class1.cs

Csharp实例编程百例.rar

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace TraceRoute
{
	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);
		}
	}
}