delphi - 使用 Delphi 检测 Internet 连接激活

Question

我使用 3G 无线网卡已经有一段时间了，每次连接时，我的防病毒软件都会启动更新。

我想知道我可以使用哪些 Win32 API 函数集来获取有关 Internet 连接事件的通知或查询？

并且是否已经有一组用于 Delphi 的移植标头？

Answer 1

我参与了一个项目，只要他们通过 VPN 连接我们的网络，就可以运行用户的登录脚本。为此，我编写了一个辅助单元来检索适配器信息并将其存储到一个简单的记录中。

然后我设置了一个注册表通知，请参阅此处了解如何在 Delphi 中执行此操作

注册表通知已打开HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces。每次 Windows 获得新的 IP 地址或对适配器连接信息进行任何类型的更改时，都会触发此通知事件。当此事件触发时，我调用了该函数（在下面的代码中）以检索有关适配器的更新信息。我将这个新信息与我之前记录的信息进行了比较……这意味着我必须保存之前的适配器信息查询才能知道是否发生了变化。

无论如何，这是我的助手单元：

unit uAdapterInfo;

interface

uses
  Classes,
  SysUtils;

const
  MAX_INTERFACE_NAME_LEN = $100;
  ERROR_SUCCESS   = 0;
  MAXLEN_IFDESCR  = $100;
  MAXLEN_PHYSADDR = 8;

  MIB_IF_OPER_STATUS_NON_OPERATIONAL = 0;
  MIB_IF_OPER_STATUS_UNREACHABLE = 1;
  MIB_IF_OPER_STATUS_DISCONNECTED = 2;
  MIB_IF_OPER_STATUS_CONNECTING  = 3;
  MIB_IF_OPER_STATUS_CONNECTED   = 4;
  MIB_IF_OPER_STATUS_OPERATIONAL = 5;

  MIB_IF_TYPE_OTHER    = 1;
  MIB_IF_TYPE_ETHERNET = 6;
  MIB_IF_TYPE_TOKENRING = 9;
  MIB_IF_TYPE_FDDI     = 15;
  MIB_IF_TYPE_PPP      = 23;
  MIB_IF_TYPE_LOOPBACK = 24;
  MIB_IF_TYPE_SLIP     = 28;

  MIB_IF_ADMIN_STATUS_UP      = 1;
  MIB_IF_ADMIN_STATUS_DOWN    = 2;
  MIB_IF_ADMIN_STATUS_TESTING = 3;

  _MAX_ROWS_ = 20;
  ANY_SIZE   = 1;


type
  MIB_IFROW = record
    wszName:    array[0 .. (MAX_INTERFACE_NAME_LEN * 2 - 1)] of ansichar;
    dwIndex:    longint;
    dwType:     longint;
    dwMtu:      longint;
    dwSpeed:    longint;
    dwPhysAddrLen: longint;
    bPhysAddr:  array[0 .. (MAXLEN_PHYSADDR - 1)] of byte;
    dwAdminStatus: longint;
    dwOperStatus: longint;
    dwLastChange: longint;
    dwInOctets: longint;
    dwInUcastPkts: longint;
    dwInNUcastPkts: longint;
    dwInDiscards: longint;
    dwInErrors: longint;
    dwInUnknownProtos: longint;
    dwOutOctets: longint;
    dwOutUcastPkts: longint;
    dwOutNUcastPkts: longint;
    dwOutDiscards: longint;
    dwOutErrors: longint;
    dwOutQLen:  longint;
    dwDescrLen: longint;
    bDescr:     array[0 .. (MAXLEN_IFDESCR - 1)] of ansichar;
  end;

type
  MIB_IPADDRROW = record
    dwAddr:      longint;
    dwIndex:     longint;
    dwMask:      longint;
    dwBCastAddr: longint;
    dwReasmSize: longint;
    unused1:     word;
    unused2:     word;
  end;

type
  _IfTable = record
    nRows: longint;
    ifRow: array[1.._MAX_ROWS_] of MIB_IFROW;
  end;

type
  _IpAddrTable = record
    dwNumEntries: longint;
    table: array[1..ANY_SIZE] of MIB_IPADDRROW;
  end;



function GetIfTable(pIfTable: Pointer; var pdwSize: longint; bOrder: longint): longint;
  stdcall;
function GetIpAddrTable(pIpAddrTable: Pointer; var pdwSize: longint;
  bOrder: longint): longint; stdcall;

function Get_if_type(iType: integer): string;
function Get_if_admin_status(iStatus: integer): string;
function Get_if_oper_status(iStatus: integer): string;


implementation

function GetIfTable; stdcall; external 'IPHLPAPI.DLL';
function GetIpAddrTable; stdcall; external 'IPHLPAPI.DLL';

function Get_if_type(iType: integer): string;
var
  sResult: string;
begin
  sResult := 'UNKNOWN';
  case iType of
    1: sResult   := 'Other';
    6: sResult   := 'Ethernet';
    9: sResult   := 'Tokenring';
    15: sResult  := 'FDDI';
    23: sResult  := 'PPP';
    24: sResult  := 'Local loopback';
    28: sResult  := 'SLIP';
    37: sResult  := 'ATM';
    71: sResult  := 'IEEE 802.11';
    131: sResult := 'Tunnel';
    144: sResult := 'IEEE 1394 (Firewire)';
  end;

  Result := sResult;
end;

function Get_if_admin_status(iStatus: integer): string;
var
  sResult: string;
begin
  sResult := 'UNKNOWN';

  case iStatus of
    1: sResult := 'UP';
    2: sResult := 'DOWN';
    3: sResult := 'TESTING';
  end;

  Result := sResult;
end;

function Get_if_oper_status(iStatus: integer): string;
var
  sResult: string;
begin
  sResult := 'UNKNOWN';

  case iStatus of
    0: sResult := 'NON_OPERATIONAL';
    1: sResult := 'UNREACHABLE';
    2: sResult := 'DISCONNECTED';
    3: sResult := 'CONNECTING';
    4: sResult := 'CONNECTED';
    5: sResult := 'OPERATIONAL';
  end;

  Result := sResult;
end;

end.

为了从另一个单元使用这个单元，我创建了以下函数，它填充了一个名为TAdapterInfo（在我的主单元中声明）的自定义类型：

type
  TAdapterInfo = array of record
    dwIndex:    longint;
    dwType:     longint;
    dwMtu:      longint;
    dwSpeed:    extended;
    dwPhysAddrLen: longint;
    bPhysAddr:  string;
    dwAdminStatus: longint;
    dwOperStatus: longint;
    dwLastChange: longint;
    dwInOctets: longint;
    dwInUcastPkts: longint;
    dwInNUcastPkts: longint;
    dwInDiscards: longint;
    dwInErrors: longint;
    dwInUnknownProtos: longint;
    dwOutOctets: longint;
    dwOutUcastPkts: longint;
    dwOutNUcastPkts: longint;
    dwOutDiscards: longint;
    dwOutErrors: longint;
    dwOutQLen:  longint;
    dwDescrLen: longint;
    bDescr:     string;
    sIpAddress: string;
    sIpMask:    string;
  end;

//////////

function Get_EthernetAdapterDetail(var AdapterDataFound: TAdapterInfo): boolean;
var
  pIfTable: ^_IfTable;
  pIpTable: ^_IpAddrTable;
  ifTableSize, ipTableSize: longint;
  tmp:      string;
  i, j, k, m: integer;
  ErrCode:  longint;
  sAddr, sMask: in_addr;
  IPAddresses, IPMasks: TStringList;
  sIPAddressLine, sIPMaskLine: string;
  bResult:  boolean;
begin
  bResult  := True; //default return value
  pIfTable := nil;
  pIpTable := nil;

  IPAddresses := TStringList.Create;
  IPMasks     := TStringList.Create;

  try
    // First: just get the buffer size.
    // TableSize returns the size needed.
    ifTableSize := 0; // Set to zero so the GetIfTabel function
    // won't try to fill the buffer yet,
    // but only return the actual size it needs.
    GetIfTable(pIfTable, ifTableSize, 1);
    if (ifTableSize < SizeOf(MIB_IFROW) + Sizeof(longint)) then
    begin
      bResult := False;
      Result  := bResult;
      Exit; // less than 1 table entry?!
    end;

    ipTableSize := 0;
    GetIpAddrTable(pIpTable, ipTableSize, 1);
    if (ipTableSize < SizeOf(MIB_IPADDRROW) + Sizeof(longint)) then
    begin
      bResult := False;
      Result  := bResult;
      Exit; // less than 1 table entry?!
    end;

    // Second:
    // allocate memory for the buffer and retrieve the
    // entire table.
    GetMem(pIfTable, ifTableSize);
    ErrCode := GetIfTable(pIfTable, ifTableSize, 1);

    if ErrCode <> ERROR_SUCCESS then
    begin
      bResult := False;
      Result  := bResult;
      Exit; // OK, that did not work. 
      // Not enough memory i guess.
    end;

    GetMem(pIpTable, ipTableSize);
    ErrCode := GetIpAddrTable(pIpTable, ipTableSize, 1);

    if ErrCode <> ERROR_SUCCESS then
    begin
      bResult := False;
      Result  := bResult;
      Exit;
    end;

    for k := 1 to pIpTable^.dwNumEntries do
    begin
      sAddr.S_addr := pIpTable^.table[k].dwAddr;
      sMask.S_addr := pIpTable^.table[k].dwMask;

      sIPAddressLine := Format('0x%8.8x', [(pIpTable^.table[k].dwIndex)]) +
        '=' + Format('%s', [inet_ntoa(sAddr)]);
      sIPMaskLine    := Format('0x%8.8x', [(pIpTable^.table[k].dwIndex)]) +
        '=' + Format('%s', [inet_ntoa(sMask)]);

      IPAddresses.Add(sIPAddressLine);
      IPMasks.Add(sIPMaskLine);
    end;

    SetLength(AdapterDataFound, pIfTable^.nRows); //initialize the array or records
    for i := 1 to pIfTable^.nRows do
      try
        //if pIfTable^.ifRow[i].dwType=MIB_IF_TYPE_ETHERNET then
        //begin
        m := i - 1;
        AdapterDataFound[m].dwIndex := 4;//(pIfTable^.ifRow[i].dwIndex);
        AdapterDataFound[m].dwType := (pIfTable^.ifRow[i].dwType);
        AdapterDataFound[m].dwIndex := (pIfTable^.ifRow[i].dwIndex);
        AdapterDataFound[m].sIpAddress :=
          IPAddresses.Values[Format('0x%8.8x', [(pIfTable^.ifRow[i].dwIndex)])];
        AdapterDataFound[m].sIpMask :=
          IPMasks.Values[Format('0x%8.8x', [(pIfTable^.ifRow[i].dwIndex)])];
        AdapterDataFound[m].dwMtu := (pIfTable^.ifRow[i].dwMtu);
        AdapterDataFound[m].dwSpeed := (pIfTable^.ifRow[i].dwSpeed);
        AdapterDataFound[m].dwAdminStatus := (pIfTable^.ifRow[i].dwAdminStatus);
        AdapterDataFound[m].dwOperStatus := (pIfTable^.ifRow[i].dwOperStatus);
        AdapterDataFound[m].dwInUcastPkts := (pIfTable^.ifRow[i].dwInUcastPkts);
        AdapterDataFound[m].dwInNUcastPkts := (pIfTable^.ifRow[i].dwInNUcastPkts);
        AdapterDataFound[m].dwInDiscards := (pIfTable^.ifRow[i].dwInDiscards);
        AdapterDataFound[m].dwInErrors := (pIfTable^.ifRow[i].dwInErrors);
        AdapterDataFound[m].dwInUnknownProtos := (pIfTable^.ifRow[i].dwInUnknownProtos);
        AdapterDataFound[m].dwOutNUcastPkts := (pIfTable^.ifRow[i].dwOutNUcastPkts);
        AdapterDataFound[m].dwOutUcastPkts := (pIfTable^.ifRow[i].dwOutUcastPkts);
        AdapterDataFound[m].dwOutDiscards := (pIfTable^.ifRow[i].dwOutDiscards);
        AdapterDataFound[m].dwOutErrors := (pIfTable^.ifRow[i].dwOutErrors);
        AdapterDataFound[m].dwOutQLen := (pIfTable^.ifRow[i].dwOutQLen);
        AdapterDataFound[m].bDescr := (pIfTable^.ifRow[i].bDescr);

        tmp := '';
        for j := 0 to pIfTable^.ifRow[i].dwPhysAddrLen - 1 do
        begin
          if Length(tmp) > 0 then
            tmp := tmp + '-' + format('%.2x', [pIfTable^.ifRow[i].bPhysAddr[j]])
          else
            tmp := tmp + format('%.2x', [pIfTable^.ifRow[i].bPhysAddr[j]]);
        end;

        if Length(tmp) > 0 then
        begin
          AdapterDataFound[m].bPhysAddr := tmp;
        end;
      except
        bResult := False;
        Result  := bResult;
        Exit;
      end;
  finally
    if Assigned(pIfTable) then
    begin
      FreeMem(pIfTable, ifTableSize);
    end;

    FreeAndNil(IPMasks);
    FreeAndNil(IPAddresses);
  end;

  Result := bResult;
end;

顺便说一句，我还使用这个单元和几乎完全相同的代码来创建 的副本ifconfig -a，可以在 github 上找到。我主要是作为一个练习来教自己如何完成这项任务。

Answer 2

uses WinInet;

function IsConnected: boolean;
const
  // local system uses a modem to connect to the Internet.
  INTERNET_CONNECTION_MODEM      = 1;
  // local system uses a local area network to connect to the Internet.
  INTERNET_CONNECTION_LAN        = 2;
  // local system uses a proxy server to connect to the Internet.
  INTERNET_CONNECTION_PROXY      = 4;
  // local system's modem is busy with a non-Internet connection.
  INTERNET_CONNECTION_MODEM_BUSY = 8;

var
  dwConnectionTypes : DWORD;
begin
  dwConnectionTypes := INTERNET_CONNECTION_MODEM +
                       INTERNET_CONNECTION_LAN +
                       INTERNET_CONNECTION_PROXY;
  Result := InternetGetConnectedState(@dwConnectionTypes,0);
end;

Answer 3

查看 WinINet 中的 InternetGetConnectedState。

一些应用程序还可能轮询已知服务器，并且在获得有效连接之前不执行任何操作。

Answer 4

这是一个如何使用辅助单元的工作示例。它来自我为模拟“ifconfig -a”而编写的一个小项目。这是一个控制台应用程序项目。

program ifconfig;

{$APPTYPE CONSOLE}

uses
  SysUtils,
  Classes,
  Winsock,
  uAdapterInfo in 'uAdapterInfo.pas';

type
  TAdapterInfo = array of record
    dwIndex:    longint;
    dwType:     longint;
    dwMtu:      longint;
    dwSpeed:    extended;
    dwPhysAddrLen: longint;
    bPhysAddr:  string;
    dwAdminStatus: longint;
    dwOperStatus: longint;
    dwLastChange: longint;
    dwInOctets: longint;
    dwInUcastPkts: longint;
    dwInNUcastPkts: longint;
    dwInDiscards: longint;
    dwInErrors: longint;
    dwInUnknownProtos: longint;
    dwOutOctets: longint;
    dwOutUcastPkts: longint;
    dwOutNUcastPkts: longint;
    dwOutDiscards: longint;
    dwOutErrors: longint;
    dwOutQLen:  longint;
    dwDescrLen: longint;
    bDescr:     string;
    sIpAddress: string;
    sIpMask:    string;
  end;




  function Get_EthernetAdapterDetail(var AdapterDataFound: TAdapterInfo): boolean;
  var
    pIfTable: ^_IfTable;
    pIpTable: ^_IpAddrTable;
    ifTableSize, ipTableSize: longint;
    tmp:      string;
    i, j, k, m: integer;
    ErrCode:  longint;
    sAddr, sMask: in_addr;
    IPAddresses, IPMasks: TStringList;
    sIPAddressLine, sIPMaskLine: string;
    bResult:  boolean;
  begin
    bResult  := True; //default return value
    pIfTable := nil;
    pIpTable := nil;

    IPAddresses := TStringList.Create;
    IPMasks     := TStringList.Create;

    try
      // First: just get the buffer size.
      // TableSize returns the size needed.
      ifTableSize := 0; // Set to zero so the GetIfTabel function
      // won't try to fill the buffer yet, 
      // but only return the actual size it needs.
      GetIfTable(pIfTable, ifTableSize, 1);
      if (ifTableSize < SizeOf(MIB_IFROW) + Sizeof(longint)) then
      begin
        bResult := False;
        Result := bResult;
        Exit; // less than 1 table entry?!
      end;

      ipTableSize := 0;
      GetIpAddrTable(pIpTable, ipTableSize, 1);
      if (ipTableSize < SizeOf(MIB_IPADDRROW) + Sizeof(longint)) then
      begin
        bResult := False;
        Result := bResult;
        Exit; // less than 1 table entry?!
      end;

      // Second:
      // allocate memory for the buffer and retrieve the 
      // entire table.
      GetMem(pIfTable, ifTableSize);
      ErrCode := GetIfTable(pIfTable, ifTableSize, 1);

      if ErrCode <> ERROR_SUCCESS then
      begin
        bResult := False;
        Result := bResult;
        Exit; // OK, that did not work. 
        // Not enough memory i guess.
      end;

      GetMem(pIpTable, ipTableSize);
      ErrCode := GetIpAddrTable(pIpTable, ipTableSize, 1);

      if ErrCode <> ERROR_SUCCESS then
      begin
        bResult := False;
        Result := bResult;
        Exit;
      end;

      for k := 1 to pIpTable^.dwNumEntries do
      begin
        sAddr.S_addr := pIpTable^.table[k].dwAddr;
        sMask.S_addr := pIpTable^.table[k].dwMask;

        sIPAddressLine := Format('0x%8.8x', [(pIpTable^.table[k].dwIndex)]) +
          '=' + Format('%s', [inet_ntoa(sAddr)]);
        sIPMaskLine    := Format('0x%8.8x', [(pIpTable^.table[k].dwIndex)]) +
          '=' + Format('%s', [inet_ntoa(sMask)]);

        IPAddresses.Add(sIPAddressLine);
        IPMasks.Add(sIPMaskLine);
      end;

      SetLength(AdapterDataFound, pIfTable^.nRows); //initialize the array or records
      for i := 1 to pIfTable^.nRows do
        try
          //if pIfTable^.ifRow[i].dwType=MIB_IF_TYPE_ETHERNET then
          //begin
          m := i - 1;
          AdapterDataFound[m].dwIndex := 4;//(pIfTable^.ifRow[i].dwIndex);
          AdapterDataFound[m].dwType := (pIfTable^.ifRow[i].dwType);
          AdapterDataFound[m].dwIndex := (pIfTable^.ifRow[i].dwIndex);
          AdapterDataFound[m].sIpAddress :=
            IPAddresses.Values[Format('0x%8.8x', [(pIfTable^.ifRow[i].dwIndex)])];
          AdapterDataFound[m].sIpMask :=
            IPMasks.Values[Format('0x%8.8x', [(pIfTable^.ifRow[i].dwIndex)])];
          AdapterDataFound[m].dwMtu := (pIfTable^.ifRow[i].dwMtu);
          AdapterDataFound[m].dwSpeed := (pIfTable^.ifRow[i].dwSpeed);
          AdapterDataFound[m].dwAdminStatus := (pIfTable^.ifRow[i].dwAdminStatus);
          AdapterDataFound[m].dwOperStatus := (pIfTable^.ifRow[i].dwOperStatus);
          AdapterDataFound[m].dwInUcastPkts := (pIfTable^.ifRow[i].dwInUcastPkts);
          AdapterDataFound[m].dwInNUcastPkts := (pIfTable^.ifRow[i].dwInNUcastPkts);
          AdapterDataFound[m].dwInDiscards := (pIfTable^.ifRow[i].dwInDiscards);
          AdapterDataFound[m].dwInErrors := (pIfTable^.ifRow[i].dwInErrors);
          AdapterDataFound[m].dwInUnknownProtos := (pIfTable^.ifRow[i].dwInUnknownProtos);
          AdapterDataFound[m].dwOutNUcastPkts := (pIfTable^.ifRow[i].dwOutNUcastPkts);
          AdapterDataFound[m].dwOutUcastPkts := (pIfTable^.ifRow[i].dwOutUcastPkts);
          AdapterDataFound[m].dwOutDiscards := (pIfTable^.ifRow[i].dwOutDiscards);
          AdapterDataFound[m].dwOutErrors := (pIfTable^.ifRow[i].dwOutErrors);
          AdapterDataFound[m].dwOutQLen := (pIfTable^.ifRow[i].dwOutQLen);
          AdapterDataFound[m].bDescr := (pIfTable^.ifRow[i].bDescr);

          tmp := '';
          for j := 0 to pIfTable^.ifRow[i].dwPhysAddrLen - 1 do
          begin
            if Length(tmp) > 0 then
              tmp := tmp + '-' + format('%.2x', [pIfTable^.ifRow[i].bPhysAddr[j]])
            else
              tmp := tmp + format('%.2x', [pIfTable^.ifRow[i].bPhysAddr[j]]);
          end;

          if Length(tmp) > 0 then
          begin
            AdapterDataFound[m].bPhysAddr := tmp;
          end;
        except
          bResult := False;
          Result := bResult;
          Exit;
        end;
    finally
      if Assigned(pIfTable) then
      begin
        FreeMem(pIfTable, ifTableSize);
      end;

      FreeAndNil(IPMasks);
      FreeAndNil(IPAddresses);
    end;

    Result := bResult;
  end;



var
  AdapterData: TAdapterInfo;
  i: integer;
begin
  try
    WriteLn('');
    if Get_EthernetAdapterDetail(AdapterData) then
    begin
      for i := 0 to Length(AdapterData) - 1 do
      begin
        WriteLn(Format('0x%8.8x', [AdapterData[i].dwIndex]));
        WriteLn('"' + AdapterData[i].bDescr + '"');
        Write(Format(#9 + 'Link encap: %s ', [Get_if_type(AdapterData[i].dwType)]));

        if Length(AdapterData[i].bPhysAddr) > 0 then
          Write('HWaddr: ' + AdapterData[i].bPhysAddr);

        Write(#13 + #10 + #9 + 'inet addr:' + AdapterData[i].sIpAddress);
        WriteLn(' Mask: ' + AdapterData[i].sIpMask);
        WriteLn(Format(#9 + 'MTU: %d Speed:%.2f Mbps', [AdapterData[i].dwMtu,
          (AdapterData[i].dwSpeed) / 1000 / 1000]));
        Write(#9 + 'Admin status:' + Get_if_admin_status(AdapterData[i].dwAdminStatus));
        WriteLn(' Oper status:' + Get_if_oper_status(AdapterData[i].dwOperStatus));
        WriteLn(#9 + Format('RX packets:%d dropped:%d errors:%d unkown:%d',
          [AdapterData[i].dwInUcastPkts + AdapterData[i].dwInNUcastPkts,
          AdapterData[i].dwInDiscards, AdapterData[i].dwInErrors,
          AdapterData[i].dwInUnknownProtos]));
        WriteLn(#9 + Format('TX packets:%d dropped:%d errors:%d txqueuelen:%d',
          [AdapterData[i].dwOutUcastPkts + AdapterData[i].dwOutNUcastPkts,
          AdapterData[i].dwOutDiscards, AdapterData[i].dwOutErrors,
          AdapterData[i].dwOutQLen]));

        WriteLn('');
      end;
    end
    else
    begin
      WriteLn(#13+#10+'*** Error retrieving adapter information');
    end;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.