SSL_connect(3)SSL_connect(3)NAMESSL_connect - Initiate the TLS/SSL handshake with an TLS/SSL server
SYNOPSIS
#include <openssl/ssl.h>
int SSL_connect(
SSL *ssl );
DESCRIPTION
The SSL_connect() function initiates the TLS/SSL handshake with a
server. The communication channel must already have been set and
assigned to the ssl by setting an underlying BIO.
NOTES
The behavior of the SSL_connect() function depends on the underlying
BIO.
If the underlying BIO is blocking, the SSL_connect() function will only
return once the handshake has been finished or an error occurred.
If the underlying BIO is non-blocking, the SSL_connect() function will
also return when the underlying BIO could not satisfy the needs of
SSL_connect() to continue the handshake. In this case, a call to
SSL_get_error() with the return value of SSL_connect() will yield
SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE. The calling process then
must repeat the call after taking appropriate action to satisfy the
needs of SSL_connect(). The action depends on the underlying BIO. When
using a non-blocking socket, nothing is to be done, but the select()
function can be used to check for the required condition. When using a
buffering BIO, like a BIO pair, data must be written into or retrieved
out of the BIO before being able to continue.
RETURN VALUES
The following return values can occur: The TLS/SSL handshake was suc‐
cessfully completed. A TLS/SSL connection was established. The
TLS/SSL handshake was not successful but was shut down controlled and
by the specifications of the TLS/SSL protocol. Call the
SSL_get_error() function with the return value ret to find out the rea‐
son. The TLS/SSL handshake was not successful, because a fatal error
occurred either at the protocol level or a connection failure occurred.
The shutdown was not clean. It can also occur if action is needed to
continue the operation for non-blocking BIOs. Call the SSL_get_error()
function with the return value ret to find out the reason.
SEE ALSO
Functions: SSL_get_error(3), SSL_accept(3), SSL_shutdown(3), ssl(3),
bio(3), SSL_set_connect_state(3), SSL_do_handshake(3), SSL_CTX_new(3)SSL_connect(3)