NAME         top

       gnutls_handshake_set_hook_function - API function

SYNOPSIS         top

       #include <gnutls/gnutls.h>

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

ARGUMENTS         top

       gnutls_session_t session
                   is a gnutls_session_t type

       unsigned int htype
                   the gnutls_handshake_description_t of the message to hook

       int post    GNUTLS_HOOK_* depending on when the hook function should
                   be called

       gnutls_handshake_hook_func func
                   is the function to be called

DESCRIPTION         top

       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/generated
       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

WARNING         top

       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.

REPORTING BUGS         top

       Report bugs to <>.
       Home page:

COPYRIGHT         top

       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         top

       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 

COLOPHON         top

       This page is part of the GnuTLS (GnuTLS Transport Layer Security
       Library) project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this manual
       page, send it to  This page was obtained from the
       tarball gnutls-3.6.1.tar.xz fetched from
       ⟨⟩ on 2018-02-02.  If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
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gnutls                              3.6.g1nutls_handshake_set_hook_function(3)