gnutls_dtls_cookie_send(3)

NAME
gnutls_dtls_cookie_send - API function

SYNOPSIS
#include <gnutls/dtls.h>

int gnutls_dtls_cookie_send(gnutls_datum_t * key, void * client_data, size_t client_data_size, gnutls_dtls_prestate_st * prestate, gnutls_transport_ptr_t ptr, gnutls_push_func push_func);

ARGUMENTS

gnutls_datum_t * key
    is a random key to be used at cookie generation

void * client_data
    contains data identifying the client (i.e. address)

size_t client_data_size
    The size of client's data

gnutls_dtls_prestate_st * prestate
    The previous cookie returned by gnutls_dtls_cookie_verify()

gnutls_transport_ptr_t ptr
    A transport pointer to be used by push_func

gnutls_push_func push_func
    A function that will be used to reply

DESCRIPTION
This function can be used to prevent denial of service attacks to a DTLS server by requiring the client to reply using a cookie sent by this function. That way it can be ensured that a client we allocated resources for (i.e. gnutls_session_t) is the one that the original incoming packet was originated from.

This function must be called at the first incoming packet, prior to allocating any resources and must be succeeded by gnutls_dtls_cookie_verify().

RETURNS
the number of bytes sent, or a negative error code.

SINCE
3.0

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

COPYRIGHT
Copyright © 2001-2017 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/