private static void ListActive(CommandLineApplication command)
{
command.Description = "Lists the active hosts on the network by using arp-scan on the given interface.";
command.HelpOption("-?|-h|--help");
var interfaceNameArg = command.Argument("[interface]", "The name of the interface to use for scanning (e.g. eth0, ens192)");
var verboseOption = command.Option("-v|--verbose", "Verbose output.", CommandOptionType.NoValue);
command.OnExecute(() =>
{
var interfaceName = interfaceNameArg.Value;
if (String.IsNullOrEmpty(interfaceName))
{
PrintMissingArgumentError(interfaceNameArg.Name, _app, command.Name);
return(1);
}
var verbose = verboseOption.HasValue();
try
{
var output = ArpScan.Execute(interfaceName, verbose);
if (verbose)
{
Console.WriteLine("arp-scan output:{0}{1}", Environment.NewLine, output);
}
var aprScanEntries = Parser.ParseAprScanOutput(output);
Console.WriteLine("Hosts found via arp-scan:");
Console.WriteLine(" IP Address\tMAC Address\tManufacturer");
foreach (var aprScanEntry in aprScanEntries)
{
Console.WriteLine(" {0}\t{1}\t{2}", aprScanEntry.IpAddress, aprScanEntry.MacAddress, aprScanEntry.Manufacturer);
}
}
catch (Exception exception)
{
PrintUnhandledException(exception, verbose);
return(1);
}
if (verbose)
{
Console.WriteLine("Operation completed.");
}
return(0);
});
}
public static DetectUnknownHostsResults DetectUnknownHosts(
string interfaceName,
string hostsPath = "/etc/hosts",
string dhcpReservationsPath = null,
bool verbose = false)
{
// Sanity checking: ensure arguments are set as expected.
if (String.IsNullOrEmpty(interfaceName))
{
throw new ArgumentException("Interface name is required.");
}
if (String.IsNullOrEmpty(hostsPath))
{
throw new ArgumentException("Hosts path is required.");
}
if (!File.Exists(hostsPath))
{
throw new ArgumentException($"Could not locate hosts file with given path: {hostsPath}");
}
if (dhcpReservationsPath != null && !File.Exists(dhcpReservationsPath))
{
throw new ArgumentException($"Could not locate dnsmasq DHCP reservations file with given path: {dhcpReservationsPath}");
}
// Attempt to parse the hosts file.
if (verbose)
{
Console.WriteLine($"Parsing hosts file: {hostsPath}");
}
var hostEntries = Parser.ParseHostsFile(hostsPath);
if (verbose)
{
Console.WriteLine($"Parsed {hostEntries.Count} host entries.");
}
// Attempt to parse the dnsmasq DHCP reservations file.
if (verbose)
{
Console.WriteLine($"Parsing dnsmasq DHCP reservations file: {dhcpReservationsPath}");
}
List <DhcpReservationEntry> dhcpReservationEntries = null;
if (!String.IsNullOrEmpty(dhcpReservationsPath))
{
dhcpReservationEntries = Parser.ParseDhcpReservationsFile(dhcpReservationsPath);
if (verbose)
{
Console.WriteLine($"Parsed {dhcpReservationEntries.Count} DHCP reservation entries.");
}
}
// Delegate to arp-scan to scan the network for all hosts.
if (verbose)
{
Console.WriteLine($"Executing arp-scan on interface {interfaceName}");
}
var arpScanOutput = ArpScan.Execute(interfaceName, verbose);
var arpScanEntries = Parser.ParseAprScanOutput(arpScanOutput);
if (verbose)
{
Console.WriteLine($"Received {arpScanEntries.Count} arp-scan entries.");
}
// See if each IP address exists in known hosts or MAC address in known DHCP reservations.
var unknownHosts = new List <ArpScanEntry>();
List <KeyValuePair <ArpScanEntry, DhcpReservationEntry> > mismatchedIpAddressDhcpHosts = null;
foreach (var arpEntry in arpScanEntries)
{
var matchingHostsEntry = hostEntries.Find(x => x.IpAddress == arpEntry.IpAddress);
// Found a matching hosts entry.
if (matchingHostsEntry != null)
{
continue;
}
if (dhcpReservationEntries != null)
{
mismatchedIpAddressDhcpHosts = new List <KeyValuePair <ArpScanEntry, DhcpReservationEntry> >();
var matchingDhcpEntry = dhcpReservationEntries.Find(x => x.MacAddress == arpEntry.MacAddress);
// Found a DHCP reservation match by MAC address, make sure the IP address matches.
if (matchingDhcpEntry != null)
{
// Found a matching DHCP reservation entry.
if (matchingDhcpEntry.IpAddress == arpEntry.IpAddress)
{
continue;
}
// If the IP address doesn't match, something might be up.
mismatchedIpAddressDhcpHosts.Add(new KeyValuePair <ArpScanEntry, DhcpReservationEntry>(arpEntry, matchingDhcpEntry));
}
}
// Didn't find a match in either.
unknownHosts.Add(arpEntry);
}
return(new DetectUnknownHostsResults()
{
UnknownHosts = unknownHosts,
MismatchedIpAddressDhcpHosts = mismatchedIpAddressDhcpHosts,
});
}