If you know which devices are out there you can use the Ping Class. This will allow you to at least fill up the ARP table. You can always execute ARP -a and parse the output if you have to. Here is also a link that shows how to pinvoke to call GetIpNetTable. I have included examples below of Ping Class and how to access the ARP table using the GetIpNetTable.
This is an example for the Ping Class
using System;
using System.Net;
using System.Net.NetworkInformation;
using System.Text;
namespace Examples.System.Net.NetworkInformation.PingTest
{
public class PingExample
{
// args[0] can be an IPaddress or host name.
public static void Main (string[] args)
{
Ping pingSender = new Ping ();
PingOptions options = new PingOptions ();
// Use the default Ttl value which is 128,
// but change the fragmentation behavior.
options.DontFragment = true;
// Create a buffer of 32 bytes of data to be transmitted.
string data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
byte[] buffer = Encoding.ASCII.GetBytes (data);
int timeout = 120;
PingReply reply = pingSender.Send (args[0], timeout, buffer, options);
if (reply.Status == IPStatus.Success)
{
Console.WriteLine ("Address: {0}", reply.Address.ToString ());
Console.WriteLine ("RoundTrip time: {0}", reply.RoundtripTime);
Console.WriteLine ("Time to live: {0}", reply.Options.Ttl);
Console.WriteLine ("Don't fragment: {0}", reply.Options.DontFragment);
Console.WriteLine ("Buffer size: {0}", reply.Buffer.Length);
}
}
}
}
This is an example of the GetIpNetTable.
using System;
using System.Runtime.InteropServices;
using System.ComponentModel;
using System.Net;
namespace GetIpNetTable
{
class Program
{
// The max number of physical addresses.
const int MAXLEN_PHYSADDR = 8;
// Define the MIB_IPNETROW structure.
[StructLayout(LayoutKind.Sequential)]
struct MIB_IPNETROW
{
[MarshalAs(UnmanagedType.U4)]
public int dwIndex;
[MarshalAs(UnmanagedType.U4)]
public int dwPhysAddrLen;
[MarshalAs(UnmanagedType.U1)]
public byte mac0;
[MarshalAs(UnmanagedType.U1)]
public byte mac1;
[MarshalAs(UnmanagedType.U1)]
public byte mac2;
[MarshalAs(UnmanagedType.U1)]
public byte mac3;
[MarshalAs(UnmanagedType.U1)]
public byte mac4;
[MarshalAs(UnmanagedType.U1)]
public byte mac5;
[MarshalAs(UnmanagedType.U1)]
public byte mac6;
[MarshalAs(UnmanagedType.U1)]
public byte mac7;
[MarshalAs(UnmanagedType.U4)]
public int dwAddr;
[MarshalAs(UnmanagedType.U4)]
public int dwType;
}
// Declare the GetIpNetTable function.
[DllImport("IpHlpApi.dll")]
[return: MarshalAs(UnmanagedType.U4)]
static extern int GetIpNetTable(
IntPtr pIpNetTable,
[MarshalAs(UnmanagedType.U4)]
ref int pdwSize,
bool bOrder);
// The insufficient buffer error.
const int ERROR_INSUFFICIENT_BUFFER = 122;
static void Main(string[] args)
{
// The number of bytes needed.
int bytesNeeded = 0;
// The result from the API call.
int result = GetIpNetTable(IntPtr.Zero, ref bytesNeeded, false);
// Call the function, expecting an insufficient buffer.
if (result != ERROR_INSUFFICIENT_BUFFER)
{
// Throw an exception.
throw new Win32Exception(result);
}
// Allocate the memory, do it in a try/finally block, to ensure
// that it is released.
IntPtr buffer = IntPtr.Zero;
// Try/finally.
try
{
// Allocate the memory.
buffer = Marshal.AllocCoTaskMem(bytesNeeded);
// Make the call again. If it did not succeed, then
// raise an error.
result = GetIpNetTable(buffer, ref bytesNeeded, false);
// If the result is not 0 (no error), then throw an exception.
if (result != 0)
{
// Throw an exception.
throw new Win32Exception(result);
}
// Now we have the buffer, we have to marshal it. We can read
// the first 4 bytes to get the length of the buffer.
int entries = Marshal.ReadInt32(buffer);
// Increment the memory pointer by the size of the int.
IntPtr currentBuffer = new IntPtr(buffer.ToInt64() +
Marshal.SizeOf(typeof(int)));
// Allocate an array of entries.
MIB_IPNETROW[] table = new MIB_IPNETROW[entries];
// Cycle through the entries.
for (int index = 0; index < entries; index++)
{
// Call PtrToStructure, getting the structure information.
table[index] = (MIB_IPNETROW) Marshal.PtrToStructure(new
IntPtr(currentBuffer.ToInt64() + (index *
Marshal.SizeOf(typeof(MIB_IPNETROW)))), typeof(MIB_IPNETROW));
}
for (int index = 0; index < entries; index++)
{
IPAddress ip=new IPAddress(table[index].dwAddr);
Console.Write("IP:"+ip.ToString()+"\t\tMAC:");
byte b;
b=table[index].mac0;
if ( b < 0x10)
{
Console.Write("0");
}
else
{
Console.Write("");
}
Console.Write(b.ToString("X"));
b=table[index].mac1;
if ( b < 0x10)
{
Console.Write("-0");
}
else
{
Console.Write("-");
}
Console.Write(b.ToString("X"));
b=table[index].mac2;
if ( b < 0x10)
{
Console.Write("-0");
}
else
{
Console.Write("-");
}
Console.Write(b.ToString("X"));
b=table[index].mac3;
if ( b < 0x10)
{
Console.Write("-0");
}
else
{
Console.Write("-");
}
Console.Write(b.ToString("X"));
b=table[index].mac4;
if ( b < 0x10)
{
Console.Write("-0");
}
else
{
Console.Write("-");
}
Console.Write(b.ToString("X"));
b=table[index].mac5;
if ( b < 0x10)
{
Console.Write("-0");
}
else
{
Console.Write("-");
}
Console.Write(b.ToString("X"));
Console.WriteLine();
}
}
finally
{
// Release the memory.
Marshal.FreeCoTaskMem(buffer);
}
}
}
}