DOKK / manpages / debian 12 / gnutls-doc / gnutls_handshake_set_hook_function.3.en
gnutls_handshake_set_hook_function(3) gnutls gnutls_handshake_set_hook_function(3)

gnutls_handshake_set_hook_function - API function

#include <gnutls/gnutls.h>

void gnutls_handshake_set_hook_function(gnutls_session_t session, unsigned int htype, int when, gnutls_handshake_hook_func func);

is a gnutls_session_t type
the gnutls_handshake_description_t of the message to hook at
GNUTLS_HOOK_* depending on when the hook function should be called
is the function to be called

This function will set a callback to be called after or before the specified handshake message has been received or generated. This is a generalization of gnutls_handshake_set_post_client_hello_function().

To call the hook function prior to the message being generated or processed use GNUTLS_HOOK_PRE as when parameter, GNUTLS_HOOK_POST to call after, and GNUTLS_HOOK_BOTH for both cases.

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

To hook at all handshake messages use an htype of GNUTLS_HANDSHAKE_ANY.

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.

Report bugs to <bugs@gnutls.org>.
Home page: https://www.gnutls.org

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3.7.9 gnutls