理论:
对于USB接口的设备,现在越来越多了。本篇我们就通过获取一个USB扫描仪设备中的序列号,来介绍如何获取usb设备的一些硬件信息。对于usb设备都是采用HCD0,HCD1,HCD2,HCD3等符号描述的。如下图:
因此,有了这个名字,我们就可以使用CreateFile来打开usb设备。然后使用DeviceIoControl函数与usb设备通讯了。
HCD是host controller driver的简写。需要了解详情的,还要仔细的阅读usb协议。
usb的通讯基本步骤如下图所示:
基本步骤:
1)打开HCD%X
2) 得到上面的USB root hub
3) 遍历usb root hub上连接的usb 设备。获取信息
4)如果有多个usb口,循环前3步。
下面介绍通讯用的几个IOCTL:1)
USB_HCD_DRIVERKEY_NAME ,用于获取USB设备驱动在注册表中的键名。相应的一个结构体是:
typedef struct _USB_HCD_DRIVERKEY_NAME
{
ULONG ActualLength;
WCHAR DriverKeyName[1];
} USB_HCD_DRIVERKEY_NAME, *PUSB_HCD_DRIVERKEY_NAME;2)
IOCTL_USB_GET_ROOT_HUB_NAME,用于获取root hub 键名。使用的结构体,跟上面一样。
typedef struct _USB_ROOT_HUB_NAME
{
ULONG ActualLength;
WCHAR RootHubName[1];
} USB_ROOT_HUB_NAME, *PUSB_ROOT_HUB_NAME;
3)IOCTL_USB_GET_NODE_INFORMATION,用于获取连接在root hub上的节点设备信息。也就是我们接在usb口上的所有usb设备的信息,对应的结构体:
typedef struct _USB_NODE_INFORMATION
{
USB_HUB_NODE NodeType;
union {
USB_HUB_INFORMATION HubInformation;
USB_MI_PARENT_INFORMATION MiParentInformation;
} u;
} USB_NODE_INFORMATION, *PUSB_NODE_INFORMATION;
typedef struct _USB_MI_PARENT_INFORMATION
{
ULONG NumberOfInterfaces;
} USB_MI_PARENT_INFORMATION, *PUSB_MI_PARENT_INFORMATION;
typedef struct _USB_HUB_INFORMATION
{
USB_HUB_DESCRIPTOR HubDescriptor;
BOOLEAN HubIsBusPowered;
} USB_HUB_INFORMATION, *PUSB_HUB_INFORMATION;
typedef struct _USB_HUB_DESCRIPTOR
{
UCHAR bDescriptorLength; // Length of this descriptor
UCHAR bDescriptorType; // Hub configuration type
UCHAR bNumberOfPorts; // number of ports on this hub
USHORT wHubCharacteristics; // Hub Charateristics
UCHAR bPowerOnToPowerGood; // port power on till power good in 2ms
UCHAR bHubControlCurrent; // max current in mA
//
// room for 255 ports power control and removable bitmask
UCHAR bRemoveAndPowerMask[64];
} USB_HUB_DESCRIPTOR, *PUSB_HUB_DESCRIPTOR;
4) IOCTL_USB_GET_NODE_CONNECTION_INFORMATION, 用于获取接在usb口上的单个usb设备的信息,对应的结构体:
typedef struct _USB_NODE_CONNECTION_INFORMATION
{
ULONG ConnectionIndex;
USB_DEVICE_DESCRIPTOR DeviceDescriptor;
UCHAR CurrentConfigurationValue;
BOOLEAN LowSpeed;
BOOLEAN DeviceIsHub;
USHORT DeviceAddress;
ULONG NumberOfOpenPipes;
USB_CONNECTION_STATUS ConnectionStatus;
USB_PIPE_INFO PipeList[0];
} USB_NODE_CONNECTION_INFORMATION, *PUSB_NODE_CONNECTION_INFORMATION;
4)IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, 用于获取usb设备的描述信息。
typedef struct _USB_DEVICE_DESCRIPTOR
{
UCHAR bLength;
UCHAR bDescriptorType;
USHORT bcdUSB;
UCHAR bDeviceClass;
UCHAR bDeviceSubClass;
UCHAR bDeviceProtocol;
UCHAR bMaxPacketSize0;
USHORT idVendor;
USHORT idProduct;
USHORT bcdDevice;
UCHAR iManufacturer;
UCHAR iProduct;
UCHAR iSerialNumber;
UCHAR bNumConfigurations;
} USB_DEVICE_DESCRIPTOR, *PUSB_DEVICE_DESCRIPTOR;
typedef struct _USB_DEVICE_DESCRIPTOR
{
UCHAR bLength;
UCHAR bDescriptorType;
USHORT bcdUSB;
UCHAR bDeviceClass;
UCHAR bDeviceSubClass;
UCHAR bDeviceProtocol;
UCHAR bMaxPacketSize0;
USHORT idVendor;
USHORT idProduct;
USHORT bcdDevice;
UCHAR iManufacturer;
UCHAR iProduct;
UCHAR iSerialNumber;
UCHAR bNumConfigurations;
} USB_DEVICE_DESCRIPTOR, *PUSB_DEVICE_DESCRIPTOR;
typedef enum _USB_CONNECTION_STATUS
{
NoDeviceConnected,
DeviceConnected,
/* failure codes, these map to fail reasons */
DeviceFailedEnumeration,
DeviceGeneralFailure,
DeviceCausedOvercurrent,
DeviceNotEnoughPower,
DeviceNotEnoughBandwidth,
DeviceHubNestedTooDeeply,
DeviceInLegacyHub
} USB_CONNECTION_STATUS, *PUSB_CONNECTION_STATUS;
typedef struct _USB_PIPE_INFO
{
USB_ENDPOINT_DESCRIPTOR EndpointDescriptor;
ULONG ScheduleOffset;
} USB_PIPE_INFO, *PUSB_PIPE_INFO;
typedef struct _USB_ENDPOINT_DESCRIPTOR
{
UCHAR bLength;
UCHAR bDescriptorType;
UCHAR bEndpointAddress;
UCHAR bmAttributes;
USHORT wMaxPacketSize;
UCHAR bInterval;
} USB_ENDPOINT_DESCRIPTOR, *PUSB_ENDPOINT_DESCRIPTOR;
需要注意一点,如果要得到pid,vid,则直接从USB_DEVICE_DESCRIPTOR结构中取出idVendor,idProduct这两项的值就行了。如果要得到序列号,则不是取出 iSerialNumber就可以的。这里的 iSerialNumber仅仅是一个索引值。如果想得到序列号,就需要定义一个结构,然后给设备发送个请求。请求的结构如下图:
代码参照GetStringDescriptor函数。可以根据
iSerialNumber偏移,取出其对应的字符串,存放在上图USB_STRING_DESCRIPTOR结构中。