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_AKA = 23,
  64 };
  65
  66 /**
  67  * enum names for eap_type_t.
  68  *
  69  * @ingroup eap
  70  */
  71 extern enum_name_t *eap_type_names;
  72
  73 /**
  74  * EAP code, type of an EAP message
  75  *
  76  * @ingroup eap
  77  */
  78 enum eap_code_t {
  79         EAP_REQUEST = 1,
  80         EAP_RESPONSE = 2,
  81         EAP_SUCCESS = 3,
  82         EAP_FAILURE = 4,
  83 };
  84
  85 /**
  86  * enum names for eap_code_t.
  87  *
  88  * @ingroup eap
  89  */
  90 extern enum_name_t *eap_code_names;
  91
  92
  93 /**
  94  * @brief Interface of an EAP method for server and client side.
  95  *
  96  * An EAP method initiates an EAP exchange and processes requests and
  97  * responses. An EAP method may need multiple exchanges before succeeding, and
  98  * the eap_authentication may use multiple EAP methods to authenticate a peer.
  99  * To accomplish these requirements, all EAP methods have their own
 100  * implementation while the eap_authenticatior uses one or more of these
 101  * EAP methods. Sending of EAP(SUCCESS/FAILURE) message is not the job
 102  * of the method, the eap_authenticator does this.
 103  * An EAP method may establish a MSK, this is used the complete the
 104  * authentication. Even if a mutual EAP method is used, the traditional
 105  * AUTH payloads are required. Only these include the nonces and messages from
 106  * ike_sa_init and therefore prevent man in the middle attacks.
 107  *
 108  * @b Constructors:
 109  *  - eap_method_create()
 110  *
 111  * @ingroup eap
 112  */
 113 struct eap_method_t {
 114
 115         /**
 116          * @brief Initiate the EAP exchange.
 117          *
 118          * initiate() is only useable for server implementations, as clients only
 119          * reply to server requests.
 120          * A eap_payload is created in "out" if result is NEED_MORE.
 121          *
 122          * @param this          calling object
 123          * @param out           eap_payload to send to the client
 124          * @return
 125          *                                      - NEED_MORE, if an other exchange is required
 126          *                                      - FAILED, if unable to create eap request payload
 127          */
 128         status_t (*initiate) (eap_method_t *this, eap_payload_t **out);
 129
 130         /**
 131          * @brief Process a received EAP message.
 132          *
 133          * A eap_payload is created in "out" if result is NEED_MORE.
 134          *
 135          * @param this          calling object
 136          * @param in            eap_payload response received
 137          * @param out           created eap_payload to send
 138          * @return
 139          *                                      - NEED_MORE, if an other exchange is required
 140          *                                      - FAILED, if EAP method failed
 141          *                                      - SUCCESS, if EAP method succeeded
 142          */
 143         status_t (*process) (eap_method_t *this, eap_payload_t *in,
 144                                                  eap_payload_t **out);
 145
 146         /**
 147          * @brief Get the EAP type implemented in this method.
 148          *
 149          * @param this          calling object
 150          * @return                      type of the EAP method
 151          */
 152         eap_type_t (*get_type) (eap_method_t *this);
 153
 154         /**
 155          * @brief Check if this EAP method authenticates the server.
 156          *
 157          * Some EAP methods provide mutual authentication and
 158          * allow authentication using only EAP, if the peer supports it.
 159          *
 160          * @param this          calling object
 161          * @return                      TRUE if methods provides mutual authentication
 162          */
 163         bool (*is_mutual) (eap_method_t *this);
 164
 165         /**
 166          * @brief Get the MSK established by this EAP method.
 167          *
 168          * Not all EAP methods establish a shared secret.
 169          *
 170          * @param this          calling object
 171          * @param msk           chunk receiving internal stored MSK
 172          * @return
 173          *                                      - SUCCESS, or
 174          *                                      - FAILED, if MSK not established (yet)
 175          */
 176         status_t (*get_msk) (eap_method_t *this, chunk_t *msk);
 177
 178         /**
 179          * @brief Destroys a eap_method_t object.
 180          *
 181          * @param this                          calling object
 182          */
 183         void (*destroy) (eap_method_t *this);
 184 };
 185
 186 /**
 187  * @brief Creates an EAP method for a specific type and role.
 188  *
 189  * @param eap_type              EAP type to use
 190  * @param role                  role of the eap_method, server or peer
 191  * @param server                ID of acting server
 192  * @param peer                  ID of involved peer (client)
 193  * @return                              eap_method_t object
 194  *
 195  * @ingroup eap
 196  */
 197 eap_method_t *eap_method_create(eap_type_t eap_type, eap_role_t role,
 198                                                                 identification_t *server, identification_t *peer);
 199
 200 /**
 201  * @brief (Re-)Load all EAP modules in the EAP modules directory.
 202  *
 203  * For security reasons, the directory and all it's modules must be owned
 204  * by root and must not be writeable by someone else.
 205  *
 206  * @param dir                   directory of the EAP modules
 207  *
 208  * @ingroup eap
 209  */
 210 void eap_method_load(char *directory);
 211
 212 /**
 213  * @brief Unload all loaded EAP modules
 214  *
 215  * @ingroup eap
 216  */
 217 void eap_method_unload();
 218
 219 /**
 220  * @brief Constructor definition for a pluggable EAP module.
 221  *
 222  * Each EAP module must define a constructor function which will return
 223  * an initialized object with the methods defined in eap_method_t. The
 224  * constructor must be named eap_create() and it's signature must be equal
 225  * to that of eap_constructor_t.
 226  * A module may implement only a single role. If it does not support the role
 227  * requested, NULL should be returned. Multiple modules are allowed of the
 228  * same EAP type to support seperate implementations of peer/server.
 229  *
 230  * @param role                  role the module will play, peer or server
 231  * @param server                ID of the server to use for credential lookup
 232  * @param peer                  ID of the peer to use for credential lookup
 233  * @return                              implementation of the eap_method_t interface
 234  *
 235  * @ingroup eap
 236  */
 237 typedef eap_method_t *(*eap_constructor_t)(eap_role_t role,
 238                                                                                    identification_t *server,
 239                                                                                    identification_t *peer);
 240
 241 #endif /* EAP_METHOD_H_ */