在實(shí)際應(yīng)用中，復(fù)雜的網(wǎng)絡(luò)狀況可能讓設(shè)備網(wǎng)絡(luò)產(chǎn)生異常（比如IP沖突），從而無(wú)法正常網(wǎng)絡(luò)通信。通過(guò)重啟設(shè)備可以恢復(fù)網(wǎng)絡(luò)，本文介紹另外一個(gè)方法，在應(yīng)用層不斷電的情況下快速重置網(wǎng)絡(luò)，恢復(fù)網(wǎng)絡(luò)通信。

手動(dòng)重置網(wǎng)絡(luò)

進(jìn)入板子控制面板->網(wǎng)絡(luò)和撥號(hào)連接，可以看到板子現(xiàn)有網(wǎng)口的網(wǎng)絡(luò)連接圖標(biāo)，下圖以EM9287為例，EM9287有兩個(gè)網(wǎng)口，分別為ENET1和ENET2。

右鍵點(diǎn)擊需要重置的網(wǎng)口圖標(biāo)，先選擇禁用，可以看到圖標(biāo)顯示X，同時(shí)板子網(wǎng)絡(luò)燈停止閃爍。

再次右鍵點(diǎn)擊該圖標(biāo)，選擇啟用，圖標(biāo)恢復(fù)連接顯示，可以觀察到板子網(wǎng)絡(luò)燈重新亮起。

代碼重置網(wǎng)絡(luò)

引用pw.h頭文件，添加定義板子DEVICEIOCONTROL的相關(guān)宏定義。

#defineDD_NDIS_DEVICE_NAME TEXT("NDS0:")

#defineNDISPWR_DEVICE_NAME TEXT("NPW1:")

#define_NDIS_CONTROL_CODE(request,method) \

CTL_CODE(FILE_DEVICE_PHYSICAL_NETCARD, request, method, FILE_ANY_ACCESS)

#defineWINCE_IOCTL_START 8

#defineIOCTL_NDIS_BIND_ADAPTER _NDIS_CONTROL_CODE( WINCE_IOCTL_START+4, METHOD_OUT_DIRECT )

#defineIOCTL_NDIS_UNBIND_ADAPTER _NDIS_CONTROL_CODE( WINCE_IOCTL_START+5, METHOD_OUT_DIRECT )

#defineIOCTL_NDIS_GET_ADAPTER_BINDINGS _NDIS_CONTROL_CODE( WINCE_IOCTL_START+8, METHOD_OUT_DIRECT )

#define FSCTL_NDISPWR_BASE FILE_DEVICE_NETWORK

#define_NDISPWR_CTL_CODE(_Function, _Method, _Access) \

CTL_CODE(FSCTL_NDISPWR_BASE, _Function, _Method, _Access)

#defineIOCTL_NPW_SAVE_POWER_STATE \

_NDISPWR_CTL_CODE(0x200, METHOD_BUFFERED, FILE_ANY_ACCESS)

首先調(diào)用電源管理設(shè)備NPW，通知它關(guān)閉網(wǎng)口電源（這里以ENET1為例）

hNdisPwr = CreateFile(NDISPWR_DEVICE_NAME, 0, 0, NULL, OPEN_EXISTING,

FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED, INVALID_HANDLE_VALUE);

SavePowerState.CePowerState = D4;

SavePowerState.pwcAdapterName = L”ENET1”;

bRet = DeviceIoControl(

hNdisPwr,

IOCTL_NPW_SAVE_POWER_STATE,

&SavePowerState,

sizeof(NDISPWR_SAVEPOWERSTATE),

NULL,

0x00,

NULL,

NULL);

CloseHandle(hNdisPwr);

如果網(wǎng)口有自己的電源管理，那么那么還應(yīng)該調(diào)用以下代碼。還是以ENET1為例，這里的字符串一定得是{98C5250D-C29A-4985-AE5F-AFE5367E5006}\ENET1這樣的，并且需要兩個(gè)\0結(jié)尾！

TCHAR szName[MAX_PATH]=L”ENET1”;

int nChars;

nChars = _sntprintf(

szName,

MAX_PATH-1,

_T("%s\\%s"),

PMCLASS_NDIS_MINIPORT,

wcName);

szName[MAX_PATH-1]=0;

DWORD dwRet;

dwRet = SetDevicePower(szName, POWER_NAME, D4);

通知系統(tǒng)UNBIND網(wǎng)口

BOOL DoNdisIOControl(DWORD dwCommand, LPVOID pInBuffer,

DWORD cbInBuffer, LPVOID pOutBuffer,

DWORD * pcbOutBuffer)

{

HANDLE hNdis;

BOOL fResult = FALSE;

hNdis = ::CreateFile(DD_NDIS_DEVICE_NAME, GENERIC_READ | GENERIC_WRITE,

FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,

0, NULL);

if(INVALID_HANDLE_VALUE != hNdis)

{

fResult = DeviceIoControl(hNdis, dwCommand, pInBuffer, cbInBuffer,

pOutBuffer, (pcbOutBuffer ? *pcbOutBuffer : 0),

pcbOutBuffer, NULL);

CloseHandle(hNdis);

}

returnfResult;

}

…

bRet = DoNdisIOControl(

IOCTL_NDIS_UNBIND_ADAPTER,

wcName,

(_tcslen(wcName)+2) *sizeof(TCHAR),

NULL,

NULL);

查詢網(wǎng)絡(luò)，確認(rèn)一下禁用網(wǎng)絡(luò)是否成功

bRet = DoNdisIOControl(

IOCTL_NDIS_GET_ADAPTER_BINDINGS,

wcName,

(_tcslen(wcName)+1) *sizeof(TCHAR),

multiSz,

&cbBuffer);

return(multiSz[0] != L'\0');

讓板子網(wǎng)口重新上電，這里上電不能直接使用D0，只能使用默認(rèn)值PwrDeviceUnspecified

hNdisPwr = CreateFile(NDISPWR_DEVICE_NAME, 0, 0, NULL, OPEN_EXISTING,

FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED, INVALID_HANDLE_VALUE);

SavePowerState.CePowerState = PwrDeviceUnspecified;

SavePowerState.pwcAdapterName = L”ENET1”;

bRet = DeviceIoControl(

hNdisPwr,

IOCTL_NPW_SAVE_POWER_STATE,

&SavePowerState,

sizeof(NDISPWR_SAVEPOWERSTATE),

NULL,

0x00,

NULL,

NULL);

CloseHandle(hNdisPwr);

TCHAR szName[MAX_PATH]=L”ENET1”;

int nChars;

nChars = _sntprintf(

szName,

MAX_PATH-1,

_T("%s\\%s"),

PMCLASS_NDIS_MINIPORT,

wcName);

szName[MAX_PATH-1]=0;

DWORD dwRet;

dwRet = SetDevicePower(szName, POWER_NAME, PwrDeviceUnspecified);

通知系統(tǒng)BIND網(wǎng)口

bRet = DoNdisIOControl(

IOCTL_NDIS_BIND_ADAPTER,

wcName,

(_tcslen(wcName)+2) *sizeof(TCHAR),

NULL,

NULL);

查詢網(wǎng)絡(luò)，確認(rèn)一下網(wǎng)絡(luò)啟動(dòng)是否成功

bRet = DoNdisIOControl(

IOCTL_NDIS_GET_ADAPTER_BINDINGS,

wcName,

(_tcslen(wcName)+1) *sizeof(TCHAR),

multiSz,

&cbBuffer);

return(multiSz[0] != L'\0');

例程里已經(jīng)將以上代碼封裝到enet.h，使用以下代碼可以簡(jiǎn)單重置網(wǎng)絡(luò)

#include"enet.h"

Void ResetENET（）

{

EnableENET(FALSE);

EnableENET(TRUE);

}

在重置網(wǎng)絡(luò)前，建議先關(guān)閉該網(wǎng)口現(xiàn)有的socket連接

整個(gè)重置過(guò)程是通過(guò)電源管理將網(wǎng)口斷電，然后通知系統(tǒng)將網(wǎng)絡(luò)UNBIND。然后重新給網(wǎng)口上電，再通知系統(tǒng)將網(wǎng)絡(luò)BIND。通過(guò)網(wǎng)絡(luò)燈可以看到，硬件PHY是有復(fù)位的，即網(wǎng)絡(luò)在硬件層進(jìn)行了復(fù)位。文中提到的例程，可以通過(guò)聯(lián)系英創(chuàng)工程師獲得。