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 memcached_return update_continuum(memcached_st *ptr);
   8
   9 #define MEMCACHED_WHEEL_SIZE 1024
  10 #define MEMCACHED_STRIDE 4
  11 static memcached_return rebalance_wheel(memcached_st *ptr)
  12 {
  13   unsigned int x;
  14   unsigned int y;
  15   unsigned int latch;
  16
  17   if (ptr->number_of_hosts > ptr->wheel_count)
  18   {
  19     uint32_t *new_ptr;
  20
  21     if (ptr->call_realloc)
  22       new_ptr= (uint32_t *)ptr->call_realloc(ptr, ptr->wheel, sizeof(uint32_t) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * MEMCACHED_STRIDE);
  23     else
  24       new_ptr= (uint32_t *)realloc(ptr->wheel, sizeof(uint32_t) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * MEMCACHED_STRIDE);
  25
  26     if (new_ptr == 0)
  27       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
  28
  29     ptr->wheel= new_ptr;
  30     ptr->wheel_count= ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION;
  31   }
  32
  33   /* Seed the Wheel */
  34   memset(ptr->wheel, 0, sizeof(uint32_t) * MEMCACHED_STRIDE * ptr->wheel_count);
  35
  36   for (latch= y= x= 0; x < MEMCACHED_STRIDE * ptr->wheel_count; x++, latch++)
  37   {
  38     if (latch == MEMCACHED_STRIDE)
  39     {
  40       y++;
  41       if (y == ptr->number_of_hosts)
  42         y= 0;
  43       latch= 0;
  44     }
  45
  46     ptr->wheel[x]= y;
  47   }
  48
  49   return MEMCACHED_SUCCESS;
  50 }
  51
  52 static int compare_servers(const void *p1, const void *p2)
  53 {
  54   int return_value;
  55   memcached_server_st *a= (memcached_server_st *)p1;
  56   memcached_server_st *b= (memcached_server_st *)p2;
  57
  58   return_value= strcmp(a->hostname, b->hostname);
  59
  60   if (return_value == 0)
  61   {
  62     return_value= (int) (a->port - b->port);
  63   }
  64
  65   return return_value;
  66 }
  67
  68 void sort_hosts(memcached_st *ptr)
  69 {
  70   if (ptr->number_of_hosts)
  71   {
  72     qsort(ptr->hosts, ptr->number_of_hosts, sizeof(memcached_server_st), compare_servers);
  73     ptr->hosts[0].count= ptr->number_of_hosts;
  74   }
  75 }
  76
  77
  78 memcached_return run_distribution(memcached_st *ptr)
  79 {
  80   switch (ptr->distribution)
  81   {
  82   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  83   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  84     return update_continuum(ptr);
  85   case MEMCACHED_DISTRIBUTION_CONSISTENT_WHEEL:
  86     return rebalance_wheel(ptr);
  87     break;
  88   case MEMCACHED_DISTRIBUTION_MODULA:
  89     if (ptr->flags & MEM_USE_SORT_HOSTS)
  90       sort_hosts(ptr);
  91     break;
  92   default:
  93     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  94   }
  95
  96   return MEMCACHED_SUCCESS;
  97 }
  98
  99 static void host_reset(memcached_st *ptr, memcached_server_st *host,
 100                        char *hostname, unsigned int port,
 101                        memcached_connection type)
 102 {
 103   memset(host,  0, sizeof(memcached_server_st));
 104   strncpy(host->hostname, hostname, MEMCACHED_MAX_HOST_LENGTH - 1);
 105   host->root= ptr ? ptr : NULL;
 106   host->port= port;
 107   host->fd= -1;
 108   host->type= type;
 109   host->read_ptr= host->read_buffer;
 110   if (ptr)
 111     host->next_retry= ptr->retry_timeout;
 112   host->sockaddr_inited= MEMCACHED_NOT_ALLOCATED;
 113 }
 114
 115 void server_list_free(memcached_st *ptr, memcached_server_st *servers)
 116 {
 117   unsigned int x;
 118
 119   if (servers == NULL)
 120     return;
 121
 122   for (x= 0; x < servers->count; x++)
 123     if (servers[x].address_info)
 124       freeaddrinfo(servers[x].address_info);
 125
 126   if (ptr && ptr->call_free)
 127     ptr->call_free(ptr, servers);
 128   else
 129     free(servers);
 130 }
 131
 132 static int continuum_item_cmp(const void *t1, const void *t2)
 133 {
 134   memcached_continuum_item_st *ct1 = (memcached_continuum_item_st *)t1;
 135   memcached_continuum_item_st *ct2 = (memcached_continuum_item_st *)t2;
 136
 137   WATCHPOINT_ASSERT(ct1->value != 153);
 138   if (ct1->value == ct2->value)
 139     return 0;
 140   else if (ct1->value > ct2->value)
 141     return 1;
 142   else
 143     return -1;
 144 }
 145
 146 static uint32_t internal_generate_ketama_md5(char *key, size_t key_length)
 147 {
 148   unsigned char results[16];
 149
 150   md5_signature((unsigned char*)key, (unsigned int)key_length, results);
 151
 152   return ( (results[3] ) << 24)
 153     | ( (results[2] ) << 16)
 154     | ( (results[1] ) << 8)
 155     | ( results[0] );
 156 }
 157
 158 memcached_return update_continuum(memcached_st *ptr)
 159 {
 160   uint32_t index;
 161   uint32_t host_index;
 162   uint32_t continuum_index= 0;
 163   uint32_t value;
 164   memcached_server_st *list;
 165
 166   if (ptr->number_of_hosts > ptr->continuum_count)
 167   {
 168     memcached_continuum_item_st *new_ptr;
 169
 170     if (ptr->call_realloc)
 171       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);
 172     else
 173       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);
 174
 175     if (new_ptr == 0)
 176       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 177
 178     ptr->continuum= new_ptr;
 179     ptr->continuum_count= ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION;
 180   }
 181
 182   list = ptr->hosts;
 183   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 184   {
 185     for(index= 1; index <= MEMCACHED_POINTS_PER_SERVER; ++index)
 186     {
 187       char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 188       size_t sort_host_length;
 189
 190       sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH, "%s:%d-%d",
 191                                  list[host_index].hostname, list[host_index].port, index);
 192       WATCHPOINT_ASSERT(sort_host_length);
 193       value= internal_generate_ketama_md5(sort_host, sort_host_length);
 194       ptr->continuum[continuum_index].index= host_index;
 195       ptr->continuum[continuum_index++].value= value;
 196     }
 197   }
 198
 199   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 200   qsort(ptr->continuum, ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 201 #ifdef HAVE_DEBUG
 202   for (index= 0; index < ((ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER) - 1); index++)
 203   {
 204     WATCHPOINT_ASSERT(ptr->continuum[index].value <= ptr->continuum[index + 1].value);
 205   }
 206 #endif
 207
 208   return MEMCACHED_SUCCESS;
 209 }
 210
 211
 212 memcached_return memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 213 {
 214   unsigned int x;
 215   uint16_t count;
 216   memcached_server_st *new_host_list;
 217
 218   if (!list)
 219     return MEMCACHED_SUCCESS;
 220
 221   count= list[0].count;
 222
 223   if (ptr->call_realloc)
 224     new_host_list=
 225       (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 226                                                sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 227   else
 228     new_host_list=
 229       (memcached_server_st *)realloc(ptr->hosts,
 230                                      sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 231
 232   if (!new_host_list)
 233     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 234
 235   ptr->hosts= new_host_list;
 236
 237   for (x= 0; x < count; x++)
 238   {
 239     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 240     host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 241                list[x].port, list[x].type);
 242     ptr->number_of_hosts++;
 243   }
 244   ptr->hosts[0].count= ptr->number_of_hosts;
 245
 246   return run_distribution(ptr);
 247 }
 248
 249 memcached_return memcached_server_add_unix_socket(memcached_st *ptr, char *filename)
 250 {
 251   if (!filename)
 252     return MEMCACHED_FAILURE;
 253
 254   return server_add(ptr, filename, 0, MEMCACHED_CONNECTION_UNIX_SOCKET);
 255 }
 256
 257 memcached_return memcached_server_add_udp(memcached_st *ptr,
 258                                           char *hostname,
 259                                           unsigned int port)
 260 {
 261   if (!port)
 262     port= MEMCACHED_DEFAULT_PORT;
 263
 264   if (!hostname)
 265     hostname= "localhost";
 266
 267   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_UDP);
 268 }
 269
 270 memcached_return memcached_server_add(memcached_st *ptr,
 271                                       char *hostname,
 272                                       unsigned int port)
 273 {
 274   if (!port)
 275     port= MEMCACHED_DEFAULT_PORT;
 276
 277   if (!hostname)
 278     hostname= "localhost";
 279
 280   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_TCP);
 281 }
 282
 283 static memcached_return server_add(memcached_st *ptr, char *hostname,
 284                                    unsigned int port,
 285                                    memcached_connection type)
 286 {
 287   memcached_server_st *new_host_list;
 288
 289   if (ptr->call_realloc)
 290     new_host_list= (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 291                                                             sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 292   else
 293     new_host_list= (memcached_server_st *)realloc(ptr->hosts,
 294                                                   sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 295   if (new_host_list == NULL)
 296     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 297
 298   ptr->hosts= new_host_list;
 299
 300   host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, type);
 301   ptr->number_of_hosts++;
 302   ptr->hosts[0].count= ptr->number_of_hosts;
 303
 304   return run_distribution(ptr);
 305 }
 306
 307 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 308                                                   char *hostname, unsigned int port,
 309                                                   memcached_return *error)
 310 {
 311   unsigned int count;
 312   memcached_server_st *new_host_list;
 313
 314   if (hostname == NULL || error == NULL)
 315     return NULL;
 316
 317   if (!port)
 318     port= MEMCACHED_DEFAULT_PORT;
 319
 320   /* Increment count for hosts */
 321   count= 1;
 322   if (ptr != NULL)
 323   {
 324     count+= ptr[0].count;
 325   }
 326
 327   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 328   if (!new_host_list)
 329   {
 330     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 331     return NULL;
 332   }
 333
 334   host_reset(NULL, &new_host_list[count-1], hostname, port, MEMCACHED_CONNECTION_TCP);
 335
 336   /* Backwards compatibility hack */
 337   new_host_list[0].count= count;
 338
 339   *error= MEMCACHED_SUCCESS;
 340   return new_host_list;
 341 }
 342
 343 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 344 {
 345   if (ptr == NULL)
 346     return 0;
 347
 348   return ptr[0].count;
 349 }
 350
 351 void memcached_server_list_free(memcached_server_st *ptr)
 352 {
 353   server_list_free(NULL, ptr);
 354 }