switch network {
	case "ip", "ip4", "ip6":
	default:
		return nil, errNoAvailableAddress
	}
	if ifi == nil || ifi.Flags&net.FlagUp == 0 || ifi.Flags&net.FlagMulticast == 0 {
		return nil, errNoAvailableAddress
	}
	ip, ok := hasRoutableIP(network, ifi)
	if !ok {
		return nil, errNoAvailableAddress
	}
	return ip, nil
}