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/*
* Copyright (C) 2006 Martin Willi
* 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.
*/
/**
* @defgroup eap_method eap_method
* @{ @ingroup eap
*/
#ifndef EAP_METHOD_H_
#define EAP_METHOD_H_
typedef struct eap_method_t eap_method_t;
typedef enum eap_role_t eap_role_t;
#include <library.h>
#include <plugins/plugin.h>
#include <utils/identification.h>
#include <eap/eap.h>
#include <encoding/payloads/eap_payload.h>
/**
* Role of an eap_method, SERVER or PEER (client)
*/
enum eap_role_t {
EAP_SERVER,
EAP_PEER,
};
/**
* enum names for eap_role_t.
*/
extern enum_name_t *eap_role_names;
/**
* Interface of an EAP method for server and client side.
*
* An EAP method initiates an EAP exchange and processes requests and
* responses. An EAP method may need multiple exchanges before succeeding, and
* the eap_authentication may use multiple EAP methods to authenticate a peer.
* To accomplish these requirements, all EAP methods have their own
* implementation while the eap_authenticatior uses one or more of these
* EAP methods. Sending of EAP(SUCCESS/FAILURE) message is not the job
* of the method, the eap_authenticator does this.
* An EAP method may establish a MSK, this is used the complete the
* authentication. Even if a mutual EAP method is used, the traditional
* AUTH payloads are required. Only these include the nonces and messages from
* ike_sa_init and therefore prevent man in the middle attacks.
* The EAP method must use an initial EAP identifier value != 0, as a preceding
* EAP-Identity exchange always uses identifier 0.
*/
struct eap_method_t {
/**
* Initiate the EAP exchange.
*
* initiate() is only useable for server implementations, as clients only
* reply to server requests.
* A eap_payload is created in "out" if result is NEED_MORE.
*
* @param out eap_payload to send to the client
* @return
* - NEED_MORE, if an other exchange is required
* - FAILED, if unable to create eap request payload
*/
status_t (*initiate) (eap_method_t *this, eap_payload_t **out);
/**
* Process a received EAP message.
*
* A eap_payload is created in "out" if result is NEED_MORE.
*
* @param in eap_payload response received
* @param out created eap_payload to send
* @return
* - NEED_MORE, if an other exchange is required
* - FAILED, if EAP method failed
* - SUCCESS, if EAP method succeeded
*/
status_t (*process) (eap_method_t *this, eap_payload_t *in,
eap_payload_t **out);
/**
* Get the EAP type implemented in this method.
*
* @param vendor pointer receiving vendor identifier for type, 0 for none
* @return type of the EAP method
*/
eap_type_t (*get_type) (eap_method_t *this, uint32_t *vendor);
/**
* Check if this EAP method authenticates the server.
*
* Some EAP methods provide mutual authentication and
* allow authentication using only EAP, if the peer supports it.
*
* @return TRUE if methods provides mutual authentication
*/
bool (*is_mutual) (eap_method_t *this);
/**
* Get the MSK established by this EAP method.
*
* Not all EAP methods establish a shared secret. For implementations of
* the EAP-Identity method, get_msk() returns the received identity.
*
* @param msk chunk receiving internal stored MSK
* @return
* - SUCCESS, or
* - FAILED, if MSK not established (yet)
*/
status_t (*get_msk) (eap_method_t *this, chunk_t *msk);
/**
* Get the current EAP identifier.
*
* @return current EAP identifier
*/
uint8_t (*get_identifier) (eap_method_t *this);
/**
* Set the EAP identifier to a deterministic value, overwriting
* the randomly initialized default value.
*
* @param identifier current EAP identifier
*/
void (*set_identifier) (eap_method_t *this, uint8_t identifier);
/**
* Get authentication details performed by this EAP method.
*
* After EAP completion, the auth data contains additional information
* of the authentication process, used certificates etc.
* This method is optional to implement, but if it is, it must return
* a valid auth_cfg.
*
* @return auth method, internal data
*/
auth_cfg_t* (*get_auth)(eap_method_t *this);
/**
* Destroys a eap_method_t object.
*/
void (*destroy) (eap_method_t *this);
};
/**
* Constructor definition for a pluggable EAP method.
*
* Each EAP module must define a constructor function which will return
* an initialized object with the methods defined in eap_method_t.
* Constructors for server and peers are identical, to support both roles
* of a EAP method, a plugin needs register two constructors in the
* eap_manager_t.
* The passed identites are of type ID_EAP and valid only during the
* constructor invocation.
*
* @param server ID of the server to use for credential lookup
* @param peer ID of the peer to use for credential lookup
* @return implementation of the eap_method_t interface
*/
typedef eap_method_t *(*eap_constructor_t)(identification_t *server,
identification_t *peer);
/**
* Helper function to (un-)register EAP methods from plugin features.
*
* This function is a plugin_feature_callback_t and can be used with the
* PLUGIN_CALLBACK macro to register a EAP method constructor.
*
* @param plugin plugin registering the EAP method constructor
* @param feature associated plugin feature
* @param reg TRUE to register, FALSE to unregister.
* @param data data passed to callback, an eap_constructor_t
*/
bool eap_method_register(plugin_t *plugin, plugin_feature_t *feature,
bool reg, void *data);
#endif /** EAP_METHOD_H_ @}*/
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