src/charon/sa/authenticators/eap/eap_method.h

   1 /**
   2  * @file eap_method.h
   3  *
   4  * @brief Interface eap_method_t.
   5  *
   6  */
   7
   8 /*
   9  * Copyright (C) 2006 Martin Willi
  10  * Hochschule fuer Technik Rapperswil
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU General Public License as published by the
  14  * Free Software Foundation; either version 2 of the License, or (at your
  15  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  20  * for more details.
  21  */
  22
  23 #ifndef EAP_METHOD_H_
  24 #define EAP_METHOD_H_
  25
  26 typedef struct eap_method_t eap_method_t;
  27 typedef enum eap_role_t eap_role_t;
  28 typedef enum eap_type_t eap_type_t;
  29 typedef enum eap_code_t eap_code_t;
  30
  31 #include <library.h>
  32 #include <utils/identification.h>
  33 #include <encoding/payloads/eap_payload.h>
  34
  35 /**
  36  * Role of an eap_method, SERVER or PEER (client)
  37  *
  38  * @ingroup eap
  39  */
  40 enum eap_role_t {
  41         EAP_SERVER,
  42         EAP_PEER,
  43 };
  44 /**
  45  * enum names for eap_role_t.
  46  *
  47  * @ingroup eap
  48  */
  49 extern enum_name_t *eap_role_names;
  50
  51 /**
  52  * EAP types, defines the EAP method implementation
  53  *
  54  * @ingroup eap
  55  */
  56 enum eap_type_t {
  57         EAP_IDENTITY = 1,
  58         EAP_NOTIFICATION = 2,
  59         EAP_NAK = 3,
  60         EAP_MD5 = 4,
  61         EAP_ONE_TIME_PASSWORD = 5,
  62         EAP_TOKEN_CARD = 6,
  63         EAP_SIM = 18,
  64         EAP_AKA = 23,
  65 };
  66
  67 /**
  68  * enum names for eap_type_t.
  69  *
  70  * @ingroup eap
  71  */
  72 extern enum_name_t *eap_type_names;
  73
  74 /**
  75  * EAP code, type of an EAP message
  76  *
  77  * @ingroup eap
  78  */
  79 enum eap_code_t {
  80         EAP_REQUEST = 1,
  81         EAP_RESPONSE = 2,
  82         EAP_SUCCESS = 3,
  83         EAP_FAILURE = 4,
  84 };
  85
  86 /**
  87  * enum names for eap_code_t.
  88  *
  89  * @ingroup eap
  90  */
  91 extern enum_name_t *eap_code_names;
  92
  93
  94 /**
  95  * @brief Interface of an EAP method for server and client side.
  96  *
  97  * An EAP method initiates an EAP exchange and processes requests and
  98  * responses. An EAP method may need multiple exchanges before succeeding, and
  99  * the eap_authentication may use multiple EAP methods to authenticate a peer.
 100  * To accomplish these requirements, all EAP methods have their own
 101  * implementation while the eap_authenticatior uses one or more of these
 102  * EAP methods. Sending of EAP(SUCCESS/FAILURE) message is not the job
 103  * of the method, the eap_authenticator does this.
 104  * An EAP method may establish a MSK, this is used the complete the
 105  * authentication. Even if a mutual EAP method is used, the traditional
 106  * AUTH payloads are required. Only these include the nonces and messages from
 107  * ike_sa_init and therefore prevent man in the middle attacks.
 108  *
 109  * @b Constructors:
 110  *  - eap_method_create()
 111  *
 112  * @ingroup eap
 113  */
 114 struct eap_method_t {
 115
 116         /**
 117          * @brief Initiate the EAP exchange.
 118          *
 119          * initiate() is only useable for server implementations, as clients only
 120          * reply to server requests.
 121          * A eap_payload is created in "out" if result is NEED_MORE.
 122          *
 123          * @param this          calling object
 124          * @param out           eap_payload to send to the client
 125          * @return
 126          *                                      - NEED_MORE, if an other exchange is required
 127          *                                      - FAILED, if unable to create eap request payload
 128          */
 129         status_t (*initiate) (eap_method_t *this, eap_payload_t **out);
 130
 131         /**
 132          * @brief Process a received EAP message.
 133          *
 134          * A eap_payload is created in "out" if result is NEED_MORE.
 135          *
 136          * @param this          calling object
 137          * @param in            eap_payload response received
 138          * @param out           created eap_payload to send
 139          * @return
 140          *                                      - NEED_MORE, if an other exchange is required
 141          *                                      - FAILED, if EAP method failed
 142          *                                      - SUCCESS, if EAP method succeeded
 143          */
 144         status_t (*process) (eap_method_t *this, eap_payload_t *in,
 145                                                  eap_payload_t **out);
 146
 147         /**
 148          * @brief Get the EAP type implemented in this method.
 149          *
 150          * @param this          calling object
 151          * @return                      type of the EAP method
 152          */
 153         eap_type_t (*get_type) (eap_method_t *this);
 154
 155         /**
 156          * @brief Check if this EAP method authenticates the server.
 157          *
 158          * Some EAP methods provide mutual authentication and
 159          * allow authentication using only EAP, if the peer supports it.
 160          *
 161          * @param this          calling object
 162          * @return                      TRUE if methods provides mutual authentication
 163          */
 164         bool (*is_mutual) (eap_method_t *this);
 165
 166         /**
 167          * @brief Get the MSK established by this EAP method.
 168          *
 169          * Not all EAP methods establish a shared secret.
 170          *
 171          * @param this          calling object
 172          * @param msk           chunk receiving internal stored MSK
 173          * @return
 174          *                                      - SUCCESS, or
 175          *                                      - FAILED, if MSK not established (yet)
 176          */
 177         status_t (*get_msk) (eap_method_t *this, chunk_t *msk);
 178
 179         /**
 180          * @brief Destroys a eap_method_t object.
 181          *
 182          * @param this                          calling object
 183          */
 184         void (*destroy) (eap_method_t *this);
 185 };
 186
 187 /**
 188  * @brief Creates an EAP method for a specific type and role.
 189  *
 190  * @param eap_type              EAP type to use
 191  * @param role                  role of the eap_method, server or peer
 192  * @param server                ID of acting server
 193  * @param peer                  ID of involved peer (client)
 194  * @return                              eap_method_t object
 195  *
 196  * @ingroup eap
 197  */
 198 eap_method_t *eap_method_create(eap_type_t eap_type, eap_role_t role,
 199                                                                 identification_t *server, identification_t *peer);
 200
 201 /**
 202  * @brief (Re-)Load all EAP modules in the EAP modules directory.
 203  *
 204  * For security reasons, the directory and all it's modules must be owned
 205  * by root and must not be writeable by someone else.
 206  *
 207  * @param dir                   directory of the EAP modules
 208  *
 209  * @ingroup eap
 210  */
 211 void eap_method_load(char *directory);
 212
 213 /**
 214  * @brief Unload all loaded EAP modules
 215  *
 216  * @ingroup eap
 217  */
 218 void eap_method_unload();
 219
 220 /**
 221  * @brief Constructor definition for a pluggable EAP module.
 222  *
 223  * Each EAP module must define a constructor function which will return
 224  * an initialized object with the methods defined in eap_method_t. The
 225  * constructor must be named eap_create() and it's signature must be equal
 226  * to that of eap_constructor_t.
 227  * A module may implement only a single role. If it does not support the role
 228  * requested, NULL should be returned. Multiple modules are allowed of the
 229  * same EAP type to support seperate implementations of peer/server.
 230  *
 231  * @param role                  role the module will play, peer or server
 232  * @param server                ID of the server to use for credential lookup
 233  * @param peer                  ID of the peer to use for credential lookup
 234  * @return                              implementation of the eap_method_t interface
 235  *
 236  * @ingroup eap
 237  */
 238 typedef eap_method_t *(*eap_constructor_t)(eap_role_t role,
 239                                                                                    identification_t *server,
 240                                                                                    identification_t *peer);
 241
 242 #endif /* EAP_METHOD_H_ */