'Configures NAT rules for Floating IPs for DVR.'

def _handle_router_snat_rules(self, ex_gw_port, interface_name):

    self.iptables_manager.ipv4['nat'].empty_chain('POSTROUTING')
    self.iptables_manager.ipv4['nat'].empty_chain('snat')
    ex_gw_port = self.get_ex_gw_port()
    if (not ex_gw_port):
        return
    ext_device_name = self.get_external_device_interface_name(ex_gw_port)
    floatingips = self.get_floating_ips()
    if ((not ext_device_name) or (not floatingips)):
        return
    self.iptables_manager.ipv4['nat'].add_rule('snat', '-j    $float-snat')
    rule = self._prevent_snat_for_internal_traffic_rule(ext_device_name)
    self.iptables_manager.ipv4['nat'].add_rule(*rule)
