Question

I’ve been using a 3G wireless card for a while and every time I connect, my anti-virus fires up the updates.

I’m wondering what is the Win32 API set of functions that I can use to, either, get notified or query about the event of an Internet Connection coming up?

And is there already a set of ported headers for Delphi?

Answer 1

I worked on a project to run a user’s logon script whenever they connected our network over VPN. To do this, I wrote a helper unit that retrieves adapter info and stores it into a simple record.

I then setup up a registry notification, see here for how to do that in Delphi

The registry notification was on HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces. This notification event fires every time Windows obtains a new IP address, or makes any type of change to an adapters connection information. When this event fired, I called the function (in the code below) to retrieve updated information about the adapter. I compared this new information to my previously recorded information…meaning I had to save the previous adapter info query in order to know if something had changed.

Anyhow, here is my helper unit:

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. 

To use this unit from another unit, I created the following function, which populated a custom type called TAdapterInfo (declared in my main unit):

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; 

On a completely side note, I also used this unit and almost exact same code to create a duplicate of ifconfig -a, which can be found on github. I mainly did it as an exercise in teaching myself how to accomplish this task.