!port)
 300     port= MEMCACHED_DEFAULT_PORT;
 301
 302   /* Increment count for hosts */
 303   count= 1;
 304   if (ptr != NULL)
 305   {
 306     count+= ptr[0].count;
 307   }
 308
 309   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 310   if (!new_host_list)
 311   {
 312     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 313     return NULL;
 314   }
 315
 316   host_reset(NULL, &new_host_list[count-1], hostname, port, MEMCACHED_CONNECTION_TCP);
 317
 318   /* Backwards compatibility hack */
 319   new_host_list[0].count= count;
 320
 321   *error= MEMCACHED_SUCCESS;
 322   return new_host_list;
 323 }
 324
 325 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 326 {
 327   if (ptr == NULL)
 328     return 0;
 329
 330   return ptr[0].count;
 331 }
 332
 333 void memcached_server_list_free(memcached_server_st *ptr)
 334 {
 335   server_list_free(NULL, ptr);
 336 }