Network infrastructure discovery - delphi

Question

I would like to perform a thorough LAN devices discovery, so that I can create a diagram similar to the one attached, but with additional information like IP and MAC addresses.
I've tried the code from Torry:
type
PNetResourceArray = ^TNetResourceArray;
TNetResourceArray = array[0..100] of TNetResource;
function CreateNetResourceList(ResourceType: DWord;
NetResource: PNetResource;
out Entries: DWord;
out List: PNetResourceArray): Boolean;
var
EnumHandle: THandle;
BufSize: DWord;
Res: DWord;
begin
Result := False;
List := Nil;
Entries := 0;
if WNetOpenEnum(RESOURCE_GLOBALNET,
ResourceType,
0,
NetResource,
EnumHandle) = NO_ERROR then begin
try
BufSize := $4000; // 16 kByte
GetMem(List, BufSize);
try
repeat
Entries := DWord(-1);
FillChar(List^, BufSize, 0);
Res := WNetEnumResource(EnumHandle, Entries, List, BufSize);
if Res = ERROR_MORE_DATA then
begin
ReAllocMem(List, BufSize);
end;
until Res <> ERROR_MORE_DATA;
Result := Res = NO_ERROR;
if not Result then
begin
FreeMem(List);
List := Nil;
Entries := 0;
end;
except
FreeMem(List);
raise;
end;
finally
WNetCloseEnum(EnumHandle);
end;
end;
end;
procedure ScanNetworkResources(ResourceType, DisplayType: DWord; List: TStrings);
procedure ScanLevel(NetResource: PNetResource);
var
Entries: DWord;
NetResourceList: PNetResourceArray;
i: Integer;
begin
if CreateNetResourceList(ResourceType, NetResource, Entries, NetResourceList) then try
for i := 0 to Integer(Entries) - 1 do
begin
if (DisplayType = RESOURCEDISPLAYTYPE_GENERIC) or
(NetResourceList[i].dwDisplayType = DisplayType) then begin
List.AddObject(NetResourceList[i].lpRemoteName,
Pointer(NetResourceList[i].dwDisplayType));
end;
if (NetResourceList[i].dwUsage and RESOURCEUSAGE_CONTAINER) <> 0 then
ScanLevel(#NetResourceList[i]);
end;
finally
FreeMem(NetResourceList);
end;
end;
begin
ScanLevel(Nil);
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
ScanNetworkResources(RESOURCETYPE_DISK, RESOURCEDISPLAYTYPE_SERVER, ListBox1.Items);
end;
But it only returns the names of the computers in the network, without the router and their IP address. So that's not really a solution.
Could you please tell me what is a good way to enumerate all devices (routers, computers, printers) in a local network, along with their IP and MAC addresses?
Thank you.

Answer 1

I modified you code adding the function GetHostName and inet_ntoa to get the ip address and the SendARP function to get the MAC address of a network resource.
{$APPTYPE CONSOLE}
{$R *.res}
uses
StrUtils,
Windows,
WinSock,
SysUtils;
type
PNetResourceArray = ^TNetResourceArray;
TNetResourceArray = array[0..1023] of TNetResource;
function SendArp(DestIP,SrcIP:ULONG;pMacAddr:pointer;PhyAddrLen:pointer) : DWord; StdCall; external 'iphlpapi.dll' name 'SendARP';
function GetIPAddress(const HostName: AnsiString): AnsiString;
var
HostEnt: PHostEnt;
Host: AnsiString;
SockAddr: TSockAddrIn;
begin
Result := '';
Host := HostName;
if Host = '' then
begin
SetLength(Host, MAX_PATH);
GetHostName(PAnsiChar(Host), MAX_PATH);
end;
HostEnt := GetHostByName(PAnsiChar(Host));
if HostEnt <> nil then
begin
SockAddr.sin_addr.S_addr := Longint(PLongint(HostEnt^.h_addr_list^)^);
Result := inet_ntoa(SockAddr.sin_addr);
end;
end;
function GetMacAddr(const IPAddress: AnsiString; var ErrCode : DWORD): AnsiString;
var
MacAddr : Array[0..5] of Byte;
DestIP : ULONG;
PhyAddrLen : ULONG;
begin
Result :='';
ZeroMemory(#MacAddr,SizeOf(MacAddr));
DestIP :=inet_addr(PAnsiChar(IPAddress));
PhyAddrLen:=SizeOf(MacAddr);
ErrCode :=SendArp(DestIP,0,#MacAddr,#PhyAddrLen);
if ErrCode = S_OK then
Result:=AnsiString(Format('%2.2x-%2.2x-%2.2x-%2.2x-%2.2x-%2.2x',[MacAddr[0], MacAddr[1],MacAddr[2], MacAddr[3], MacAddr[4], MacAddr[5]]));
end;
function ParseRemoteName(Const lpRemoteName : string) : string;
begin
Result:=lpRemoteName;
if StartsStr('\\', lpRemoteName) and (Length(lpRemoteName)>2) and (LastDelimiter('\', lpRemoteName)>2) then
Result:=Copy(lpRemoteName, 3, PosEx('\', lpRemoteName,3)-3)
else
if StartsStr('\\', lpRemoteName) and (Length(lpRemoteName)>2) and (LastDelimiter('\', lpRemoteName)=2) then
Result:=Copy(lpRemoteName, 3, length(lpRemoteName));
end;
function CreateNetResourceList(ResourceType: DWord;
NetResource: PNetResource;
out Entries: DWord;
out List: PNetResourceArray): Boolean;
var
EnumHandle: THandle;
BufSize: DWord;
Res: DWord;
begin
Result := False;
List := Nil;
Entries := 0;
if WNetOpenEnum(RESOURCE_GLOBALNET, ResourceType, 0, NetResource, EnumHandle) = NO_ERROR then
begin
try
BufSize := $4000; // 16 kByte
GetMem(List, BufSize);
try
repeat
Entries := DWord(-1);
FillChar(List^, BufSize, 0);
Res := WNetEnumResource(EnumHandle, Entries, List, BufSize);
if Res = ERROR_MORE_DATA then
begin
ReAllocMem(List, BufSize);
end;
until Res <> ERROR_MORE_DATA;
Result := Res = NO_ERROR;
if not Result then
begin
FreeMem(List);
List := Nil;
Entries := 0;
end;
except
FreeMem(List);
raise;
end;
finally
WNetCloseEnum(EnumHandle);
end;
end;
end;
procedure ScanNetworkResources(ResourceType, DisplayType: DWord);
procedure ScanLevel(NetResource: PNetResource);
var
Entries: DWord;
NetResourceList: PNetResourceArray;
i: Integer;
IPAddress, MacAddress : AnsiString;
ErrCode : DWORD;
begin
if CreateNetResourceList(ResourceType, NetResource, Entries, NetResourceList) then try
for i := 0 to Integer(Entries) - 1 do
begin
if (DisplayType = RESOURCEDISPLAYTYPE_GENERIC) or
(NetResourceList[i].dwDisplayType = DisplayType) then
begin
IPAddress :=GetIPAddress(ParseRemoteName(AnsiString(NetResourceList[i].lpRemoteName)));
MacAddress :=GetMacAddr(IPAddress, ErrCode);
Writeln(Format('Remote Name %s Ip %s MAC %s',[NetResourceList[i].lpRemoteName, IPAddress, MacAddress]));
end;
if (NetResourceList[i].dwUsage and RESOURCEUSAGE_CONTAINER) <> 0 then
ScanLevel(#NetResourceList[i]);
end;
finally
FreeMem(NetResourceList);
end;
end;
begin
ScanLevel(Nil);
end;
var
WSAData: TWSAData;
begin
try
if WSAStartup($0101, WSAData)=0 then
try
ScanNetworkResources(RESOURCETYPE_ANY, RESOURCEDISPLAYTYPE_SERVER);
Writeln('Done');
finally
WSACleanup;
end;
except
on E:Exception do
Writeln(E.Classname, ': ', E.Message);
end;
Readln;
end.