gnutls_session_get_data2(3)          gnutls          gnutls_session_get_data2(3)

       gnutls_session_get_data2 - API function

       #include <gnutls/gnutls.h>

       int gnutls_session_get_data2(gnutls_session_t session, gnutls_datum_t *

       gnutls_session_t session
                   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 rountrip, 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 is

       Report bugs to <>.
       Home page:

       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.

       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

gnutls                               3.6.13          gnutls_session_get_data2(3)