NAME    [Toc]    [Back]

       SSL_do_handshake - perform a TLS/SSL handshake

SYNOPSIS    [Toc]    [Back]

        #include <openssl/ssl.h>

        int SSL_do_handshake(SSL *ssl);

DESCRIPTION    [Toc]    [Back]

       SSL_do_handshake() will wait for a SSL/TLS handshake to
       take place. If the connection is in client mode, the handshake
 will be started. The handshake routines may have to
       be explicitly set in advance using either
       SSL_set_connect_state(3) or SSL_set_accept_state(3).

NOTES    [Toc]    [Back]

       The behaviour of SSL_do_handshake() depends on the underlying
 BIO.

       If the underlying BIO is blocking, SSL_do_handshake() will
       only return once the handshake has been finished or an
       error occurred, except for SGC (Server Gated Cryptography).
 For SGC, SSL_do_handshake() may return with -1, but
       SSL_get_error() will yield SSL_ERROR_WANT_READ/WRITE and
       SSL_do_handshake() should be called again.

       If the underlying BIO is non-blocking, SSL_do_handshake()
       will also return when the underlying BIO could not satisfy
       the needs of SSL_do_handshake() to continue the handshake.
       In this case a call to SSL_get_error() with the return
       value of SSL_do_handshake() 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_do_handshake().  The action depends on
       the underlying BIO. When using a non-blocking socket,
       nothing is to be done, but select() 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    [Toc]    [Back]

       The following return values can occur:

       1   The TLS/SSL handshake was successfully completed, a
           TLS/SSL connection has been established.

       0   The TLS/SSL handshake was not successful but was shut
           down controlled and by the specifications of the
           TLS/SSL protocol. Call SSL_get_error() with the return
           value ret to find out the reason.

       <0  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 of action is need to continue
           the operation for non-blocking BIOs. Call
           SSL_get_error() with the return value ret to find out
           the reason.

SEE ALSO    [Toc]    [Back]

       SSL_get_error(3), SSL_connect(3), SSL_accept(3), ssl(3),
       bio(3), SSL_set_connect_state(3)


OpenBSD 3.6                 2002-09-05                          2