gnutls_handshake(3) gnutls gnutls_handshake(3)
NAME
gnutls_handshake - API function
SYNOPSIS
#include <gnutls/gnutls.h>
gnutls_handshake(3) session);
ARGUMENTS
gnutls_session_t session
is a gnutls_session_t type.
DESCRIPTION
This function performs the handshake of the TLS/SSL protocol, and ini-
tializes the TLS session parameters.
The non-fatal errors expected by this function are: GNUTLS_E_INTER-
RUPTED, 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 (resump-
tion). For abbreviated handshakes, in client side, the gnutls_ses-
sion_set_data() should be called prior to this function to set parame-
ters 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: http://www.gnutls.org
COPYRIGHT
Copyright (C) 2001-2018 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
http://www.gnutls.org/manual/
gnutls 3.6.5 gnutls_handshake(3)
gnutls 3.6.5 - Generated Mon Jan 21 10:46:51 CST 2019