SSL_CTX_callback_ctrl
long SSL_CTX_callback_ctrl(SSL_CTX *, int, void (*)(void));
SSL_CTX_callback_ctrl(ctx, SSL_CTRL_SET_TLSEXT_SERVERNAME_CB, \
SSL_CTX_callback_ctrl(ssl, SSL_CTRL_SET_TLSEXT_STATUS_REQ_CB, \
SSL_CTX_callback_ctrl(ssl, SSL_CTRL_SET_TLSEXT_TICKET_KEY_CB, \
SSL_CTX_callback_ctrl(ctx, SSL_CTRL_SET_MSG_CALLBACK, (void (*)(void))cb);
SSL_CTX_callback_ctrl(ctx, SSL_CTRL_SET_NOT_RESUMABLE_SESS_CB,
SSL_CTX_callback_ctrl(ctx, SSL_CTRL_SET_TMP_DH_CB, (void (*)(void))dh);