df354edb4434f1da494bfa292918a50e36d54b75
[strongswan.git] / src / libcharon / sa / authenticators / eap / eap_method.h
1 /*
2 * Copyright (C) 2006 Martin Willi
3 * Hochschule fuer Technik Rapperswil
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
12 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * for more details.
14 */
15
16 /**
17 * @defgroup eap_method eap_method
18 * @{ @ingroup eap
19 */
20
21 #ifndef EAP_METHOD_H_
22 #define EAP_METHOD_H_
23
24 typedef struct eap_method_t eap_method_t;
25 typedef enum eap_role_t eap_role_t;
26 typedef enum eap_code_t eap_code_t;
27
28 #include <library.h>
29 #include <utils/identification.h>
30 #include <encoding/payloads/eap_payload.h>
31
32 /**
33 * Role of an eap_method, SERVER or PEER (client)
34 */
35 enum eap_role_t {
36 EAP_SERVER,
37 EAP_PEER,
38 };
39 /**
40 * enum names for eap_role_t.
41 */
42 extern enum_name_t *eap_role_names;
43
44 /**
45 * Lookup the EAP method type from a string.
46 *
47 * @param name EAP method name (such as "md5", "aka")
48 * @return method type, 0 if unkown
49 */
50 eap_type_t eap_type_from_string(char *name);
51
52 /**
53 * EAP code, type of an EAP message
54 */
55 enum eap_code_t {
56 EAP_REQUEST = 1,
57 EAP_RESPONSE = 2,
58 EAP_SUCCESS = 3,
59 EAP_FAILURE = 4,
60 };
61
62 /**
63 * enum names for eap_code_t.
64 */
65 extern enum_name_t *eap_code_names;
66
67 /**
68 * short string enum names for eap_code_t.
69 */
70 extern enum_name_t *eap_code_short_names;
71
72 /**
73 * Interface of an EAP method for server and client side.
74 *
75 * An EAP method initiates an EAP exchange and processes requests and
76 * responses. An EAP method may need multiple exchanges before succeeding, and
77 * the eap_authentication may use multiple EAP methods to authenticate a peer.
78 * To accomplish these requirements, all EAP methods have their own
79 * implementation while the eap_authenticatior uses one or more of these
80 * EAP methods. Sending of EAP(SUCCESS/FAILURE) message is not the job
81 * of the method, the eap_authenticator does this.
82 * An EAP method may establish a MSK, this is used the complete the
83 * authentication. Even if a mutual EAP method is used, the traditional
84 * AUTH payloads are required. Only these include the nonces and messages from
85 * ike_sa_init and therefore prevent man in the middle attacks.
86 * The EAP method must use an initial EAP identifier value != 0, as a preceding
87 * EAP-Identity exchange always uses identifier 0.
88 */
89 struct eap_method_t {
90
91 /**
92 * Initiate the EAP exchange.
93 *
94 * initiate() is only useable for server implementations, as clients only
95 * reply to server requests.
96 * A eap_payload is created in "out" if result is NEED_MORE.
97 *
98 * @param out eap_payload to send to the client
99 * @return
100 * - NEED_MORE, if an other exchange is required
101 * - FAILED, if unable to create eap request payload
102 */
103 status_t (*initiate) (eap_method_t *this, eap_payload_t **out);
104
105 /**
106 * Process a received EAP message.
107 *
108 * A eap_payload is created in "out" if result is NEED_MORE.
109 *
110 * @param in eap_payload response received
111 * @param out created eap_payload to send
112 * @return
113 * - NEED_MORE, if an other exchange is required
114 * - FAILED, if EAP method failed
115 * - SUCCESS, if EAP method succeeded
116 */
117 status_t (*process) (eap_method_t *this, eap_payload_t *in,
118 eap_payload_t **out);
119
120 /**
121 * Get the EAP type implemented in this method.
122 *
123 * @param vendor pointer receiving vendor identifier for type, 0 for none
124 * @return type of the EAP method
125 */
126 eap_type_t (*get_type) (eap_method_t *this, u_int32_t *vendor);
127
128 /**
129 * Check if this EAP method authenticates the server.
130 *
131 * Some EAP methods provide mutual authentication and
132 * allow authentication using only EAP, if the peer supports it.
133 *
134 * @return TRUE if methods provides mutual authentication
135 */
136 bool (*is_mutual) (eap_method_t *this);
137
138 /**
139 * Get the MSK established by this EAP method.
140 *
141 * Not all EAP methods establish a shared secret. For implementations of
142 * the EAP-Identity method, get_msk() returns the received identity.
143 *
144 * @param msk chunk receiving internal stored MSK
145 * @return
146 * - SUCCESS, or
147 * - FAILED, if MSK not established (yet)
148 */
149 status_t (*get_msk) (eap_method_t *this, chunk_t *msk);
150
151 /**
152 * Destroys a eap_method_t object.
153 */
154 void (*destroy) (eap_method_t *this);
155 };
156
157 /**
158 * Constructor definition for a pluggable EAP method.
159 *
160 * Each EAP module must define a constructor function which will return
161 * an initialized object with the methods defined in eap_method_t.
162 * Constructors for server and peers are identical, to support both roles
163 * of a EAP method, a plugin needs register two constructors in the
164 * eap_manager_t.
165 * The passed identites are of type ID_EAP and valid only during the
166 * constructor invocation.
167 *
168 * @param server ID of the server to use for credential lookup
169 * @param peer ID of the peer to use for credential lookup
170 * @return implementation of the eap_method_t interface
171 */
172 typedef eap_method_t *(*eap_constructor_t)(identification_t *server,
173 identification_t *peer);
174
175 #endif /** EAP_METHOD_H_ @}*/