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/* --- BEGIN COPYRIGHT BLOCK ---
* This Program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation; version 2 of the License.
*
* This Program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with
* this Program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place, Suite 330, Boston, MA 02111-1307 USA.
*
* In addition, as a special exception, Red Hat, Inc. gives You the additional
* right to link the code of this Program with code not covered under the GNU
* General Public License ("Non-GPL Code") and to distribute linked combinations
* including the two, subject to the limitations in this paragraph. Non-GPL Code
* permitted under this exception must only link to the code of this Program
* through those well defined interfaces identified in the file named EXCEPTION
* found in the source code files (the "Approved Interfaces"). The files of
* Non-GPL Code may instantiate templates or use macros or inline functions from
* the Approved Interfaces without causing the resulting work to be covered by
* the GNU General Public License. Only Red Hat, Inc. may make changes or
* additions to the list of Approved Interfaces. You must obey the GNU General
* Public License in all respects for all of the Program code and other code used
* in conjunction with the Program except the Non-GPL Code covered by this
* exception. If you modify this file, you may extend this exception to your
* version of the file, but you are not obligated to do so. If you do not wish to
* provide this exception without modification, you must delete this exception
* statement from your version and license this file solely under the GPL without
* exception.
*
*
* Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
* Copyright (C) 2005 Red Hat, Inc.
* All rights reserved.
* --- END COPYRIGHT BLOCK --- */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <ctype.h>
#include <string.h>
#include "slapi-plugin.h"
/*
* These are examples of distribution function as declared in mapping tree node
* This function will be called for every operations
* reaching this node, including subtree search operations that are started
* above this node
*
* Parameters :
* . pb is the pblock of the operation
* . target_dn is the target DN of the operation
* . mtn_be_names is the list of names of backends declared for this node
* . be_count is the number of backends declared
* . node_dn is the node where the distribution function is set
*
* The return value of the functions should be the indice of the backend
* in the mtn_be_names table
* For search operation, the value SLAPI_BE_ALL_BACKENDS can be used to
* specify that all backends must be searched
* The use of value SLAPI_BE_ALL_BACKENDS for operation other than search
* is not supported and may give random results
*
*/
/*
* Distribute the entries based on the first letter of their rdn
*
* . Entries starting with anything other that a-z or A-Z will always
* go in backend 0
* . Entries starting with letter (a-z or A-Z) will be shared between
* the backends depending following the alphabetic order
* Example : if 3 backends are used, entries starting with A-I will go
* in backend 0, entries starting with J-R will go in backend 1, entries
* starting with S-Z will go in backend 2
*
* Of course this won't work for all locales...
*
* This example only works for a flat namespace below the node DN
*/
int alpha_distribution(Slapi_PBlock *pb, Slapi_DN * target_dn,
char **mtn_be_names, int be_count, Slapi_DN * node_dn)
{
unsigned long op_type;
Slapi_Operation *op;
char *rdn_type;
char *rdn_value;
Slapi_RDN *rdn = NULL;
char c;
/* first check the operation type
* searches at node level or above it should go in all backends
* searches below node level should go in only one backend
*/
slapi_pblock_get(pb, SLAPI_OPERATION, &op);
op_type = slapi_op_get_type(op);
if ((op_type == SLAPI_OPERATION_SEARCH) &&
slapi_sdn_issuffix(node_dn, target_dn))
return SLAPI_BE_ALL_BACKENDS;
/* now choose the backend
* anything starting with a char different from a-z or A-Z will
* go in backend 0
*/
/* get the first char of first value of rdn */
rdn = slapi_rdn_new();
slapi_sdn_get_rdn(target_dn, rdn);
slapi_rdn_get_first(rdn, &rdn_type, &rdn_value);
c = rdn_value[0];
slapi_rdn_free(&rdn);
if (!(((c >= 'a') && (c <= 'z')) ||
((c >= 'A') && (c <= 'Z')) ))
{
return 0;
}
/* for entries with rdn starting with alphabetic characters
* use the formula : (c - 'A') * be_count/26
* to calculate the backend number
*/
return (toupper(c) - 'A') * be_count/26;
}
/*
* Distribute the entries based on a simple hash algorithme
*/
int hash_distribution(Slapi_PBlock *pb, Slapi_DN * target_dn,
char **mtn_be_names, int be_count, Slapi_DN * node_dn)
{
unsigned long op_type;
Slapi_Operation *op;
char *rdn_type;
char *rdn_value;
Slapi_RDN *rdn = NULL;
int hash_value;
/* first check the operation type
* searches at node level or above it should go in all backends
* searches below node level should go in only one backend
*/
slapi_pblock_get(pb, SLAPI_OPERATION, &op);
op_type = slapi_op_get_type(op);
if ((op_type == SLAPI_OPERATION_SEARCH) &&
slapi_sdn_issuffix(node_dn, target_dn))
return SLAPI_BE_ALL_BACKENDS;
/* now choose the backend
*/
/* get the rdn and hash it to compute the backend number
* use a simple hash for this example
*/
rdn = slapi_rdn_new();
slapi_sdn_get_rdn(target_dn, rdn);
slapi_rdn_get_first(rdn, &rdn_type, &rdn_value);
/* compute the hash value */
hash_value = 0;
while (*rdn_value)
{
hash_value += *rdn_value;
rdn_value++;
}
hash_value = hash_value % be_count;
slapi_rdn_free(&rdn);
/* use the hash_value as the returned backend number */
return hash_value;
}
/*
* This plugin allows to use a local backend in conjonction with
* a chaining backend
* The ldbm backend is considered a read-only replica of the data
* The chaining backend point to a red-write replica of the data
* This distribution logic forward the update request to the chaining
* backend, and send the search request to the local dbm database
*
* The mechanism for updating the local read-only replica is not
* taken into account by this plugin
*
* To be able to use it one must define one ldbm backend and one chaining
* backend in the mapping tree node
*
*/
int chaining_distribution(Slapi_PBlock *pb, Slapi_DN * target_dn,
char **mtn_be_names, int be_count, Slapi_DN * node_dn)
{
char * requestor_dn;
unsigned long op_type;
Slapi_Operation *op;
int repl_op = 0;
int local_backend = -1;
int chaining_backend = -1;
int i;
char * name;
/* first, we have to decide which backend is the local backend
* and which is the chaining one
* For the purpose of this example use the backend name :
* the backend with name starting with ldbm is local
* the bakend with name starting with chaining is remote
*/
local_backend = -1;
chaining_backend = -1;
for (i=0; i<be_count; i++)
{
name = mtn_be_names[i];
if ((0 == strncmp(name, "ldbm", 4)) ||
(0 == strncmp(name, "user", 4)))
local_backend = i;
else if (0 == strncmp(name, "chaining", 8))
chaining_backend = i;
}
/* Check the operation type
* read-only operation will go to the local backend
* updates operation will go to the chaining backend
*/
slapi_pblock_get(pb, SLAPI_OPERATION, &op);
op_type = slapi_op_get_type(op);
if ((op_type == SLAPI_OPERATION_SEARCH) ||
(op_type == SLAPI_OPERATION_BIND) ||
(op_type == SLAPI_OPERATION_UNBIND) ||
(op_type == SLAPI_OPERATION_COMPARE))
return local_backend;
/* if the operation is done by directory manager
* use local database even for updates because it is an administrative
* operation
* remarks : one could also use an update DN in the same way
* to let update operation go to the local backend when they are done
* by specific administrator user but let all the other user
* go to the read-write replica
*/
slapi_pblock_get( pb, SLAPI_REQUESTOR_DN, &requestor_dn );
if (slapi_dn_isroot(requestor_dn))
return local_backend;
/* if the operation is a replicated operation
* use local database even for updates to avoid infinite loops
*/
slapi_pblock_get (pb, SLAPI_IS_REPLICATED_OPERATION, &repl_op);
if (repl_op)
return local_backend;
/* all other case (update while not directory manager) :
* use the chaining backend
*/
return chaining_backend;
}
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