private static void BuildIndexToInterfaceMap(NetworkInterface ni, SortedDictionary <uint, ArpTableDTO> adapters)
{
// We don't care about the loopback interface
// if (ni.NetworkInterfaceType == NetworkInterfaceType.Loopback) return;
var adapterProperties = ni.GetIPProperties();
if (adapterProperties == null)
{
throw new Exception("Could not get adapter IP properties");
}
var index = (uint?)ni.GetType().GetField("index", BindingFlags.NonPublic | BindingFlags.Instance)?.GetValue(ni);
if (index == null)
{
throw new Exception("Could not get interface index number");
}
Console.WriteLine(ni.Description);
var adapter = new ArpTableDTO(index.Value, ni.Name, ni.Description);
adapterProperties.UnicastAddresses
.ToList()
.ForEach(ip => adapter.InterfaceIPs.Add(ip.Address.ToString()));
adapterProperties.DnsAddresses
.ToList()
.ForEach(dns => adapter.DnsServers.Add(dns.ToString()));
adapters.Add(index.Value, adapter);
}
public override IEnumerable <CommandDTOBase?> Execute(string[] args)
{
// adapted from Fred's code at https://social.technet.microsoft.com/Forums/lync/en-US/e949b8d6-17ad-4afc-88cd-0019a3ac9df9/powershell-alternative-to-arp-a?forum=ITCG
var adapterIdToInterfaceMap = new SortedDictionary <uint, ArpTableDTO>();
// build a mapping of index -> interface information
foreach (var networkInterface in NetworkInterface.GetAllNetworkInterfaces())
{
BuildIndexToInterfaceMap(networkInterface, adapterIdToInterfaceMap);
}
var bytesNeeded = 0;
var result = Iphlpapi.GetIpNetTable(IntPtr.Zero, ref bytesNeeded, false);
if (result != Win32Error.InsufficientBuffer)
{
throw new Exception($"GetIpNetTable: Expected insufficient buffer but got {result}");
}
var buffer = Marshal.AllocCoTaskMem(bytesNeeded);
try
{
result = Iphlpapi.GetIpNetTable(buffer, ref bytesNeeded, false);
if (result != 0)
{
throw new Exception($"GetIpNetTable error: {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
var entries = Marshal.ReadInt32(buffer);
// increment the memory pointer by the size of the int
var currentBuffer = new IntPtr(buffer.ToInt64() + Marshal.SizeOf(typeof(int)));
// allocate a list of entries
var arpEntries = new List <Iphlpapi.MIB_IPNETROW>();
// cycle through the entries
for (var index = 0; index < entries; index++)
{
arpEntries.Add((Iphlpapi.MIB_IPNETROW)Marshal.PtrToStructure(
new IntPtr(currentBuffer.ToInt64() + (index * Marshal.SizeOf(typeof(Iphlpapi.MIB_IPNETROW)))),
typeof(Iphlpapi.MIB_IPNETROW)));
}
// sort the list by interface index
var sortedArpEntries = arpEntries.OrderBy(o => o.dwIndex).ToList();
uint?currentAdapterIndex = null;
foreach (var arpEntry in sortedArpEntries)
{
var adapterIndex = (uint)arpEntry.dwIndex;
if (currentAdapterIndex != adapterIndex)
{
if (!adapterIdToInterfaceMap.ContainsKey(adapterIndex))
{
adapterIdToInterfaceMap[adapterIndex] = new ArpTableDTO(adapterIndex, "n/a", "n/a");
}
currentAdapterIndex = adapterIndex;
}
var ipAddress = new IPAddress(BitConverter.GetBytes(arpEntry.dwAddr));
var macBytes = new[]
{ arpEntry.mac0, arpEntry.mac1, arpEntry.mac2, arpEntry.mac3, arpEntry.mac4, arpEntry.mac5 };
var physicalAddress = BitConverter.ToString(macBytes);
var entryType = (Iphlpapi.ArpEntryType)arpEntry.dwType;
var entry = new ArpEntry(
ipAddress.ToString(),
physicalAddress,
entryType.ToString()
);
adapterIdToInterfaceMap[adapterIndex].Entries.Add(entry);
}
}
finally
{
if (buffer != IntPtr.Zero)
{
Iphlpapi.FreeMibTable(buffer);
}
}
foreach (var adapter in adapterIdToInterfaceMap)
{
yield return(adapter.Value);
}
}
