src/libcharon/plugins/attr_sql/attr_sql_provider.c - manifest_repos/strongswan - Git at Google

 /*
  * Copyright (C) 2008 Martin Willi
  * HSR Hochschule fuer Technik Rapperswil
  *
  * 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; either version 2 of the License, or (at your
  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  *
  * 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.
  */

 #include <time.h>

 #include <utils/debug.h>
 #include <library.h>

 #include "attr_sql_provider.h"

 typedef struct private_attr_sql_provider_t private_attr_sql_provider_t;

 /**
  * private data of attr_sql_provider
  */
 struct private_attr_sql_provider_t {

 	/**
 	 * public functions
 	 */
 	attr_sql_provider_t public;

 	/**
 	 * database connection
 	 */
 	database_t *db;

 	/**
 	 * whether to record lease history in lease table
 	 */
 	bool history;
 };

 /**
  * lookup/insert an identity
  */
 static u_int get_identity(private_attr_sql_provider_t *this, ike_sa_t *ike_sa)
 {
 	identification_t *id;
 	enumerator_t *e;
 	u_int row;

 	id = ike_sa->get_other_eap_id(ike_sa);

 	this->db->transaction(this->db, TRUE);
 	/* look for peer identity in the identities table */
 	e = this->db->query(this->db,
 						"SELECT id FROM identities WHERE type = ? AND data = ?",
 						DB_INT, id->get_type(id), DB_BLOB, id->get_encoding(id),
 						DB_UINT);
 	if (e && e->enumerate(e, &row))
 	{
 		e->destroy(e);
 		this->db->commit(this->db);
 		return row;
 	}
 	DESTROY_IF(e);
 	/* not found, insert new one */
 	if (this->db->execute(this->db, &row,
 				  "INSERT INTO identities (type, data) VALUES (?, ?)",
 				  DB_INT, id->get_type(id), DB_BLOB, id->get_encoding(id)) == 1)
 	{
 		this->db->commit(this->db);
 		return row;
 	}
 	this->db->rollback(this->db);
 	return 0;
 }

 /**
  * Lookup an attribute pool by name
  */
 static u_int get_attr_pool(private_attr_sql_provider_t *this, char *name)
 {
 	enumerator_t *e;
 	u_int row = 0;

 	e = this->db->query(this->db,
 						"SELECT id FROM attribute_pools WHERE name = ?",
 						DB_TEXT, name, DB_UINT);
 	if (e)
 	{
 		e->enumerate(e, &row);
 	}
 	DESTROY_IF(e);

 	return row;
 }

 /**
  * Lookup pool by name and address family
  */
 static u_int get_pool(private_attr_sql_provider_t *this, char *name, int family,
 					  u_int *timeout)
 {
 	enumerator_t *e;
 	chunk_t start;
 	u_int pool;

 	e = this->db->query(this->db,
 						"SELECT id, start, timeout FROM pools WHERE name = ?",
 						DB_TEXT, name, DB_UINT, DB_BLOB, DB_UINT);
 	if (e && e->enumerate(e, &pool, &start, timeout))
 	{
 		if ((family == AF_INET  && start.len == 4) ||
 			(family == AF_INET6 && start.len == 16))
 		{
 			e->destroy(e);
 			return pool;
 		}
 	}
 	DESTROY_IF(e);
 	return 0;
 }

 /**
  * Look up an existing lease
  */
 static host_t* check_lease(private_attr_sql_provider_t *this, char *name,
 						   u_int pool, u_int identity)
 {
 	while (TRUE)
 	{
 		u_int id;
 		chunk_t address;
 		enumerator_t *e;
 		time_t now = time(NULL);

 		e = this->db->query(this->db,
 				"SELECT id, address FROM addresses "
 				"WHERE pool = ? AND identity = ? AND released != 0 LIMIT 1",
 				DB_UINT, pool, DB_UINT, identity, DB_UINT, DB_BLOB);
 		if (!e || !e->enumerate(e, &id, &address))
 		{
 			DESTROY_IF(e);
 			break;
 		}
 		address = chunk_clonea(address);
 		e->destroy(e);

 		if (this->db->execute(this->db, NULL,
 				"UPDATE addresses SET acquired = ?, released = 0 "
 				"WHERE id = ? AND identity = ? AND released != 0",
 				DB_UINT, now, DB_UINT, id, DB_UINT, identity) > 0)
 		{
 			host_t *host;

 			host = host_create_from_chunk(AF_UNSPEC, address, 0);
 			if (host)
 			{
 				DBG1(DBG_CFG, "acquired existing lease for address %H in"
 					 " pool '%s'", host, name);
 				return host;
 			}
 		}
 	}
 	return NULL;
 }

 /**
  * We check for unallocated addresses or expired leases. First we select an
  * address as a candidate, but double check later on if it is still available
  * during the update operation. This allows us to work without locking.
  */
 static host_t* get_lease(private_attr_sql_provider_t *this, char *name,
 						 u_int pool, u_int timeout, u_int identity)
 {
 	while (TRUE)
 	{
 		u_int id;
 		chunk_t address;
 		enumerator_t *e;
 		time_t now = time(NULL);
 		int hits;

 		if (timeout)
 		{
 			/* check for an expired lease */
 			e = this->db->query(this->db,
 				"SELECT id, address FROM addresses "
 				"WHERE pool = ? AND released != 0 AND released < ? LIMIT 1",
 				DB_UINT, pool, DB_UINT, now - timeout, DB_UINT, DB_BLOB);
 		}
 		else
 		{
 			/* with static leases, check for an unallocated address */
 			e = this->db->query(this->db,
 				"SELECT id, address FROM addresses "
 				"WHERE pool = ? AND identity = 0 LIMIT 1",
 				DB_UINT, pool, DB_UINT, DB_BLOB);
 		}

 		if (!e || !e->enumerate(e, &id, &address))
 		{
 			DESTROY_IF(e);
 			break;
 		}
 		address = chunk_clonea(address);
 		e->destroy(e);

 		if (timeout)
 		{
 			hits = this->db->execute(this->db, NULL,
 						"UPDATE addresses SET "
 						"acquired = ?, released = 0, identity = ? "
 						"WHERE id = ? AND released != 0 AND released < ?",
 						DB_UINT, now, DB_UINT, identity,
 						DB_UINT, id, DB_UINT, now - timeout);
 		}
 		else
 		{
 			hits = this->db->execute(this->db, NULL,
 						"UPDATE addresses SET "
 						"acquired = ?, released = 0, identity = ? "
 						"WHERE id = ? AND identity = 0",
 						DB_UINT, now, DB_UINT, identity, DB_UINT, id);
 		}
 		if (hits > 0)
 		{
 			host_t *host;

 			host = host_create_from_chunk(AF_UNSPEC, address, 0);
 			if (host)
 			{
 				DBG1(DBG_CFG, "acquired new lease for address %H in pool '%s'",
 					 host, name);
 				return host;
 			}
 		}
 	}
 	DBG1(DBG_CFG, "no available address found in pool '%s'", name);
 	return NULL;
 }

 METHOD(attribute_provider_t, acquire_address, host_t*,
 	private_attr_sql_provider_t *this, linked_list_t *pools, ike_sa_t *ike_sa,
 	host_t *requested)
 {
 	enumerator_t *enumerator;
 	host_t *address = NULL;
 	u_int identity, pool, timeout;
 	char *name;
 	int family;

 	identity = get_identity(this, ike_sa);
 	if (identity)
 	{
 		family = requested->get_family(requested);
 		/* check for an existing lease in all pools */
 		enumerator = pools->create_enumerator(pools);
 		while (enumerator->enumerate(enumerator, &name))
 		{
 			pool = get_pool(this, name, family, &timeout);
 			if (pool)
 			{
 				address = check_lease(this, name, pool, identity);
 				if (address)
 				{
 					break;
 				}
 			}
 		}
 		enumerator->destroy(enumerator);

 		if (!address)
 		{
 			/* get an unallocated address or expired lease */
 			enumerator = pools->create_enumerator(pools);
 			while (enumerator->enumerate(enumerator, &name))
 			{
 				pool = get_pool(this, name, family, &timeout);
 				if (pool)
 				{
 					address = get_lease(this, name, pool, timeout, identity);
 					if (address)
 					{
 						break;
 					}
 				}
 			}
 			enumerator->destroy(enumerator);
 		}
 	}
 	return address;
 }

 METHOD(attribute_provider_t, release_address, bool,
 	private_attr_sql_provider_t *this, linked_list_t *pools, host_t *address,
 	ike_sa_t *ike_sa)
 {
 	enumerator_t *enumerator;
 	u_int pool, timeout;
 	time_t now = time(NULL);
 	bool found = FALSE;
 	char *name;
 	int family;

 	family = address->get_family(address);
 	enumerator = pools->create_enumerator(pools);
 	while (enumerator->enumerate(enumerator, &name))
 	{
 		pool = get_pool(this, name, family, &timeout);
 		if (!pool)
 		{
 			continue;
 		}
 		if (this->db->execute(this->db, NULL,
 				"UPDATE addresses SET released = ? WHERE "
 				"pool = ? AND address = ?", DB_UINT, time(NULL),
 				DB_UINT, pool, DB_BLOB, address->get_address(address)) > 0)
 		{
 			if (this->history)
 			{
 				this->db->execute(this->db, NULL,
 					"INSERT INTO leases (address, identity, acquired, released)"
 					" SELECT id, identity, acquired, ? FROM addresses "
 					" WHERE pool = ? AND address = ?",
 					DB_UINT, now, DB_UINT, pool,
 					DB_BLOB, address->get_address(address));
 			}
 			found = TRUE;
 			break;
 		}
 	}
 	enumerator->destroy(enumerator);

 	return found;
 }

 METHOD(attribute_provider_t, create_attribute_enumerator, enumerator_t*,
 	private_attr_sql_provider_t *this, linked_list_t *pools, ike_sa_t *ike_sa,
 	linked_list_t *vips)
 {
 	enumerator_t *attr_enumerator = NULL;

 	if (vips->get_count(vips))
 	{
 		enumerator_t *pool_enumerator;
 		u_int count;
 		char *name;

 		/* in a first step check for attributes that match name and id */
 		if (ike_sa)
 		{
 			u_int identity = get_identity(this, ike_sa);

 			pool_enumerator = pools->create_enumerator(pools);
 			while (pool_enumerator->enumerate(pool_enumerator, &name))
 			{
 				u_int attr_pool = get_attr_pool(this, name);
 				if (!attr_pool)
 				{
 					continue;
 				}

 				attr_enumerator = this->db->query(this->db,
 								"SELECT count(*) FROM attributes "
 								"WHERE pool = ? AND identity = ?",
 								DB_UINT, attr_pool, DB_UINT, identity, DB_UINT);

 				if (attr_enumerator &&
 					attr_enumerator->enumerate(attr_enumerator, &count) &&
 					count != 0)
 				{
 					attr_enumerator->destroy(attr_enumerator);
 					attr_enumerator = this->db->query(this->db,
 								"SELECT type, value FROM attributes "
 								"WHERE pool = ? AND identity = ?", DB_UINT,
 								attr_pool, DB_UINT, identity, DB_INT, DB_BLOB);
 					break;
 				}
 				DESTROY_IF(attr_enumerator);
 				attr_enumerator = NULL;
 			}
 			pool_enumerator->destroy(pool_enumerator);
 		}

 		/* in a second step check for attributes that match name */
 		if (!attr_enumerator)
 		{
 			pool_enumerator = pools->create_enumerator(pools);
 			while (pool_enumerator->enumerate(pool_enumerator, &name))
 			{
 				u_int attr_pool = get_attr_pool(this, name);
 				if (!attr_pool)
 				{
 					continue;
 				}

 				attr_enumerator = this->db->query(this->db,
 									"SELECT count(*) FROM attributes "
 									"WHERE pool = ? AND identity = 0",
 									DB_UINT, attr_pool, DB_UINT);

 				if (attr_enumerator &&
 					attr_enumerator->enumerate(attr_enumerator, &count) &&
 					count != 0)
 				{
 					attr_enumerator->destroy(attr_enumerator);
 					attr_enumerator = this->db->query(this->db,
 									"SELECT type, value FROM attributes "
 									"WHERE pool = ? AND identity = 0",
 									DB_UINT, attr_pool, DB_INT, DB_BLOB);
 					break;
 				}
 				DESTROY_IF(attr_enumerator);
 				attr_enumerator = NULL;
 			}
 			pool_enumerator->destroy(pool_enumerator);
 		}

 		/* lastly try to find global attributes */
 		if (!attr_enumerator)
 		{
 			attr_enumerator = this->db->query(this->db,
 									"SELECT type, value FROM attributes "
 									"WHERE pool = 0 AND identity = 0",
 									DB_INT, DB_BLOB);
 		}
 	}

 	return (attr_enumerator ? attr_enumerator : enumerator_create_empty());
 }

 METHOD(attr_sql_provider_t, destroy, void,
 	private_attr_sql_provider_t *this)
 {
 	free(this);
 }

 /*
  * see header file
  */
 attr_sql_provider_t *attr_sql_provider_create(database_t *db)
 {
 	private_attr_sql_provider_t *this;

 	INIT(this,
 		.public = {
 			.provider = {
 				.acquire_address = _acquire_address,
 				.release_address = _release_address,
 				.create_attribute_enumerator = _create_attribute_enumerator,
 			},
 			.destroy = _destroy,
 		},
 		.db = db,
 		.history = lib->settings->get_bool(lib->settings,
 						"%s.plugins.attr-sql.lease_history", TRUE, lib->ns),
 	);

 	if (lib->settings->get_bool(lib->settings,
 						"%s.plugins.attr-sql.crash_recovery", TRUE, lib->ns))
 	{
 		time_t now = time(NULL);

 		/* close any "online" leases in the case we crashed */
 		if (this->history)
 		{
 			this->db->execute(this->db, NULL,
 					"INSERT INTO leases (address, identity, acquired, released)"
 					" SELECT id, identity, acquired, ? FROM addresses "
 					" WHERE released = 0", DB_UINT, now);
 		}
 		this->db->execute(this->db, NULL,
 					  "UPDATE addresses SET released = ? WHERE released = 0",
 					  DB_UINT, now);
 	}
 	return &this->public;
 }
	/*
	* Copyright (C) 2008 Martin Willi
	* HSR Hochschule fuer Technik Rapperswil
	*
	* 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; either version 2 of the License, or (at your
	* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
	*
	* 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.
	*/

	#include <time.h>

	#include <utils/debug.h>
	#include <library.h>

	#include "attr_sql_provider.h"

	typedef struct private_attr_sql_provider_t private_attr_sql_provider_t;

	/**
	* private data of attr_sql_provider
	*/
	struct private_attr_sql_provider_t {

	/**
	* public functions
	*/
	attr_sql_provider_t public;

	/**
	* database connection
	*/
	database_t *db;

	/**
	* whether to record lease history in lease table
	*/
	bool history;
	};

	/**
	* lookup/insert an identity
	*/
	static u_int get_identity(private_attr_sql_provider_t this, ike_sa_t ike_sa)
	{
	identification_t *id;
	enumerator_t *e;
	u_int row;

	id = ike_sa->get_other_eap_id(ike_sa);

	this->db->transaction(this->db, TRUE);
	/* look for peer identity in the identities table */
	e = this->db->query(this->db,
	"SELECT id FROM identities WHERE type = ? AND data = ?",
	DB_INT, id->get_type(id), DB_BLOB, id->get_encoding(id),
	DB_UINT);
	if (e && e->enumerate(e, &row))
	{
	e->destroy(e);
	this->db->commit(this->db);
	return row;
	}
	DESTROY_IF(e);
	/* not found, insert new one */
	if (this->db->execute(this->db, &row,
	"INSERT INTO identities (type, data) VALUES (?, ?)",
	DB_INT, id->get_type(id), DB_BLOB, id->get_encoding(id)) == 1)
	{
	this->db->commit(this->db);
	return row;
	}
	this->db->rollback(this->db);
	return 0;
	}

	/**
	* Lookup an attribute pool by name
	*/
	static u_int get_attr_pool(private_attr_sql_provider_t this, char name)
	{
	enumerator_t *e;
	u_int row = 0;

	e = this->db->query(this->db,
	"SELECT id FROM attribute_pools WHERE name = ?",
	DB_TEXT, name, DB_UINT);
	if (e)
	{
	e->enumerate(e, &row);
	}
	DESTROY_IF(e);

	return row;
	}

	/**
	* Lookup pool by name and address family
	*/
	static u_int get_pool(private_attr_sql_provider_t this, char name, int family,
	u_int *timeout)
	{
	enumerator_t *e;
	chunk_t start;
	u_int pool;

	e = this->db->query(this->db,
	"SELECT id, start, timeout FROM pools WHERE name = ?",
	DB_TEXT, name, DB_UINT, DB_BLOB, DB_UINT);
	if (e && e->enumerate(e, &pool, &start, timeout))
	{
	if ((family == AF_INET && start.len == 4) \|\|
	(family == AF_INET6 && start.len == 16))
	{
	e->destroy(e);
	return pool;
	}
	}
	DESTROY_IF(e);
	return 0;
	}

	/**
	* Look up an existing lease
	*/
	static host_t* check_lease(private_attr_sql_provider_t this, char name,
	u_int pool, u_int identity)
	{
	while (TRUE)
	{
	u_int id;
	chunk_t address;
	enumerator_t *e;
	time_t now = time(NULL);

	e = this->db->query(this->db,
	"SELECT id, address FROM addresses "
	"WHERE pool = ? AND identity = ? AND released != 0 LIMIT 1",
	DB_UINT, pool, DB_UINT, identity, DB_UINT, DB_BLOB);
	if (!e \|\| !e->enumerate(e, &id, &address))
	{
	DESTROY_IF(e);
	break;
	}
	address = chunk_clonea(address);
	e->destroy(e);

	if (this->db->execute(this->db, NULL,
	"UPDATE addresses SET acquired = ?, released = 0 "
	"WHERE id = ? AND identity = ? AND released != 0",
	DB_UINT, now, DB_UINT, id, DB_UINT, identity) > 0)
	{
	host_t *host;

	host = host_create_from_chunk(AF_UNSPEC, address, 0);
	if (host)
	{
	DBG1(DBG_CFG, "acquired existing lease for address %H in"
	" pool '%s'", host, name);
	return host;
	}
	}
	}
	return NULL;
	}

	/**
	* We check for unallocated addresses or expired leases. First we select an
	* address as a candidate, but double check later on if it is still available
	* during the update operation. This allows us to work without locking.
	*/
	static host_t* get_lease(private_attr_sql_provider_t this, char name,
	u_int pool, u_int timeout, u_int identity)
	{
	while (TRUE)
	{
	u_int id;
	chunk_t address;
	enumerator_t *e;
	time_t now = time(NULL);
	int hits;

	if (timeout)
	{
	/* check for an expired lease */
	e = this->db->query(this->db,
	"SELECT id, address FROM addresses "
	"WHERE pool = ? AND released != 0 AND released < ? LIMIT 1",
	DB_UINT, pool, DB_UINT, now - timeout, DB_UINT, DB_BLOB);
	}
	else
	{
	/* with static leases, check for an unallocated address */
	e = this->db->query(this->db,
	"SELECT id, address FROM addresses "
	"WHERE pool = ? AND identity = 0 LIMIT 1",
	DB_UINT, pool, DB_UINT, DB_BLOB);
	}

	if (!e \|\| !e->enumerate(e, &id, &address))
	{
	DESTROY_IF(e);
	break;
	}
	address = chunk_clonea(address);
	e->destroy(e);

	if (timeout)
	{
	hits = this->db->execute(this->db, NULL,
	"UPDATE addresses SET "
	"acquired = ?, released = 0, identity = ? "
	"WHERE id = ? AND released != 0 AND released < ?",
	DB_UINT, now, DB_UINT, identity,
	DB_UINT, id, DB_UINT, now - timeout);
	}
	else
	{
	hits = this->db->execute(this->db, NULL,
	"UPDATE addresses SET "
	"acquired = ?, released = 0, identity = ? "
	"WHERE id = ? AND identity = 0",
	DB_UINT, now, DB_UINT, identity, DB_UINT, id);
	}
	if (hits > 0)
	{
	host_t *host;

	host = host_create_from_chunk(AF_UNSPEC, address, 0);
	if (host)
	{
	DBG1(DBG_CFG, "acquired new lease for address %H in pool '%s'",
	host, name);
	return host;
	}
	}
	}
	DBG1(DBG_CFG, "no available address found in pool '%s'", name);
	return NULL;
	}

	METHOD(attribute_provider_t, acquire_address, host_t*,
	private_attr_sql_provider_t this, linked_list_t pools, ike_sa_t *ike_sa,
	host_t *requested)
	{
	enumerator_t *enumerator;
	host_t *address = NULL;
	u_int identity, pool, timeout;
	char *name;
	int family;

	identity = get_identity(this, ike_sa);
	if (identity)
	{
	family = requested->get_family(requested);
	/* check for an existing lease in all pools */
	enumerator = pools->create_enumerator(pools);
	while (enumerator->enumerate(enumerator, &name))
	{
	pool = get_pool(this, name, family, &timeout);
	if (pool)
	{
	address = check_lease(this, name, pool, identity);
	if (address)
	{
	break;
	}
	}
	}
	enumerator->destroy(enumerator);

	if (!address)
	{
	/* get an unallocated address or expired lease */
	enumerator = pools->create_enumerator(pools);
	while (enumerator->enumerate(enumerator, &name))
	{
	pool = get_pool(this, name, family, &timeout);
	if (pool)
	{
	address = get_lease(this, name, pool, timeout, identity);
	if (address)
	{
	break;
	}
	}
	}
	enumerator->destroy(enumerator);
	}
	}
	return address;
	}

	METHOD(attribute_provider_t, release_address, bool,
	private_attr_sql_provider_t this, linked_list_t pools, host_t *address,
	ike_sa_t *ike_sa)
	{
	enumerator_t *enumerator;
	u_int pool, timeout;
	time_t now = time(NULL);
	bool found = FALSE;
	char *name;
	int family;

	family = address->get_family(address);
	enumerator = pools->create_enumerator(pools);
	while (enumerator->enumerate(enumerator, &name))
	{
	pool = get_pool(this, name, family, &timeout);
	if (!pool)
	{
	continue;
	}
	if (this->db->execute(this->db, NULL,
	"UPDATE addresses SET released = ? WHERE "
	"pool = ? AND address = ?", DB_UINT, time(NULL),
	DB_UINT, pool, DB_BLOB, address->get_address(address)) > 0)
	{
	if (this->history)
	{
	this->db->execute(this->db, NULL,
	"INSERT INTO leases (address, identity, acquired, released)"
	" SELECT id, identity, acquired, ? FROM addresses "
	" WHERE pool = ? AND address = ?",
	DB_UINT, now, DB_UINT, pool,
	DB_BLOB, address->get_address(address));
	}
	found = TRUE;
	break;
	}
	}
	enumerator->destroy(enumerator);

	return found;
	}

	METHOD(attribute_provider_t, create_attribute_enumerator, enumerator_t*,
	private_attr_sql_provider_t this, linked_list_t pools, ike_sa_t *ike_sa,
	linked_list_t *vips)
	{
	enumerator_t *attr_enumerator = NULL;

	if (vips->get_count(vips))
	{
	enumerator_t *pool_enumerator;
	u_int count;
	char *name;

	/* in a first step check for attributes that match name and id */
	if (ike_sa)
	{
	u_int identity = get_identity(this, ike_sa);

	pool_enumerator = pools->create_enumerator(pools);
	while (pool_enumerator->enumerate(pool_enumerator, &name))
	{
	u_int attr_pool = get_attr_pool(this, name);
	if (!attr_pool)
	{
	continue;
	}

	attr_enumerator = this->db->query(this->db,
	"SELECT count(*) FROM attributes "
	"WHERE pool = ? AND identity = ?",
	DB_UINT, attr_pool, DB_UINT, identity, DB_UINT);

	if (attr_enumerator &&
	attr_enumerator->enumerate(attr_enumerator, &count) &&
	count != 0)
	{
	attr_enumerator->destroy(attr_enumerator);
	attr_enumerator = this->db->query(this->db,
	"SELECT type, value FROM attributes "
	"WHERE pool = ? AND identity = ?", DB_UINT,
	attr_pool, DB_UINT, identity, DB_INT, DB_BLOB);
	break;
	}
	DESTROY_IF(attr_enumerator);
	attr_enumerator = NULL;
	}
	pool_enumerator->destroy(pool_enumerator);
	}

	/* in a second step check for attributes that match name */
	if (!attr_enumerator)
	{
	pool_enumerator = pools->create_enumerator(pools);
	while (pool_enumerator->enumerate(pool_enumerator, &name))
	{
	u_int attr_pool = get_attr_pool(this, name);
	if (!attr_pool)
	{
	continue;
	}

	attr_enumerator = this->db->query(this->db,
	"SELECT count(*) FROM attributes "
	"WHERE pool = ? AND identity = 0",
	DB_UINT, attr_pool, DB_UINT);

	if (attr_enumerator &&
	attr_enumerator->enumerate(attr_enumerator, &count) &&
	count != 0)
	{
	attr_enumerator->destroy(attr_enumerator);
	attr_enumerator = this->db->query(this->db,
	"SELECT type, value FROM attributes "
	"WHERE pool = ? AND identity = 0",
	DB_UINT, attr_pool, DB_INT, DB_BLOB);
	break;
	}
	DESTROY_IF(attr_enumerator);
	attr_enumerator = NULL;
	}
	pool_enumerator->destroy(pool_enumerator);
	}

	/* lastly try to find global attributes */
	if (!attr_enumerator)
	{
	attr_enumerator = this->db->query(this->db,
	"SELECT type, value FROM attributes "
	"WHERE pool = 0 AND identity = 0",
	DB_INT, DB_BLOB);
	}
	}

	return (attr_enumerator ? attr_enumerator : enumerator_create_empty());
	}

	METHOD(attr_sql_provider_t, destroy, void,
	private_attr_sql_provider_t *this)
	{
	free(this);
	}

	/*
	* see header file
	*/
	attr_sql_provider_t attr_sql_provider_create(database_t db)
	{
	private_attr_sql_provider_t *this;

	INIT(this,
	.public = {
	.provider = {
	.acquire_address = _acquire_address,
	.release_address = _release_address,
	.create_attribute_enumerator = _create_attribute_enumerator,
	},
	.destroy = _destroy,
	},
	.db = db,
	.history = lib->settings->get_bool(lib->settings,
	"%s.plugins.attr-sql.lease_history", TRUE, lib->ns),
	);

	if (lib->settings->get_bool(lib->settings,
	"%s.plugins.attr-sql.crash_recovery", TRUE, lib->ns))
	{
	time_t now = time(NULL);

	/* close any "online" leases in the case we crashed */
	if (this->history)
	{
	this->db->execute(this->db, NULL,
	"INSERT INTO leases (address, identity, acquired, released)"
	" SELECT id, identity, acquired, ? FROM addresses "
	" WHERE released = 0", DB_UINT, now);
	}
	this->db->execute(this->db, NULL,
	"UPDATE addresses SET released = ? WHERE released = 0",
	DB_UINT, now);
	}
	return &this->public;
	}