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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. gnutls 3.7.9 gnutls_dtls_cookie_send(3)