NAME

       gnutls_session_get_data2 - API function

SYNOPSIS

       #include <gnutls/gnutls.h>

       int gnutls_session_get_data2(gnutls_session_t session, gnutls_datum_t * data);

ARGUMENTS

       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.

DESCRIPTION

       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 gnutls_free().

       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.

RETURNS

       On success, GNUTLS_E_SUCCESS (0) is returned, otherwise an error code is returned.

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/

gnutls                                                3.8.3                          gnutls_session_get_data2(3)