/*
 *  Copyright (C) 2004-2009 Christos Tsantilas
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 *  MA  02110-1301  USA.
 */

#ifndef __ACL_H
#define __ACL_H

#include "c-icap.h"
#include "net_io.h"
#include "types_ops.h"

#ifdef __cplusplus
extern "C"
{
#endif

/**
 \defgroup ACL Access lists API
 \ingroup API
 * Access control lists related API. Structures, functions and macros used
 * to define custom acl types, and use access control lists in services
 * and modules.
 */

#define MAX_NAME_LEN 31

/*ACL type structures and functions */
struct ci_request;
/**
 \ingroup ACL
 * This is the struct used to implement an acl type object.
 */
typedef struct ci_acl_type {

    /**
       \brief The acl type name
     */
    char name[MAX_NAME_LEN+1];

    /**
     \brief Pointer to the functions which retrieves the test data for
     *      this acl type
     *
     * This method extract the test data from request object for this acl
     * object. For example for the "src" acl type this function will extract
     * the icap client ip address
     \param req Pointer to the related ci_request_t object
     \param param Some acl types supports one parameter passed by the c-icap
     *            administrator
     \return A pointer to the test data
    */
    void *(*get_test_data)(struct ci_request *req, char *param);

    /**
     \brief Pointer to the function which release the acl test data
     *      (if required)
     *
     * This method releases the acl test data,which  allocated using the
     * get_test_data method
     \param req Pointer to the related ci_request_t object
     \param data Pointer to allocated test data
     */
    void (*free_test_data)(struct ci_request *req, void *data);

    /**
     \brief Pointer to the ci_types_ops_t struct which implements basic
     *      operations for the acl test data
     */
    const ci_type_ops_t *type;
} ci_acl_type_t;

struct ci_acl_type_list {
    ci_acl_type_t *acl_type_list;
    int acl_type_list_size;
    int acl_type_list_num;
};

int ci_acl_typelist_init(struct ci_acl_type_list *list);
int ci_acl_typelist_add(struct ci_acl_type_list *list, const ci_acl_type_t *type);
int ci_acl_typelist_release(struct ci_acl_type_list *list);
int ci_acl_typelist_reset(struct ci_acl_type_list *list);
const ci_acl_type_t *ci_acl_typelist_search(struct ci_acl_type_list *list, const char *name);


/*ACL specs structures and functions */

typedef struct ci_acl_data ci_acl_data_t;
struct ci_acl_data {
    void *data;
    ci_acl_data_t *next;
};

/**
   \brief This struct holds an access control list (acl).
   \ingroup ACL
   *
   * Imagine the following access control list defined in the c-icap config
   * file:\n
   * \code acl LOCALNET 127.0.0.1/255.255.255.255 192.168.1.0/255.255.255.0
   * \endcode
   * This struct represents access control lists like the above
 */
typedef struct ci_acl_spec ci_acl_spec_t;
struct ci_acl_spec {
    char name[MAX_NAME_LEN + 1];
    const ci_acl_type_t *type;
    char *parameter;
    ci_acl_data_t *data;
    ci_acl_spec_t *next;
};

/*Specs lists and access entries structures and functions */
typedef struct ci_specs_list ci_specs_list_t;
struct ci_specs_list {
    const ci_acl_spec_t *spec;
    int negate;
    ci_specs_list_t *next;
};

/**
 \brief An access entry object holds an access control list, and can be
 *      connected to linked lists of access entries.
 \ingroup ACL
 *
 * This struct used to implement lists of access control lists.
 * Each access entry can hold an "allow" or "deny" access control list.
 * An access entries list represents the following c-icap config lines:
 * \code
 *  icap_access allow LOCALNET LOCALHOST
 *  icap_access deny ALL
 * \endcode
 * each of the above lines represented by an ci_access_entry object.
 * The ci_access_entry objects can be connected to a simple linked list.
 *
 */
typedef struct ci_access_entry ci_access_entry_t;
struct ci_access_entry {
    int type;   /*CI_ACCESS_DENY or CI_ACCESS_ALLOW*/
    ci_specs_list_t *spec_list;
    ci_access_entry_t *next;
};

/**
 \brief Append a new access entry object to an access entries list
 \ingroup ACL
 *
 \param list Pointer to the access entry list
 \param type CI_ACCESS_ALLOW if CI_ACCESS_DENY to specify if this access entry holds an "allow" or "deny" access control list
 \return A pointer to the newly created access entry object
 */
CI_DECLARE_FUNC(ci_access_entry_t *) ci_access_entry_new(ci_access_entry_t **list, int type);

/**
 \brief Destroy an access entries list
 \ingroup ACL
 *
 \param list Pointer to the access entries list
*/
CI_DECLARE_FUNC(void) ci_access_entry_release(ci_access_entry_t *list);

CI_DECLARE_FUNC(const ci_acl_spec_t *) ci_access_entry_add_acl(ci_access_entry_t *access_entry, const ci_acl_spec_t *acl, int negate);

/**
 \brief Add an acl to an access entry object
 \ingroup ACL
 *
 \param access_entry Pointer to the access entry  object
 \param aclname The name of the acl to be added.
 \return non zero on success, zero otherwise
 */
CI_DECLARE_FUNC(int) ci_access_entry_add_acl_by_name(ci_access_entry_t *access_entry, const char *aclname);

/**
 \brief Check if an access entries list matches a request object
 \ingroup ACL
 *
 \param access_entry Pointer to the access entries list (a linked list of
 *                   ci_access_entry_t objects)
 \param req pointer to the request object (ci_request_t object)
 \return CI_ACCESS_ALLOW if request matches the access list, CI_ACCESS_DENY
 *       otherwise
 */
CI_DECLARE_FUNC(int) ci_access_entry_match_request(ci_access_entry_t *access_entry, ci_request_t *req);


/*Inititalizing, reseting and tools acl library functions */

/**
 \brief Initializes the c-icap acl subsystem. It is not thread safe
 \ingroup ACL
 */
CI_DECLARE_FUNC(void) ci_acl_init();

/**
 \brief Resets the c-icap acl subsystem. It is not thread safe
 \ingroup ACL
 */
CI_DECLARE_FUNC(void) ci_acl_reset();

CI_DECLARE_FUNC(const ci_acl_spec_t *) ci_acl_search(const char *name);
CI_DECLARE_FUNC(int) ci_acl_add_data(const char *name, const char *type, const char *data);

/**
 \brief Search for an acl type
 \ingroup ACL
 *
 \param name The name of the acl type
 \return Pointer to the ci_acl_type_t structure which implements the acl type,
 *       or NULL
 */
CI_DECLARE_FUNC(const ci_acl_type_t *) ci_acl_type_search(const char *name);

/**
 \brief Add a custom acl type to the c-icap acl subsystem
 \ingroup ACL
 *
 \param type Pointer to the c-acl_type_t struct which implements the acl type
 \return non zero on success, zero otherwise
 */
CI_DECLARE_FUNC(int) ci_acl_type_add(const ci_acl_type_t *type);

#ifdef __cplusplus
}
#endif

#endif/* __ACL_H*/
