gnutls_handshake(3) — Linux manual page
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 © 2001-2023 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/
COLOPHON
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manual page, send it to bugs@gnutls.org. This page was obtained
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