Justin Rogers

TraceRoute Whidbey using System.Net.NetworkInformation...

Well, it appears that the new Whidbey Ping class is ultra-effective.  I've created a basic TraceRoute application making use of the API, that mimics most of the commands I have available on my XP based tracert.  I've tried to use as many neat features of the ping class as possible.  The basic algorithm is:

• Resolve the remote host if we need to
• Ping the remote host using TTL options so that we get the first intermediate host
• Ping the intermediate host to see how far away it is
• Repeat until we've reached our destination or the maximum allowed hops

I'm not even going to pretend the code is perfect, and some issues probably snuck in.  I coded this while checking out a bunch of editing features.  Gotta love full document formatting, and unlike with VS .NET 2003, this was actually fairly easy and quite robust.  Anyway, here goes TraceRoute .NET:

#region Using directives

using System;
using System.Collections.Generic;
using System.Text;

using System.Net;
using System.Net.NetworkInformation;

#endregion

namespace DWC.NetworkUtilities {
    class TraceRoute {
        private static string usageString = @"

Usage: TraceRoute [-d] [-h maximum_hops] [-j host-list] [-w timeout] target_name

Options:
    -d                 Do not resolve addresses to hostnames.
    -h maximum_hops    Maximum number of hops to search for target.
    -w timeout         Wait timeout milliseconds for each reply.
";
        static void Main( string[] args ) {
            if ( args.Length == 0 ) {
                Console.WriteLine( usageString );
                Environment.Exit( 1 );
            }
            string targetName = null;
            IPAddress target = IPAddress.None;
            bool resolveHostnames = true;
            int maxHops = 30;
            int timeout = 30000;
            int ttl = 1;
            Ping pinger = new Ping();
            bool finished = false;

            for ( int i = 0; i < args.Length; i++ ) {
                if ( args[i].StartsWith( "-" ) ) {
                    if ( args[i] == "-d" ) {
                        resolveHostnames = false;
                    } else if ( args[i] == "-h" && ( i + 1 ) < args.Length ) {
                        i++;
                        int.TryParse( args[i], out maxHops );
                    } else if ( args[i] == "-w" && ( i + 1 ) < args.Length ) {
                        i++;
                        int.TryParse( args[i], out timeout );
                    }
                } else {
                    try {
                        target = IPAddress.Parse( args[i] );
                    } catch {
                        try {
                            IPHostEntry hostEntry = Dns.GetHostByName( args[i] );
                            targetName = hostEntry.HostName;
                            target = hostEntry.AddressList[0];
                        } catch {
                            Console.WriteLine( usageString );
                            Environment.Exit( 2 );
                        }
                    }
                }
            }

            Console.WriteLine();
            Console.Write( "Tracing route to {0} ", ( targetName != null ) ? targetName : target.ToString() );
            if ( targetName != null ) { Console.Write( "[{0}] ", target.ToString() ); }
            Console.WriteLine( "over a maximum of {0} hops:", maxHops );
            Console.WriteLine();

            do {
                PingReply reply = pinger.Send( target, new byte[0], timeout, new PingOptions( ttl++, true ) );
                IPAddress replyAddress = reply.Address;
                if ( reply.Status == IPStatus.Success ) {
                    finished = true;
                }

                Console.Write( "{0, 3}", ttl - 1 );
                PingReply timing = pinger.Send( replyAddress, new byte[50], timeout, new PingOptions( 128, true ) );
                Console.Write( "{0, 5} ms", ( timing.Status == IPStatus.Success ) ? timing.RoundTripTime.ToString() : "*" );
                timing = pinger.Send( replyAddress, new byte[50], timeout, new PingOptions( 128, true ) );
                Console.Write( "{0, 5} ms", ( timing.Status == IPStatus.Success ) ? timing.RoundTripTime.ToString() : "*" );
                timing = pinger.Send( replyAddress, new byte[50], timeout, new PingOptions( 128, true ) );
                Console.Write( "{0, 5} ms", ( timing.Status == IPStatus.Success ) ? timing.RoundTripTime.ToString() : "*" );

                string hostName = null;
                if ( resolveHostnames ) {
                    try {
                        IPHostEntry hostEntry = Dns.GetHostByAddress( replyAddress );
                        if ( hostEntry.HostName != null && hostEntry.HostName != string.Empty ) {
                            hostName = hostEntry.HostName;
                        }
                    } catch { }
                }

                Console.WriteLine(
                    ( hostName != null ) ? "  {0} [{1}]" : "  {0}",
                    ( hostName != null ) ? hostName : replyAddress.ToString(),
                    replyAddress );
            } while ( !finished && ttl <= maxHops );

            Console.WriteLine();
            Console.WriteLine( "Trace complete, {0}", ( finished ) ? "destination reached" : "ttl expired reaching destination" );
        }
    }
}