NAME

       gnutls_srp_set_server_credentials_function - API function

SYNOPSIS

       #include <gnutls/gnutls.h>

       void           gnutls_srp_set_server_credentials_function(gnutls_srp_server_credentials_t           cred,
       gnutls_srp_server_credentials_function * func);

ARGUMENTS

       gnutls_srp_server_credentials_t cred
                   is a gnutls_srp_server_credentials_t type.

       gnutls_srp_server_credentials_function * func
                   is the callback function

DESCRIPTION

       This function can be used to set a callback to retrieve  the  user's  SRP  credentials.   The  callback's
       function form is:

       int  (*callback)(gnutls_session_t,  const char* username, gnutls_datum_t *salt, gnutls_datum_t *verifier,
       gnutls_datum_t *generator, gnutls_datum_t *prime);

        username contains the actual username.  The  salt ,  verifier ,  generator and  prime must be filled  in
       using the gnutls_malloc(). For convenience  prime and  generator may also be one of the static parameters
       defined in gnutls.h.

       Initially,  the  data  field  is NULL in every gnutls_datum_t structure that the callback has to fill in.
       When the callback is done GnuTLS deallocates all of those buffers which are non-NULL, regardless  of  the
       return value.

       In  order  to  prevent  attackers from guessing valid usernames, if a user does not exist, g and n values
       should be filled in using a random user's parameters. In that case the callback must return  the  special
       value  (1).  See gnutls_srp_set_server_fake_salt_seed too.  If this is not required for your application,
       return a negative number from the callback to abort the handshake.

       The callback function will only be called once per handshake.  The callback function should return  0  on
       success, while -1 indicates an error.

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_srp_set_server_credentials_function(3)