NAME

gnutls_rehandshake - API function

SYNOPSIS

#include <gnutls/gnutls.h>

int gnutls_rehandshake(gnutls_session_t session);

ARGUMENTS

gnutls_session_t session: is a gnutls_session_t type.

DESCRIPTION

This function can only be called in server side, and instructs a TLS 1.2 or earlier client to renegotiate parameters (perform a handshake), by sending a hello request message.

If this function succeeds, the calling application should call gnutls_record_recv() until GNUTLS_E_REHANDSHAKE is returned to clear any pending data. If the GNUTLS_E_REHANDSHAKE error code is not seen, then the handshake request was not followed by the peer (the TLS protocol does not require the client to do, and such compliance should be handled by the application protocol).

Once the GNUTLS_E_REHANDSHAKE error code is seen, the calling application should proceed to calling gnutls_handshake() to negotiate the new parameters.

If the client does not wish to renegotiate parameters he may reply with an alert message, and in that case the return code seen by subsequent gnutls_record_recv() will be GNUTLS_E_WARNING_ALERT_RECEIVED with the specific alert being GNUTLS_A_NO_RENEGOTIATION. A client may also choose to ignore this request.

Under TLS 1.3 this function is equivalent to gnutls_session_key_update() with the GNUTLS_KU_PEER flag. In that case subsequent calls to gnutls_record_recv() will not return GNUTLS_E_REHANDSHAKE, and calls to gnutls_handshake() in server side are a no-op.

This function always fails with GNUTLS_E_INVALID_REQUEST when called in client side.

RETURNS

GNUTLS_E_SUCCESS on success, otherwise a negative error code.

REPORTING BUGS

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

COPYRIGHT

Copyright © 2001-2022 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.