// NewFirewaller returns a new Firewaller.
func NewFirewaller(st *state.State) *Firewaller {
fw := &Firewaller{
st: st,
environWatcher: st.WatchEnvironConfig(),
machinesWatcher: st.WatchMachines(),
machineds: make(map[string]*machineData),
unitsChange: make(chan *unitsChange),
unitds: make(map[string]*unitData),
portsChange: make(chan *portsChange),
serviceds: make(map[string]*serviceData),
exposedChange: make(chan *exposedChange),
}
go func() {
defer fw.tomb.Done()
fw.tomb.Kill(fw.loop())
}()
return fw
}