NAME

       gnutls_certificate_set_retrieve_function - API function

SYNOPSIS

       #include <gnutls/gnutls.h>

       void    gnutls_certificate_set_retrieve_function(gnutls_certificate_credentials_t    cred,
       gnutls_certificate_retrieve_function * func);

ARGUMENTS

       gnutls_certificate_credentials_t cred
                   is a gnutls_certificate_credentials_t type.

       gnutls_certificate_retrieve_function * func
                   is the callback function

DESCRIPTION

       This function sets a callback to be called in order to retrieve the certificate to be used
       in the handshake. The callback will take control only if a certificate is requested by the
       peer. You are advised to use  gnutls_certificate_set_retrieve_function2()  because  it  is
       much more efficient in the processing it requires from gnutls.

       The   callback's   function   prototype   is:   int   (*callback)(gnutls_session_t,  const
       gnutls_datum_t*  req_ca_dn,  int  nreqs,  const   gnutls_pk_algorithm_t*   pk_algos,   int
       pk_algos_length, gnutls_retr2_st* st);

        req_ca_dn is only used in X.509 certificates.  Contains a list with the CA names that the
       server considers trusted.  This  is  a  hint  and  typically  the  client  should  send  a
       certificate  that  is  signed  by  one  of these CAs. These names, when available, are DER
       encoded. To get a more meaningful value use the function gnutls_x509_rdn_get().

        pk_algos contains a list with server's acceptable signature algorithms.  The  certificate
       returned should support the server's given algorithms.

        st should contain the certificates and private keys.

       If the callback function is provided then gnutls will call it, in the handshake, after the
       certificate request message has been received.

       In server side pk_algos and req_ca_dn are NULL.

       The callback function should set the certificate list to be sent, and return 0 on success.
       If  no certificate was selected then the number of certificates should be set to zero. The
       value (-1) indicates error and the handshake will be terminated. If both certificates  are
       set in the credentials and a callback is available, the callback takes predence.

SINCE

       3.0

REPORTING BUGS

       Report bugs to <bugs@gnutls.org>.
       Home page: http://www.gnutls.org

COPYRIGHT

       Copyright © 2001-2021 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/