5 SSL_CTX_new, SSLv3_method, SSLv3_server_method, SSLv3_client_method,
6 TLSv1_method, TLSv1_server_method, TLSv1_client_method, TLSv1_1_method,
7 TLSv1_1_server_method, TLSv1_1_client_method, TLS_method,
8 TLS_server_method, TLS_client_method, SSLv23_method, SSLv23_server_method,
9 SSLv23_client_method, DTLS_method, DTLS_server_method, DTLS_client_method,
10 DTLSv1_method, DTLSv1_server_method, DTLSv1_client_method,
11 DTLSv1_2_method, DTLSv1_2_server_method, DTLSv1_2_client_method -
12 create a new SSL_CTX object as framework for TLS/SSL or DTLS enabled
17 #include <openssl/ssl.h>
19 SSL_CTX *SSL_CTX_new(const SSL_METHOD *method);
21 const SSL_METHOD *TLS_method(void);
22 const SSL_METHOD *TLS_server_method(void);
23 const SSL_METHOD *TLS_client_method(void);
25 #define SSLv23_method TLS_method
26 #define SSLv23_server_method TLS_server_method
27 #define SSLv23_client_method TLS_client_method
29 #ifndef OPENSSL_NO_SSL3_METHOD
30 const SSL_METHOD *SSLv3_method(void);
31 const SSL_METHOD *SSLv3_server_method(void);
32 const SSL_METHOD *SSLv3_client_method(void);
35 const SSL_METHOD *TLSv1_method(void);
36 const SSL_METHOD *TLSv1_server_method(void);
37 const SSL_METHOD *TLSv1_client_method(void);
39 const SSL_METHOD *TLSv1_1_method(void);
40 const SSL_METHOD *TLSv1_1_server_method(void);
41 const SSL_METHOD *TLSv1_1_client_method(void);
43 const SSL_METHOD *TLSv1_2_method(void);
44 const SSL_METHOD *TLSv1_2_server_method(void);
45 const SSL_METHOD *TLSv1_2_client_method(void);
47 const SSL_METHOD *DTLS_method(void);
48 const SSL_METHOD *DTLS_server_method(void);
49 const SSL_METHOD *DTLS_client_method(void);
51 const SSL_METHOD *DTLSv1_method(void);
52 const SSL_METHOD *DTLSv1_server_method(void);
53 const SSL_METHOD *DTLSv1_client_method(void);
55 const SSL_METHOD *DTLSv1_2_method(void);
56 const SSL_METHOD *DTLSv1_2_server_method(void);
57 const SSL_METHOD *DTLSv1_2_client_method(void);
61 SSL_CTX_new() creates a new B<SSL_CTX> object as framework to
62 establish TLS/SSL or DTLS enabled connections.
66 The SSL_CTX object uses B<method> as connection method.
67 The methods exist in a generic type (for client and server use), a server only
68 type, and a client only type.
69 B<method> can be of the following types:
73 =item SSLv3_method(), SSLv3_server_method(), SSLv3_client_method()
75 An SSL connection established with these methods will only understand
77 A client will send out a SSLv3 client hello messages and will
78 indicate that it supports SSLv3.
79 A server will only understand SSLv3 client hello message and only
80 support the SSLv3 protocol.
82 =item TLSv1_method(), TLSv1_server_method(), TLSv1_client_method()
84 A TLS connection established with these methods will only understand
87 =item TLSv1_1_method(), TLSv1_1_server_method(), TLSv1_1_client_method()
89 A TLS connection established with these methods will only understand
92 =item TLSv1_2_method(), TLSv1_2_server_method(), TLSv1_2_client_method()
94 A TLS connection established with these methods will only understand
97 =item TLS_method(), TLS_server_method(), TLS_client_method()
99 A TLS/SSL connection established with these methods may understand
100 the SSLv3, TLSv1, TLSv1.1 and TLSv1.2 protocols.
102 If extensions are required (for example server name)
103 a client will send out TLSv1 client hello messages including extensions and
104 will indicate that it also understands TLSv1.1, TLSv1.2 and permits a
105 fallback to SSLv3. A server will support SSLv3, TLSv1, TLSv1.1 and TLSv1.2
106 protocols. This is the best choice when compatibility is a concern.
108 =item SSLv23_method(), SSLv23_server_method(), SSLv23_client_method()
110 Use of these functions is deprecated. They have been replaced with TLS_method(),
111 TLS_server_method() and TLS_client_method() respectively. New code should use
112 those functions instead.
114 =item DTLS_method(), DTLS_server_method(), DTLS_client_method()
116 A DTLS connection established with those methods understands all
117 supported DTLS protocols.
118 Currently supported protocols are DTLS 1.0 and DTLS 1.2.
120 =item DTLSv1_method(), DTLSv1_server_method(), DTLSv1_client_method()
122 A DTLS connection established with these methods will only understand
123 the DTLS 1.0 protocol.
125 =item DTLSv1_2_method(), DTLSv1_2_server_method(), DTLSv1_2_client_method()
127 A DTLS connection established with these methods will only understand
128 the DTLS 1.2 protocol.
132 TLS_method(), TLS_server_method(), TLS_client_method(), DTLS_method(),
133 DTLS_server_method() and DTLS_client_method() are the version
135 All other methods only support one specific protocol version.
136 Use these methods instead of the other version specific methods.
138 If you want to limit the supported protocols for the version flexible
139 methods you can use SSL_CTX_set_min_proto_version(),
140 SSL_set_min_proto_version(), SSL_CTX_set_max_proto_version() and
141 SSL_set_max_proto_version() functions.
142 They can also be limited using by using an option like SSL_OP_NO_SSLv3
143 of the SSL_CTX_set_options() or SSL_set_options() functions, but
144 that's not recommended.
145 Using these functions it is possible to choose e.g. TLS_server_method()
146 and be able to negotiate with all possible clients, but to only
147 allow newer protocols like TLS 1.0, TLS 1.1 or TLS 1.2.
149 SSL_CTX_new() initializes the list of ciphers, the session cache
150 setting, the callbacks, the keys and certificates and the options
151 to its default values.
155 The following return values can occur:
161 The creation of a new SSL_CTX object failed. Check the error stack to
164 =item Pointer to an SSL_CTX object
166 The return value points to an allocated SSL_CTX object.
172 Support for SSLv2 and the corresponding SSLv2_method(),
173 SSLv2_server_method() and SSLv2_client_method() functions where
174 removed in OpenSSL 1.1.0.
176 SSLv23_method(), SSLv23_server_method() and SSLv23_client_method()
177 were deprecated and the preferred TLS_method(), TLS_server_method()
178 and TLS_client_method() functions were introduced in OpenSSL 1.1.0.
182 L<SSL_CTX_free(3)>, L<SSL_accept(3)>,
183 L<SSL_CTX_set_min_proto_version(3)>,
184 L<ssl(3)>, L<SSL_set_connect_state(3)>