Title: Getting the IP address and mask for ALL TCP/IP interfaces
Question: We have seen a lot of methods obtaining the IP address of a machine. This is the "correct" method listing all addresses, network masks, broadcast addresses and status for all interfaces, including the loopback 127.0.0.1 - Requires WinSock 2
Answer:
This is a complete Delphi unit. By adding it to a project you can
call :
EnumInterfaces(var s string): Boolean;
that returns a CRLF separated string of all IP addresses, netmasks,
broadcast addresses and interface status.
--------------------------------------------------------------------
unit USock;
interface
uses Windows, Winsock;
{
This function enumerates all TCP/IP interfaces and
returns a CRLF separated string containing:
IP, NetMask, BroadCast-Address, Up/Down status,
Broadcast support, Loopback
If you feed this string to a wide TMEMO (to its memo.lines.text
property) you will see cleary the results.
To use this you need Win98/ME/2K, 95 OSR 2 or NT service
pack #3 because WinSock 2 is used (WS2_32.DLL)
}
function EnumInterfaces(var sInt: string): Boolean;
{ Imported function WSAIOCtl from Winsock 2.0 - Winsock 2 is }
{ available only in Win98/ME/2K and 95 OSR2, NT srv pack #3 }
function WSAIoctl(s: TSocket; cmd: DWORD; lpInBuffer: PCHAR; dwInBufferLen:
DWORD;
lpOutBuffer: PCHAR; dwOutBufferLen: DWORD;
lpdwOutBytesReturned: LPDWORD;
lpOverLapped: POINTER;
lpOverLappedRoutine: POINTER): Integer; stdcall; external 'WS2_32.DLL';
{ Constants taken from C header files }
const SIO_GET_INTERFACE_LIST = $4004747F;
IFF_UP = $00000001;
IFF_BROADCAST = $00000002;
IFF_LOOPBACK = $00000004;
IFF_POINTTOPOINT = $00000008;
IFF_MULTICAST = $00000010;
type sockaddr_gen = packed record
AddressIn: sockaddr_in;
filler: packed array[0..7] of char;
end;
type INTERFACE_INFO = packed record
iiFlags: u_long; // Interface flags
iiAddress: sockaddr_gen; // Interface address
iiBroadcastAddress: sockaddr_gen; // Broadcast address
iiNetmask: sockaddr_gen; // Network mask
end;
implementation
{-------------------------------------------------------------------
1. Open WINSOCK
2. Create a socket
3. Call WSAIOCtl to obtain network interfaces
4. For every interface, get IP, MASK, BROADCAST, status
5. Fill a CRLF separated string with this info
6. Finito
--------------------------------------------------------------------}
function EnumInterfaces(var sInt: string): Boolean;
var s: TSocket;
wsaD: WSADATA;
NumInterfaces: Integer;
BytesReturned, SetFlags: u_long;
pAddrInet: SOCKADDR_IN;
pAddrString: PCHAR;
PtrA: pointer;
Buffer: array[0..20] of INTERFACE_INFO;
i: Integer;
begin
result := true; // Initialize
sInt := '';
WSAStartup($0101, wsaD); // Start WinSock
// You should normally check
// for errors here :)
s := Socket(AF_INET, SOCK_STREAM, 0); // Open a socket
if (s = INVALID_SOCKET) then exit;
try // Call WSAIoCtl
PtrA := @bytesReturned;
if (WSAIoCtl(s, SIO_GET_INTERFACE_LIST, nil, 0, @Buffer, 1024, PtrA, nil,
nil)
SOCKET_ERROR)
then
begin // If ok, find out how
// many interfaces exist
NumInterfaces := BytesReturned div SizeOf(INTERFACE_INFO);
for i := 0 to NumInterfaces - 1 do // For every interface
begin
pAddrInet := Buffer[i].iiAddress.addressIn; // IP ADDRESS
pAddrString := inet_ntoa(pAddrInet.sin_addr);
sInt := sInt + ' IP=' + pAddrString + ',';
pAddrInet := Buffer[i].iiNetMask.addressIn; // SUBNET MASK
pAddrString := inet_ntoa(pAddrInet.sin_addr);
sInt := sInt + ' Mask=' + pAddrString + ',';
pAddrInet := Buffer[i].iiBroadCastAddress.addressIn; // Broadcast addr
pAddrString := inet_ntoa(pAddrInet.sin_addr);
sInt := sInt + ' Broadcast=' + pAddrString + ',';
SetFlags := Buffer[i].iiFlags;
if (SetFlags and IFF_UP) = IFF_UP then
sInt := sInt + ' Interface UP,' // Interface up/down
else
sInt := sInt + ' Interface DOWN,';
if (SetFlags and IFF_BROADCAST) = IFF_BROADCAST then // Broadcasts
sInt := sInt + ' Broadcasts supported,' // supported or
else // not supported
sInt := sInt + ' Broadcasts NOT supported,';
if (SetFlags and IFF_LOOPBACK) = IFF_LOOPBACK then // Loopback or
sInt := sInt + ' Loopback interface'
else
sInt := sInt + ' Network interface'; // normal
sInt := sInt + #13#10; // CRLF between
// each interface
end;
end;
except
end;
//
// Close sockets
//
CloseSocket(s);
WSACleanUp;
result := false;
end;
end.