如何使用本机 WiFi API 访问无线网络参数
使用原生 WiFi API 查询无线网络参数。
引言
在之前的两篇文章中，我向您展示了如何使用 DeviceIOControl 和 Windows Management Instrumentation (WMI) 机制访问 NDIS 迷你端口驱动程序。 本文重点介绍原生 WiFi API。 原生 WiFi API 基本上是为 C/C++ 程序员设计的。 此 API 包含许多用于无线网络连接和配置文件管理的函数。
过去，程序员会使用 DeviceIOControl 或 WMI 查询 OID，以访问无线网络的各种参数。 微软通过引入原生 WiFi API 使其变得更加容易。 现在，我们无需直接查询迷你端口驱动程序。 我们可以像使用 Win32 API 一样，从我们的应用程序中使用 Wifi API。
背景
微软推出了原生 WiFi API，这是一种用于管理无线网络连接和配置文件的全新 API。 运行 Windows Vista 或 Windows XP SP2 的客户端应用程序可以使用此 API。 微软已将其 API 默认集成到 Vista 中。
Windows XP SP2 也支持一部分原生 WiFi API。 但是，用户必须安装额外的软件包/补丁，才能在 Windows XP ASP2 环境中获得此 API 支持。 您可以从 微软网站 了解更多关于 Windows XP SP2 的无线 LAN API 的信息。
使用代码
在下面的示例中，我们将看到如何使用 Wifi API 枚举无线适配器。 Wifi API 提供了许多用于查询无线网络各种参数的函数。
//
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
PlatformInvoke.wifi wifiAPI = new PlatformInvoke.wifi();
wifiAPI.EnumerateNICs();
}
}
}
namespace PlatformInvoke
{
/// <summary >
/// This class encapsulates basic functions required
/// for enumerating wireless adapaters in the system. This class consumes
/// wifi api developed and supported from Microsoft Vista onwards
/// </summary >
class wifi
{
//************************************************************
#region declarations
private const int WLAN_API_VERSION_2_0 = 2; //Windows Vista WiFi API Version
private const int ERROR_SUCCESS = 0;
/// <summary >
/// Opens a connection to the server
/// </summary >
[DllImport("wlanapi.dll", SetLastError = true)]
private static extern UInt32 WlanOpenHandle(UInt32 dwClientVersion,
IntPtr pReserved, out UInt32 pdwNegotiatedVersion,
out IntPtr phClientHandle);
/// <summary >
/// Closes a connection to the server
/// </summary >
[DllImport("wlanapi.dll", SetLastError = true)]
private static extern UInt32 WlanCloseHandle(IntPtr hClientHandle,
IntPtr pReserved);
/// <summary >
/// Enumerates all wireless interfaces in the laptop
/// </summary >
[DllImport("wlanapi.dll", SetLastError = true)]
private static extern UInt32 WlanEnumInterfaces(IntPtr hClientHandle,
IntPtr pReserved, out IntPtr ppInterfaceList);
/// <summary >
/// Frees memory returned by native WiFi functions
/// </summary >
[DllImport("wlanapi.dll", SetLastError = true)]
private static extern void WlanFreeMemory(IntPtr pmemory);
/// <summary >
/// Interface state enums
/// </summary >
public enum WLAN_INTERFACE_STATE : int
{
wlan_interface_state_not_ready = 0,
wlan_interface_state_connected,
wlan_interface_state_ad_hoc_network_formed,
wlan_interface_state_disconnecting,
wlan_interface_state_disconnected,
wlan_interface_state_associating,
wlan_interface_state_discovering,
wlan_interface_state_authenticating
};
/// <summary >
/// Stores interface info
/// </summary >
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct WLAN_INTERFACE_INFO
{
/// GUID->_GUID
public Guid InterfaceGuid;
/// WCHAR[256]
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
public string strInterfaceDescription;
/// WLAN_INTERFACE_STATE->_WLAN_INTERFACE_STATE
public WLAN_INTERFACE_STATE isState;
}
/// <summary >
/// This structure contains an array of NIC information
/// </summary >
[StructLayout(LayoutKind.Sequential)]
public struct WLAN_INTERFACE_INFO_LIST
{
public Int32 dwNumberofItems;
public Int32 dwIndex;
public WLAN_INTERFACE_INFO[] InterfaceInfo;
public WLAN_INTERFACE_INFO_LIST(IntPtr pList)
{
// The first 4 bytes are the number of WLAN_INTERFACE_INFO structures.
dwNumberofItems = Marshal.ReadInt32(pList, 0);
// The next 4 bytes are the index of the current item in the unmanaged API.
dwIndex = Marshal.ReadInt32(pList, 4);
// Construct the array of WLAN_INTERFACE_INFO structures.
InterfaceInfo = new WLAN_INTERFACE_INFO[dwNumberofItems];
for (int i = 0; i < dwNumberofItems; i++)
{
// The offset of the array of structures is 8 bytes past the beginning.
// Then, take the index and multiply it by the number of bytes in the
// structure.
// the length of the WLAN_INTERFACE_INFO structure is 532 bytes - this
// was determined by doing a sizeof(WLAN_INTERFACE_INFO) in an
// unmanaged C++ app.
IntPtr pItemList = new IntPtr(pList.ToInt32() + (i * 532) + 8);
// Construct the WLAN_INTERFACE_INFO structure, marshal the unmanaged
// structure into it, then copy it to the array of structures.
WLAN_INTERFACE_INFO wii = new WLAN_INTERFACE_INFO();
wii = (WLAN_INTERFACE_INFO)Marshal.PtrToStructure(pItemList,
typeof(WLAN_INTERFACE_INFO));
InterfaceInfo[i] = wii;
}
}
}
#endregion
//************************************************************
#region Private Functions
/// <summary >
///get NIC state
/// </summary >
private string getStateDescription(WLAN_INTERFACE_STATE state)
{
string stateDescription=string.Empty;
switch (state)
{
case WLAN_INTERFACE_STATE.wlan_interface_state_not_ready:
stateDescription = "not ready to operate";
break;
case WLAN_INTERFACE_STATE.wlan_interface_state_connected:
stateDescription = "connected";
break;
case WLAN_INTERFACE_STATE.wlan_interface_state_ad_hoc_network_formed:
stateDescription = "first node in an adhoc network";
break;
case WLAN_INTERFACE_STATE.wlan_interface_state_disconnecting:
stateDescription = "disconnecting";
break;
case WLAN_INTERFACE_STATE.wlan_interface_state_disconnected:
stateDescription = "disconnected";
break;
case WLAN_INTERFACE_STATE.wlan_interface_state_associating:
stateDescription = "associating";
break;
case WLAN_INTERFACE_STATE.wlan_interface_state_discovering:
stateDescription = "discovering";
break;
case WLAN_INTERFACE_STATE.wlan_interface_state_authenticating:
stateDescription = "authenticating";
break;
}
return stateDescription;
}
#endregion
//************************************************************
#region Public Functions
/// <summary >
/// enumerate wireless network adapters using wifi api
/// </summary >
public void EnumerateNICs()
{
uint serviceVersion = 0;
IntPtr handle = IntPtr.Zero;
if(WlanOpenHandle(WLAN_API_VERSION_2_0, IntPtr.Zero,
out serviceVersion, out handle) == ERROR_SUCCESS)
{
IntPtr ppInterfaceList = IntPtr.Zero;
WLAN_INTERFACE_INFO_LIST interfaceList;
if (WlanEnumInterfaces(handle, IntPtr.Zero,
out ppInterfaceList) == ERROR_SUCCESS)
{
//Tranfer all values from IntPtr to WLAN_INTERFACE_INFO_LIST structure
interfaceList = new WLAN_INTERFACE_INFO_LIST(ppInterfaceList);
Console.WriteLine("Enumerating Wireless Network Adapters...");
for (int i = 0; i < interfaceList.dwNumberofItems; i++)
Console.WriteLine("{0}-->{1}",
interfaceList.InterfaceInfo[i].strInterfaceDescription,
getStateDescription(interfaceList.InterfaceInfo[i].isState));
//frees memory
if (ppInterfaceList != IntPtr.Zero)
WlanFreeMemory(ppInterfaceList);
}
//close handle
WlanCloseHandle(handle, IntPtr.Zero);
}
}
#endregion
}
}
上面的代码是用 C# 使用平台调用机制编写的，它显示了每个无线适配器的名称及其状态。
结论
本文演示了如何从 C# .NET 应用程序访问 Wifi API。 Wifi API 暴露了许多功能，您可以探索其中的每一个。