'Allow all users to register'

def register(self, message, host, port):

    (name, toURL, params) = parseAddress(message.headers['to'][0], clean=1)
    contact = None
    if ('contact' in message.headers):
        contact = message.headers['contact'][0]
    if (message.headers.get('expires', [None])[0] == '0'):
        self.unregister(message, toURL, contact)
    else:
        if (contact is not None):
            (name, contactURL, params) = parseAddress(contact, host=host, port=port)
            d = self.registry.registerAddress(message.uri, toURL, contactURL)
        else:
            d = self.registry.getRegistrationInfo(toURL)
        d.addCallbacks(self._cbRegister, self._ebRegister, callbackArgs=(message,), errbackArgs=(message,))
