KR20070017609A - Method of managing USB devices - Google Patents

Abstract

The present invention relates to a method of controlling the operation of a USB device, and more particularly, a small security controller is installed in a USB port to allow an operation between the USB device and the USB host controller by the small security controller. In this case, the operation mode can be controlled by allowing the I / O in a limited manner. When the input / output of the USB device is limited because the timer is built in the security controller, the data is transmitted by the corresponding byte. The data line can be controlled at millisecond intervals while calculating the required time, and if the USB device is allowed, the USB device and the host controller can be directly connected by operating a relay built in the security controller. In addition, the use of security controllers reduces the cost of implementing devices that control the behavior of USB devices.

USB, Device Driver, Security Controller, USB System Software, USB Host Controller, USB Device Hardware, CPU, Flash Memory, RAM, Relay, Timer, USB Control, Security Function.

Description

      How to control the behavior of USB devices {Method of managing USB devices}

1 is a block diagram for a conventional USB connection.

Figure 2 is a block diagram for a USB connection added to the security function in the USB control system added security controller according to an embodiment of the present invention.

3 is a block diagram showing the structure of a security controller applied to the USB control system to which the security controller is added according to an embodiment of the present invention.

4 is a diagram illustrating a device class used to control a USB device in a USS control system to which a security controller is added according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a device descriptor used to control a USB device in a USB control system to which a security controller is added according to an embodiment of the present invention. FIG.

FIG. 6 is a diagram illustrating an interface class used to control a USB device in a USS control system to which a security controller is added according to an embodiment of the present invention. FIG.

7 is a flowchart illustrating a process in which a USB device having a security controller function added to a host is connected to a connector and operated according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: host 200: device

101: device driver 102, 203: USB system software

103, 204: USB host controller 104, 205: USB device hardware

202: security controller 202-1: CPU

202-2: Timer 202-3: Flash Memory

202-4: RAM 202-5: Relay

The present invention relates to a method of controlling the operation of a USB device, and more particularly, a small security controller is installed in a USB port to allow an operation between the USB device and the USB host controller by the small security controller. In this case, the operation mode can be controlled by allowing the I / O in a limited manner. When the input / output of the USB device is limited because the timer is built in the security controller, the data is transmitted by the corresponding byte. The data line can be controlled at millisecond intervals while calculating the time required.If the USB device is allowed, the relay built into the security controller can be operated to directly connect the USB device to the host controller. To control the behavior of the USB device. It relates to a method for controlling the operation of the device yueseubi easily be reduced.

The Universal Serial Bus (USB) provides a simple way to integrate computers and phones, known as the computer telephone interface (CTI), and is available to seven companies: Compaq, DEC, IBM, Intel, Microsoft, NEC, and Nortel. It is a universal bus standard developed by the company. As the protocol evolved, it expanded to the concept of easily integrating up to 127 peripherals on a PC and was released in the USB1.0 specification. This specification has the following major goals for USB technology:

First of all, I wanted to suggest that the PC peripherals are easy to use and that they can support transmission at a speed of 12 Mbps at a low price, and full support for real-time data for voice and compressed video, and synchronous data in mixed mode. Development of new devices that increase PC performance and provide a standard environment that enables protocol flexibility for transmission and asynchronous messages, integration into useful device technologies, understanding of various PC configurations and form factors, and rapid deployment to products. The back was it.

Because of this goal, USB eventually works under the concept of master / slave and directly between the host and each peripheral or through a hub, which basically consists of a serial bus or serial bus. It should be noted, however, that this is not to be confused with the basic RS-232 serial environment we use on PCs, and it does not replace the PCI bus. Ease-of-use for expansion to PC peripherals, which was the first goal, is an important feature of USB that makes it easy to connect or configure a peripheral to a host PC using a true plug-and-play concept that saves you the trouble of opening your computer's case. It is.

Due to this. All connected peripherals can be connected externally via a direct USB port on the host or a USB hub device, and have a full speed of 12 Mbps and a low speed of 1.5 Mbps to use these peripherals. Regarding this USB specification, seven USB Core companies joined in 1994 to form the Windows Hardware Engineering Conference (WinHEC) and the USB implementers Forum (USB-IF) in 1995. As a result, the USB 1.0 specification was announced on January 15, 1996, and the first USB products were introduced to Comdex. That solved the problems of 1.0 protocol and the USB 1.1 protocol was re-released on September 23, 1998 for the practical use of peripherals. With the announcement of the USB 1.1 specification, chipsets supporting USB ports were released by companies such as Intel, VIA, SiS, and ALi, and started to be installed on the motherboard by default. However, Microsoft's Windows was unable to support this hardware advancement, resulting in various problems, and it started to be supported properly in OSR 2.1 of Windows 95. More realistically, however, it should be seen as supported by Windows 98, and Windows 98 is also a major version up from the SE version that includes drivers for USB peripherals.

Meanwhile, peripheral devices supporting USB have been produced in recent years due to the advantages of USB and global standards.

The first is a USB communication device. Originally, modems use ISA and PCI. These modems are internal, and external modems include serial and PCMCIA. In recent years, USB has emerged. USB modems have the advantage of being easy to carry and do not require a separate power adapter, easy connection, and other communication devices include a USB hub and a USB cable. The hub is an extension of several USB ports, and the cable is a device that connects two PCs. Using a USB cable allows two PCs to be connected to each other without a separate LAN card for networking.

Secondly, USB input devices such as keyboards, mice, and joysticks are most ideal as USB devices. These devices can be used by simply plugging them in without installing drivers. The keyboard and mouse can also be used with a keyboard and mouse connected to the PS / 2 port. In the case of joystick, you can connect several joysticks. By default, the joystick connects to the joystick port provided on the sound card and, of course, there is only one port, so only one joystick can be connected. But with USB joysticks, you can connect multiple devices at the same time.

Third, as USB storage devices, USB type storage devices are increasing due to the fast USB transfer speed. CD-Rs, hard disks, ZIP drives, super disks and smart media are available via USB. In the case of hard disks, USB hard disks are not released, but devices that convert EIDE hard disks into external hard disk cases and convert them to USB are used. CD-R is rated at 4x speed due to USB's limitation of transmission speed, but it has been evaluated quite stably. It is reasonable to use a CD-R while carrying it on various computers, and a storage medium such as ZIP is a good option for USB, but has a disadvantage of being expensive compared to other interfaces.

Fourth, as a multimedia device supporting USB, there are a TV receiver, a speaker, and a video capture card. Sound cards are also available with a USB interface. The advantage of these devices is that there is no loss of sound quality or picture quality. In the case of a PCI sound card, various devices inside the PC create noise and degrade the sound quality. On the other hand, since USB sound cards are connected by cables from the outside, there is no noise and sound quality deterioration, and USB radio or TV receiving cards also have no deterioration in image quality or sound quality. These devices are mainly suitable for notebooks and are suitable for use while carrying.

With the widespread use of the USB standard for easy and convenient communication with various peripherals, the issue of information security has become a serious issue for companies. Due to the sharp drop in the price of large-capacity flash memory, digital cameras and portable phones with built-in flash memory can be connected to external USB drives and USB ports, which can be connected to hundreds of megabytes of capacity, but with the capacity of a disposable lighter. The illegal stealing of internal company information through the installed USB port is a big problem.

Therefore, by installing a small security controller in the USB port, the operation mode is controlled by allowing the input and output between the USB device and the USB host controller when the USB device is allowed by the small security controller, when the USB device is prohibited, or when the input is restricted. In the case of restricting the input / output of the USB device, it is possible to calculate the time required to transfer the data by the byte and control the data line at the interval of milliseconds, and if the USB device is allowed, built in the security controller Currently, there is an urgent need to apply a control method for directly connecting a USB device and a host controller by operating a relay.

Accordingly, an object of the present invention is to solve the above problems, it is equipped with a small security controller in the USB port to allow the operation of the USB device and the USB host controller between the USB device is allowed by the small security controller In this case, the present invention provides a method of controlling the operation of a USB device that can control an operation mode in a case where the input and output is prohibited, and the input / output is restricted.

Another object of the present invention is a built-in timer in the security controller is limited to the input and output of the USB device to calculate the time required to transfer the data by the byte, while controlling the data line at millisecond interval It is to provide a method for controlling the operation of the device.

Another object of the present invention is to provide a method for controlling the operation of a USB device that can directly connect the USB device and the host controller by operating a relay embedded in the security controller when the USB device is allowed.

Yet another object of the present invention is to provide a method for controlling the operation of a USB device, in which a cost is reduced in implementing a device for controlling the operation of the USB device because a security controller is used.

In order to achieve the above object of the present invention, a method of controlling the operation of a USB device includes a manufacturer ID of a USB device by issuing a Get_Descriptor (device) command and a Get_Descriptor (configuration) command when the USB device is inserted into a connector. (A) finding a product ID and an interface class ID; (B) determining whether the USB device is allowed, if it is prohibited, or if the input / output is allowed in a limited manner by comparing the information with the prohibited USB device stored in the flash memory; If the USB device is allowed, the small security controller issues a RESET command to return the connected USB device to the initial state and operates a relay to directly connect the USB device to the host controller, and the USB device is prohibited. The security controller issues a RESET command to the USB device and sends a STATUS = 'STALL' command to the host to indicate that the device is unreachable.If the USB device allows limited input and output, the data line When it is loaded, the security controller calculates the time it takes to transfer data by the corresponding byte through its timer, blocks the data line when the time elapses, sends STATUS = 'STALL' signal to the host, and issues a RESET command to the USB device. (C) blocking the connection.

In the present invention, if the USB device of step (c) is allowed, the host controller performs a normal operation by issuing a Get_Descriptor (device) and Get_Descriptor (configuration) command after directly connecting the USB device and the host controller. It characterized in that it further comprises.

In the present invention, when the USB device of step (c) allows limited input and output, the transfer rate of the data according to the byte is calculated in terms of 12M bits / second is determined according to the USB protocol.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram for a conventional USB connection, Figure 2 is a block diagram for a USB connection with added security function in the USB control system to which the security controller is added according to an embodiment of the present invention, Figure 3 is 4 is a block diagram illustrating a structure of a security controller applied to a USS control system to which a security controller is added, and FIG. 4 is a USS device in a USS control system to which a security controller is added according to an embodiment of the present invention. FIG. 5 is a diagram illustrating a device class used to control a device class, and FIG. 5 is a diagram illustrating a device descriptor used to control a USB device in a USB control system to which a security controller is added according to an embodiment of the present invention. 6 is a USS to which a security controller is added according to an embodiment of the present invention. A diagram for explaining an interface class which is used to control the device in yueseubi control system.

As shown in Figs. 1 to 6, Fig. 1 shows an example of a connection between a host and a device through a general USB. All the above USB devices are configured to communicate with the host in a certain procedure according to the USB protocol. The difference between the USB protocol and other devices is that the device drivers that drive existing devices directly control the device, but the device driver 101 according to the USB protocol does not control the device directly and always uses the USB system software 102 and the USB host controller. Only via 103 can communicate with the USB device 104 and instruct a desired operation. Therefore, in the present invention, as shown in FIG. 2 in the upper layer of the USB system software, the security controller 202 is provided to control the connection and operation of the USB device.

As shown in FIG. 3, the security controller 202 is an object that is on top of the USB system software 203 and communicates with the host side. The security controller may be implemented in software or hardware. 3 shows the structure of a security controller, which is composed of its own CPU, timer, relay, RAM, and flash memory. The CPU 202-1 acquires descriptor information and accordingly executes control of the USB device, and the timer 202-2 makes it possible to control the data line at millisecond intervals, and the flash The memory 202-3 allows only the security administrator to store a list of allowed and restricted devices and to modify the list so that the general user cannot arbitrarily modify this data. It plays a role to make information security consistent and flexible. The RAM 202-4 is any allowed memory, and the relay 202-5 allows direct connection of the USB device 205 and the host controller 204.

As shown in FIG. 4, the USB protocol classifies various types of USB devices having similar functions into classes. In the USB implementers forum (hereinafter, referred to as USB IF) that created the USB protocol, various types of devices are divided into seven classes. The contents are shown in FIG. 4. According to the USB protocol, devices that do not conform to the class specified by the USB IF in advance cannot be recognized by the host, and thus are not compatible. Therefore, the manufacturer of the USB device must select a class that conforms to the USB protocol and manufacture the USB device manufactured by the company. It must be able to write it down and provide class information when the host requests device information from the USB device.

In addition, the USB device has a device descriptor in the internal memory, which is shown in FIG. As shown in Fig. 5, the third field of the device descriptor is bcdUSB. Since the bcdUSBUSB can identify the USB specification number supported by the USB device, the data rate can be known by the specification number. The fourth field of the device descriptor is the USB class code. The class to which the USB device belongs is recorded. The eighth component is the vendor ID, which is the manufacturer's unique number, and the ninth component is the product ID, the identification number of the product.

In addition, in the interface descriptor, what kind of work the device does is recorded in the interface class, and it can be seen from the interface class diagram of FIG. For example, interface class 1 is an audio device, and 7 is a printer device.

7 is a flowchart illustrating a process in which a USB device having a security controller function added to a host is connected to a connector and operated according to an embodiment of the present invention.

     As shown in FIG. 7, when the USB device is inserted into the connector, the small security controller 202 acts as a host controller. More specifically, the small security controller 202 acts as a host controller. In detail, the Get_Descriptor (device) command and the Get_Descriptor (configuration) command are issued. The manufacturer ID, product ID, and interface class ID are found (S1). It is determined whether the USB device is allowed, if it is prohibited, or if the I / O is limitedly allowed by comparing the information with the prohibited USB device stored in the flash memory (S2).

First, in the case of the allowed device (S2-1), if the connected USB device is not the prohibited device, the small security controller 202 issues a RESET command to return the connected USB device to the initial state and relay ( 202-5 is operated to directly connect the USB device 205 and the host controller 204 (S2-1-1). Subsequently, the real host controller issues Get_Descriptor (device) and Get_Descriptor (configuration) commands to enable normal operation (S2-1-2).

In addition, in the case of the prohibited device (S2-2), if the connected USB device is the mass storage device of interface class No. 7, for example, the small security controller issues a RESET command to the USB device, and the STATUS = ' STALL 'command is sent to inform the user that the connection is not possible (S2-2-1).

In addition, in the case of allowing limited input / output (S2-3), even if the device is prohibited from access, it may be necessary to provide a limited type of input / output for a specific application such as an accredited certificate. In this case, I / O should allow 4K bytes of data. In the above case, in response to the Get_Descriptor (device) command, as shown in FIG. 5, the USB specification number supported by the device can be identified by the bcdUSB, which is the third field of the device descriptor transmitted by the USB device. The transmission speed of the data can be known. For example, if the device supports USB 2.0 and supports full speed mode, the data transfer rate is set to 12Mbits / sec according to the USB protocol. Therefore, the time required to transfer 4K bytes of data is calculated in terms of bytes. Will take 31.25 milliseconds (msec). Therefore, the compact security controller 202 can control the data line at millisecond intervals by its timer 202-2. More specifically, when data is loaded on the data line, the small security controller 202 calculates the elapsed time using its own timer, and blocks the data line after 32 milliseconds (S2-3-1). 'Send a signal and issue a RESET command to the device to close the connection (S2-3-2). In some cases, 10K bytes of input and output must be allowed. In this case, 78.123 milliseconds is the limit value. Therefore, data is blocked based on 79 milliseconds.

It will be appreciated by those skilled in the art that the present invention is not limited to the above embodiments, and various modifications and changes can be made without departing from the spirit of the present invention. .

As described above, the method of controlling the operation of the present invention UBS apparatus has the following effects.

First, the present invention is to install a small security controller in the USB port, the operation between the USB device and the USB host controller when the USB device is allowed by the small security controller, when prohibited, if limited to allow input and output You can control the operation mode.

Secondly, in the present invention, when the timer is embedded in the security controller, when the input / output of the USB device is limited, the data line may be controlled at millisecond intervals while calculating the time required to transmit data by the corresponding byte.

Third, when the USB device is allowed, the USB device may be directly connected to the host controller by operating a relay built in the security controller.

Fourth, since the present invention uses a security controller, the cost is reduced to implement a device for controlling the operation of the USB device.

Claims (3)

In the method of controlling the operation of the USB device, When the USB device is inserted into the connector, the small security controller issuing a Get_Descriptor (device) command and a Get_Descriptor (configuration) command to find a manufacturer ID, a product ID, an interface class ID, etc. of the USB device; (B) determining whether the USB device is allowed, if it is prohibited, or if the input / output is allowed in a limited manner by comparing the information with the prohibited USB device stored in the flash memory; If the USB device is allowed, the small security controller issues a RESET command to return the connected USB device to the initial state and operates a relay to directly connect the USB device to the host controller. If the USB device is prohibited, the security controller issues a RESET command to the USB device and sends a STATUS = 'STALL' command to the host to inform the user that the device cannot be accessed. When the USB device permits limited input and output, when the data is loaded on the data line, the security controller calculates the time required to transmit the data by the corresponding byte through its timer, and blocks the data line after the corresponding time has elapsed. And (c) sending a STATUS = 'STALL' signal and issuing a RESET command to the USB device to disconnect the connection. The method of claim 1, If the USB device of step (c) is allowed, the method further includes the step of directly connecting the USB device and the host controller and executing a normal operation by issuing a Get_Descriptor (device) and Get_Descriptor (configuration) command. To control the operation of the USB device. The method of claim 1, When the USB device of step (c) allows limited input and output, the transfer rate of the data according to the byte is calculated in terms of 12M bits / second in accordance with the USB protocol to control the operation of the USB device Way.

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