/*
C# Network Programming
by Richard Blum
Publisher: Sybex
ISBN: 0782141765
*/
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
public class TraceRoute
{
public static void Main(string[] argv)
{
byte[] data = new byte[1024];
int recv, timestart, timestop;
Socket host = new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp);
IPHostEntry iphe = Dns.Resolve(argv[0]);
IPEndPoint iep = new IPEndPoint(iphe.AddressList[0], 0);
EndPoint ep = (EndPoint)iep;
ICMP packet = new ICMP();
packet.Type = 0x08;
packet.Code = 0x00;
packet.Checksum = 0;
Buffer.BlockCopy(BitConverter.GetBytes(1), 0, packet.Message, 0, 2);
Buffer.BlockCopy(BitConverter.GetBytes(1), 0, packet.Message, 2, 2);
data = Encoding.ASCII.GetBytes("test packet");
Buffer.BlockCopy(data, 0, packet.Message, 4, data.Length);
packet.MessageSize = data.Length + 4;
int packetsize = packet.MessageSize + 4;
UInt16 chcksum = packet.getChecksum();
packet.Checksum = chcksum;
host.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 3000);
int badcount = 0;
for (int i = 1; i < 50; i++)
{
host.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.IpTimeToLive, i);
timestart = Environment.TickCount;
host.SendTo(packet.getBytes(), packetsize, SocketFlags.None, iep);
try
{
data = new byte[1024];
recv = host.ReceiveFrom(data, ref ep);
timestop = Environment.TickCount;
ICMP response = new ICMP(data, recv);
if (response.Type == 11)
Console.WriteLine("hop {0}: response from {1}, {2}ms", i, ep.ToString(), timestop-timestart);
if (response.Type == 0)
{
Console.WriteLine("{0} reached in {1} hops, {2}ms.", ep.ToString(), i, timestop-timestart);
break;
}
badcount = 0;
} catch (SocketException)
{
Console.WriteLine("hop {0}: No response from remote host", i);
badcount++;
if (badcount == 5)
{
Console.WriteLine("Unable to contact remote host");
break;
}
}
}
host.Close();
}
}
class ICMP
{
public byte Type;
public byte Code;
public UInt16 Checksum;
public int MessageSize;
public byte[] Message = new byte[1024];
public ICMP()
{
}
public ICMP(byte[] data, int size)
{
Type = data[20];
Code = data[21];
Checksum = BitConverter.ToUInt16(data, 22);
MessageSize = size - 24;
Buffer.BlockCopy(data, 24, Message, 0, MessageSize);
}
public byte[] getBytes()
{
byte[] data = new byte[MessageSize + 9];
Buffer.BlockCopy(BitConverter.GetBytes(Type), 0, data, 0, 1);
Buffer.BlockCopy(BitConverter.GetBytes(Code), 0, data, 1, 1);
Buffer.BlockCopy(BitConverter.GetBytes(Checksum), 0, data, 2, 2);
Buffer.BlockCopy(Message, 0, data, 4, MessageSize);
return data;
}
public UInt16 getChecksum()
{
UInt32 chcksm = 0;
byte[] data = getBytes();
int packetsize = MessageSize + 8;
int index = 0;
while ( index < packetsize)
{
chcksm += Convert.ToUInt32(BitConverter.ToUInt16(data, index));
index += 2;
}
chcksm = (chcksm >> 16) + (chcksm & 0xffff);
chcksm += (chcksm >> 16);
return (UInt16)(~chcksm);
}
}
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