Here is code to get arp table
public class GetArpTable
{
// The max number of physical addresses.
const int MAXLEN_PHYSADDR = 8;
// Define the MIB_IPNETROW structure.
struct MIB_IPNETROW
{
public int dwIndex;
public int dwPhysAddrLen;
public byte mac0;
public byte mac1;
public byte mac2;
public byte mac3;
public byte mac4;
public byte mac5;
public byte mac6;
public byte mac7;
public int dwAddr;
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 IntPtr buffer;
static int result;
public GetArpTable()
{
// The number of bytes needed.
int bytesNeeded = 0;
// The result from the API call.
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.
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);
}
}
finally
{
}
}
public static string ipstr;
public static string macname;
public static void GetNames(IP_Code.LocalHost LocalHost)
{
// 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& 0xFFFFFFFF));
Console.Write("IP:" + ip.ToString() + "\t\tMAC:");
ipstr = ip.ToString();
macname = "MAC:";
byte b;
b = table[index].mac0;
if (b < 0x10)
{
Console.Write("0");
macname = macname + "0";
}
else
{
Console.Write("");
}
Console.Write(b.ToString("X"));
macname = macname + b.ToString("X");
b = table[index].mac1;
if (b < 0x10)
{
Console.Write("-0");
macname = macname + "-0";
}
else
{
Console.Write("-");
macname = macname + "-";
}
Console.Write(b.ToString("X"));
macname = macname + b.ToString("X");
b = table[index].mac2;
if (b < 0x10)
{
Console.Write("-0");
macname = macname + "-0";
}
else
{
Console.Write("-");
macname = macname + "-";
}
Console.Write(b.ToString("X"));
macname = macname + b.ToString("X");
b = table[index].mac3;
if (b < 0x10)
{
Console.Write("-0");
macname = macname + "-0";
}
else
{
Console.Write("-");
macname = macname + "-";
}
Console.Write(b.ToString("X"));
macname = macname + b.ToString("X");
b = table[index].mac4;
if (b < 0x10)
{
Console.Write("-0");
macname = macname + "-0";
}
else
{
Console.Write("-");
macname = macname + "-";
}
Console.Write(b.ToString("X"));
macname = macname + b.ToString("X");
b = table[index].mac5;
if (b < 0x10)
{
Console.Write("-0");
macname = macname + "-0";
}
else
{
Console.Write("-");
macname = macname + "-";
}
Console.Write(b.ToString("X"));
macname = macname + b.ToString("X");
Console.WriteLine();
//test for device
if (table[index].mac0 == 0x00 &&
table[index].mac1 == 0x00 &&
table[index].mac2 == 0x00)
{
//if device matches
}
}
}
~GetArpTable()
{
// Release the memory.
Marshal.FreeCoTaskMem(buffer);
}
}
