code: func (daemon *Daemon) Subnets() ([]net.IPNet, []net.IPNet) {
  	var v4Subnets []net.IPNet
  	var v6Subnets []net.IPNet
  
  	managedNetworks := daemon.netController.Networks()
  
  	for _, managedNetwork := range managedNetworks {
  		v4infos, v6infos := managedNetwork.Info().IpamInfo()
  		for _, info := range v4infos {
  			if info.IPAMData.Pool != nil {
  				v4Subnets = append(v4Subnets, *info.IPAMData.Pool)
  			}
  		}
  		for _, info := range v6infos {
  			if info.IPAMData.Pool != nil {
  				v6Subnets = append(v6Subnets, *info.IPAMData.Pool)
  			}
  		}
  	}
  
  	return v4Subnets, v6Subnets
  }
docs: // Subnets return the IPv4 and IPv6 subnets of networks that are manager by Docker.