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 post,
  gnutls_handshake_hook_func func);


gnutls_session_t session

is a gnutls_session_t structure

unsigned int htype

the gnutls_handshake_description_t of the message to hook at

int post

GNUTLS_HOOK_* depending on when the hook function should be called

gnutls_handshake_hook_func func

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 sent/generation use GNUTLS_HOOK_PRE as post 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.

Note 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.


GNUTLS_E_SUCCESS on success, or an error code.


Report bugs to <>.

General guidelines for reporting bugs:

GnuTLS home page:


The full documentation for gnutls is maintained as a Texinfo manual. If the info and gnutls programs are properly installed at your site, the command

info gnutls

should give you access to the complete manual. As an alternative you may obtain the manual from:


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