How to get the local IP address using Inno Setup

Question

How can I get user\'s local IP address using Inno Setup?

I thought about using Win32 API GetIpAddrTable, but it is unclear how to make the adjustment. <

Answer 1

Build an external DLL that returns a list of IP addresses and read that list in Inno Setup script.

In this article you will find code example how to build a DLL and how to call it in the InnoSetup script.

In this SO post you will find how to get IP addresses using Indy library or plain WinApi.

Answer 2

It depends on if you want IPv4 address or the IPv6 address. But since you mentioned GetIpAddrTable and it only returns IPv4 addresses, I suspect that is what you wanted.

Each machine can have more than one local IP address. So I return them as a TStringList.
The machine I tested the following on had 5 IP addresses.

Since Inno Setup does not support pointers, I had to do everything through an Array of Byte for the buffer.

The code below is a complete Inno Setup script that demonstrates, how to use this function.

[Setup]
AppName=Test
AppVersion=1.5
DefaultDirName={pf}\test

[Code]

const
 ERROR_INSUFFICIENT_BUFFER = 122;


function GetIpAddrTable( pIpAddrTable: Array of Byte;
  var pdwSize: Cardinal; bOrder: WordBool ): DWORD;
external 'GetIpAddrTable@IpHlpApi.dll stdcall';


procedure GetIpAddresses(Addresses : TStringList);
var 
 Size : Cardinal;
 Buffer : Array of Byte;
 IpAddr : String;
 AddrCount : Integer;
 I, J : Integer;
begin
  { Find Size }
  if GetIpAddrTable(Buffer,Size,False) = ERROR_INSUFFICIENT_BUFFER then
  begin
     { Allocate Buffer with large enough size }
     SetLength(Buffer,Size);
     { Get List of IP Addresses into Buffer }
     if GetIpAddrTable(Buffer,Size,True) = 0 then
     begin
       { Find out how many addresses will be returned. }
       AddrCount := (Buffer[1] * 256) + Buffer[0];
       { Loop through addresses. }
       For I := 0 to AddrCount - 1 do
       begin
         IpAddr := '';
         { Loop through each byte of the address }
         For J := 0 to 3 do
         begin
           if J > 0 then
             IpAddr := IpAddr + '.';
           { Navigate through record structure to find correct byte of Addr }
           IpAddr := IpAddr + IntToStr(Buffer[I*24+J+4]);
         end;
         Addresses.Add(IpAddr);
       end;
     end;
  end;
end;

function InitializeSetup(): Boolean;
var
 SL : TStringList;
begin
  SL := TStringList.Create;
  GetIpAddresses(SL);
  MsgBox(SL.Text, mbInformation, MB_OK);
  SL.Free;
end;