Detecting Wifi Networks Using Delphi and Native Wifi API

October 7, 2009 by Rodrigo 25 Comments

Today we will use the Native Wifi API and Delphi to enumerate all Wifi Networks availables. In this link you can find a translation of the headers.
I wrote this code using these headers. Tested in Delphi 2007 and Windows Vista.

Try this link for a fixed and updated version of the Native Wifi Delphi headers.

{$APPTYPE CONSOLE}

uses
  Windows,
  SysUtils,
  nduWlanAPI   in 'nduWlanAPI.pas',
  nduWlanTypes in 'nduWlanTypes.pas';

function DOT11_AUTH_ALGORITHM_To_String( Dummy :Tndu_DOT11_AUTH_ALGORITHM):AnsiString;
begin
    Result:='';
    case Dummy of
        DOT11_AUTH_ALGO_80211_OPEN          : Result:= '80211_OPEN';
        DOT11_AUTH_ALGO_80211_SHARED_KEY    : Result:= '80211_SHARED_KEY';
        DOT11_AUTH_ALGO_WPA                 : Result:= 'WPA';
        DOT11_AUTH_ALGO_WPA_PSK             : Result:= 'WPA_PSK';
        DOT11_AUTH_ALGO_WPA_NONE            : Result:= 'WPA_NONE';
        DOT11_AUTH_ALGO_RSNA                : Result:= 'RSNA';
        DOT11_AUTH_ALGO_RSNA_PSK            : Result:= 'RSNA_PSK';
        DOT11_AUTH_ALGO_IHV_START           : Result:= 'IHV_START';
        DOT11_AUTH_ALGO_IHV_END             : Result:= 'IHV_END';
    end;
end;

function DOT11_CIPHER_ALGORITHM_To_String( Dummy :Tndu_DOT11_CIPHER_ALGORITHM):AnsiString;
begin
    Result:='';
    case Dummy of
  	DOT11_CIPHER_ALGO_NONE      : Result:= 'NONE';
    DOT11_CIPHER_ALGO_WEP40     : Result:= 'WEP40';
    DOT11_CIPHER_ALGO_TKIP      : Result:= 'TKIP';
    DOT11_CIPHER_ALGO_CCMP      : Result:= 'CCMP';
    DOT11_CIPHER_ALGO_WEP104    : Result:= 'WEP104';
    DOT11_CIPHER_ALGO_WPA_USE_GROUP : Result:= 'WPA_USE_GROUP OR RSN_USE_GROUP';
    //DOT11_CIPHER_ALGO_RSN_USE_GROUP : Result:= 'RSN_USE_GROUP';
    DOT11_CIPHER_ALGO_WEP           : Result:= 'WEP';
    DOT11_CIPHER_ALGO_IHV_START     : Result:= 'IHV_START';
    DOT11_CIPHER_ALGO_IHV_END       : Result:= 'IHV_END';
    end;
end;

procedure Scan();
const
WLAN_AVAILABLE_NETWORK_INCLUDE_ALL_ADHOC_PROFILES =$00000001;
var
  hClient              : THandle;
  dwVersion            : DWORD;
  ResultInt            : DWORD;
  pInterface           : Pndu_WLAN_INTERFACE_INFO_LIST;
  i                    : Integer;
  j                    : Integer;
  pAvailableNetworkList: Pndu_WLAN_AVAILABLE_NETWORK_LIST;
  pInterfaceGuid       : PGUID;
  SDummy               : AnsiString;
begin
  ResultInt:=WlanOpenHandle(1, nil, @dwVersion, @hClient);
   try
    if  ResultInt<> ERROR_SUCCESS then
    begin
       WriteLn('Error Open CLient'+IntToStr(ResultInt));
       Exit;
    end;

    ResultInt:=WlanEnumInterfaces(hClient, nil, @pInterface);
    if  ResultInt<> ERROR_SUCCESS then
    begin
       WriteLn('Error Enum Interfaces '+IntToStr(ResultInt));
       exit;
    end;

    for i := 0 to pInterface^.dwNumberOfItems - 1 do
    begin
     Writeln('Interface       ' + pInterface^.InterfaceInfo[i].strInterfaceDescription);
     WriteLn('GUID            ' + GUIDToString(pInterface^.InterfaceInfo[i].InterfaceGuid));
     Writeln('');
     pInterfaceGuid:= @pInterface^.InterfaceInfo[pInterface^.dwIndex].InterfaceGuid;

        ResultInt:=WlanGetAvailableNetworkList(hClient,pInterfaceGuid,WLAN_AVAILABLE_NETWORK_INCLUDE_ALL_ADHOC_PROFILES,nil,pAvailableNetworkList);
        if  ResultInt<> ERROR_SUCCESS then
        begin
           WriteLn('Error WlanGetAvailableNetworkList '+IntToStr(ResultInt));
           Exit;
        end;

          for j := 0 to pAvailableNetworkList^.dwNumberOfItems - 1 do
          Begin
             WriteLn(Format('Profile         %s',[WideCharToString(pAvailableNetworkList^.Network[j].strProfileName)]));
             SDummy:=PAnsiChar(@pAvailableNetworkList^.Network[j].dot11Ssid.ucSSID);
             WriteLn(Format('NetworkName     %s',[SDummy]));
             WriteLn(Format('Signal Quality  %d ',[pAvailableNetworkList^.Network[j].wlanSignalQuality])+'%');
             //SDummy := GetEnumName(TypeInfo(Tndu_DOT11_AUTH_ALGORITHM),integer(pAvailableNetworkList^.Network[j].dot11DefaultAuthAlgorithm)) ;
             SDummy:=DOT11_AUTH_ALGORITHM_To_String(pAvailableNetworkList^.Network[j].dot11DefaultAuthAlgorithm);
             WriteLn(Format('Auth Algorithm  %s ',[SDummy]));
             SDummy:=DOT11_CIPHER_ALGORITHM_To_String(pAvailableNetworkList^.Network[j].dot11DefaultCipherAlgorithm);
             WriteLn(Format('Auth Algorithm  %s ',[SDummy]));
             Writeln('');
          End;
    end;
   finally
    WlanCloseHandle(hClient, nil);
   end;
end;
begin
  try
    Scan();
    Readln;
  except
    on E:Exception do
      Writeln(E.Classname, ': ', E.Message);
  end;
end.

ScanWifi Image