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gnutls_dtls_cookie_send(3)          gnutls          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: https://www.gnutls.org

COPYRIGHT
       Copyright (C) 2001- 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/local/share/doc/gnutls/ directory does not contain the HTML
       form visit

       https://www.gnutls.org/manual/

gnutls                               3.7.9          gnutls_dtls_cookie_send(3)