NAME

       gnutls_handshake_set_post_client_hello_function - API function

SYNOPSIS

       #include <gnutls/gnutls.h>

       void               gnutls_handshake_set_post_client_hello_function(gnutls_session_t              session,
       gnutls_handshake_post_client_hello_func       func);

ARGUMENTS

       gnutls_session_t session
                   is a gnutls_session_t type.

       gnutls_handshake_post_client_hello_func       func
                   is the function to be called

DESCRIPTION

       This function will set a callback to be called after the client hello has been received  (callback  valid
       in server side only). This allows the server to adjust settings based on received extensions.

       Those  settings  could  be  ciphersuites,  requesting  certificate,  or  anything else except for version
       negotiation (this is done before the hello message is parsed).

       This callback must return 0 on success or a gnutls error code to terminate the handshake.

       Since GnuTLS 3.3.5 the callback is allowed to return GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED  to  put  the
       handshake  on  hold.  In that case gnutls_handshake() will return GNUTLS_E_INTERRUPTED and can be resumed
       when needed.

WARNING

       You should not use this function to terminate the handshake based on client input unless  you  know  what
       you  are  doing. Before the handshake is finished there is no way to know if there is a man-in-the-middle
       attack being performed.

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/