gnutls_handshake

gnutls_handshake(3)                  gnutls                  gnutls_handshake(3)



NAME
       gnutls_handshake - API function

SYNOPSIS
       #include <gnutls/gnutls.h>

       int gnutls_handshake(gnutls_session_t session);

ARGUMENTS
       gnutls_session_t session
                   is a gnutls_session_t type.

DESCRIPTION
       This function performs the handshake of the TLS/SSL protocol, and
       initializes the TLS session parameters.

       The non-fatal errors expected by this function are: GNUTLS_E_INTERRUPTED,
       GNUTLS_E_AGAIN, GNUTLS_E_WARNING_ALERT_RECEIVED. When this function is
       called for re-handshake under TLS 1.2 or earlier, the non-fatal error
       code GNUTLS_E_GOT_APPLICATION_DATA may also be returned.

       The former two interrupt the handshake procedure due to the transport
       layer being interrupted, and the latter because of a "warning" alert that
       was sent by the peer (it is always a good idea to check any received
       alerts). On these non-fatal errors call this function again, until it
       returns 0; cf.  gnutls_record_get_direction() and
       gnutls_error_is_fatal(). In DTLS sessions the non-fatal error
       GNUTLS_E_LARGE_PACKET is also possible, and indicates that the MTU should
       be adjusted.

       When this function is called by a server after a rehandshake request
       under TLS 1.2 or earlier the GNUTLS_E_GOT_APPLICATION_DATA error code
       indicates that some data were pending prior to peer initiating the
       handshake.  Under TLS 1.3 this function when called after a successful
       handshake, is a no-op and always succeeds in server side; in client side
       this function is equivalent to gnutls_session_key_update() with
       GNUTLS_KU_PEER flag.

       This function handles both full and abbreviated TLS handshakes
       (resumption).  For abbreviated handshakes, in client side, the
       gnutls_session_set_data() should be called prior to this function to set
       parameters from a previous session.  In server side, resumption is
       handled by either setting a DB back-end, or setting up keys for session
       tickets.

RETURNS
       GNUTLS_E_SUCCESS on a successful handshake, otherwise a negative error
       code.

REPORTING BUGS
       Report bugs to <bugs@gnutls.org>.
       Home page: https://www.gnutls.org


COPYRIGHT
       Copyright © 2001-2020 Free Software Foundation, Inc., and others.
       Copying and distribution of this file, with or without modification, are
       permitted in any medium without royalty provided the copyright notice and
       this notice are preserved.

SEE ALSO
       The full documentation for gnutls is maintained as a Texinfo manual.  If
       the /usr/share/doc/gnutls/ directory does not contain the HTML form visit

       https://www.gnutls.org/manual/

gnutls                               3.6.13                  gnutls_handshake(3)