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gnutls_session_get_data2(3) gnutls gnutls_session_get_data2(3)
gnutls_session_get_data2 - API function
int gnutls_session_get_data2(gnutls_session_t session, gnutls_datum_t *
is a gnutls_session_t type.
gnutls_datum_t * data
is a pointer to a datum that will hold the session.
Returns necessary parameters to support resumption. The client should
call this function and store the returned session data. A session can
be resumed later by calling gnutls_session_set_data() with the returned
data. Note that under TLS 1.3, it is recommended for clients to use
session parameters only once, to prevent passive-observers from
correlating the different connections.
The returned data are allocated and must be released using
This function will fail if called prior to handshake completion. In
case of false start TLS, the handshake completes only after data have
been successfully received from the peer.
Under TLS1.3 session resumption is possible only after a session ticket
is received by the client. To ensure that such a ticket has been
received use gnutls_session_get_flags() and check for flag
GNUTLS_SFLAGS_SESSION_TICKET; if this flag is not set, this function
will wait for a new ticket within an estimated roundtrip, and if not
received will return dummy data which cannot lead to resumption.
To get notified when new tickets are received by the server use
gnutls_handshake_set_hook_function() to wait for
GNUTLS_HANDSHAKE_NEW_SESSION_TICKET messages. Each call of
gnutls_session_get_data2() after a ticket is received, will return
session resumption data corresponding to the last received ticket.
Note that this function under TLS1.3 requires a callback to be set with
gnutls_transport_set_pull_timeout_function() for successful operation.
There was a bug before 3.6.10 which could make this function fail if
that callback was not set. On later versions if not set, the function
will return a successful error code, but will return dummy data that
cannot lead to a resumption.
On success, GNUTLS_E_SUCCESS (0) is returned, otherwise an error code
Report bugs to <firstname.lastname@example.org>.
Home page: https://www.gnutls.org
Copyright (C) 2001- 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.
The full documentation for gnutls is maintained as a Texinfo manual.
If the /usr/local/share/doc/gnutls/ directory does not contain the HTML
gnutls 3.7.8 gnutls_session_get_data2(3)