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: 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/