5 SSL_connect - initiate the TLS/SSL handshake with an TLS/SSL server
9 #include <openssl/ssl.h>
11 int SSL_connect(SSL *ssl);
15 SSL_connect() initiates the TLS/SSL handshake with a server. The communication
16 channel must already have been set and assigned to the B<ssl> by setting an
17 underlying B<BIO>. The behaviour of SSL_connect() depends on the underlying
20 If the underlying BIO is B<blocking>, SSL_connect() will only return once the
21 handshake has been finished or an error occurred.
23 If the underlying BIO is B<non-blocking>, SSL_connect() will also return
24 when the underlying BIO could not satisfy the needs of SSL_connect()
25 to continue the handshake. In this case a call to SSL_get_error() with the
26 return value of SSL_connect() will yield B<SSL_ERROR_WANT_READ> or
27 B<SSL_ERROR_WANT_WRITE>. The calling process then must repeat the call after
28 taking appropriate action to satisfy the needs of SSL_connect().
29 The action depends on the underlying BIO. When using a non-blocking socket,
30 nothing is to be done, but select() can be used to check for the required
31 condition. When using a buffering BIO, like a BIO pair, data must be written
32 into or retrieved out of the BIO before being able to continue.
36 The following return values can occur:
42 The TLS/SSL handshake was successfully completed, a TLS/SSL connection has been
47 The TLS/SSL handshake was not successful but was shut down controlled and
48 by the specifications of the TLS/SSL protocol. Call SSL_get_error() with the
49 return value B<ret> to find out the reason.
53 The TLS/SSL handshake was not successful, because a fatal error occurred either
54 at the protocol level or a connection failure occurred. The shutdown was
55 not clean. It can also occur of action is need to continue the operation
56 for non-blocking BIOs. Call SSL_get_error() with the return value B<ret>
57 to find out the reason.
63 L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_accept(3)|SSL_accept(3)>,
64 L<SSL_shutdown(3)|SSL_shutdown(3)>, L<ssl(3)|ssl(3)> , L<bio(3)|bio(3)>