ping.cs

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using System;
using System.Net;
using System.Net.Sockets;
/// <summary>
///		The Main Ping Class
/// </summary>
class Ping
{
	// Declare some Constant Variables
    const int SOCKET_ERROR = -1;        
    const int ICMP_ECHO = 8;
	
	/// <summary>
	///		The Starting Point of the Class
	///		It Takes the Hostname parameter
	/// </summary>
	public static void Main(string[] argv)
	{
		if(argv.Length==0)
		{
			//If user did not enter any Parameter inform him
			Console.WriteLine("Usage:Ping <hostname> /r") ;
			Console.WriteLine("<hostname> The name of the Host who you want to ping");
			Console.WriteLine("/r Optional Switch to Ping the host continuously") ;
		}
		else if(argv.Length==1)
		{
			//Just the hostname provided by the user
			//call the method "PingHost" and pass the HostName as a parameter
			PingHost(argv[0]) ;
		}
		else if(argv.Length==2)
		{
			//the user provided the hostname and the switch
			if(argv[1]=="/r")
			{
				//loop the ping program
				while(true)
				{
					//call the method "PingHost" and pass the HostName as a parameter
					PingHost(argv[0]) ;
				}
			}
			else
			{
				//if the user provided some other switch
				PingHost(argv[0]) ;
			}
			
		}
		else
		{
			//Some error occured
			Console.WriteLine("Error in Arguments") ;
		}
	}
	
	/// <summary>
	///		This method takes the "hostname" of the server
	///		and then it ping's it and shows the response time
	/// </summary>
	public static void PingHost(string host)
	{
		//Declare the IPHostEntry 
        IPHostEntry serverHE, fromHE;
        int nBytes = 0;
        int dwStart = 0, dwStop = 0;
        //Initilize a Socket of the Type ICMP
        Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp);

        // Get the server endpoint
		try
		{
			serverHE = Dns.GetHostByName(host);	
		}
        catch(Exception)
		{
			Console.WriteLine("Host not found"); // fail
			return ;
		}

        // Convert the server IP_EndPoint to an EndPoint
        IPEndPoint ipepServer = new IPEndPoint(serverHE.AddressList[0], 0);
        EndPoint epServer = (ipepServer);	

		// Set the receiving endpoint to the client machine
        fromHE = Dns.GetHostByName(Dns.GetHostName());
        IPEndPoint ipEndPointFrom = new IPEndPoint(fromHE.AddressList[0], 0);        
        EndPoint EndPointFrom = (ipEndPointFrom);

        int PacketSize = 0;
		IcmpPacket packet = new IcmpPacket();
        // Construct the packet to send
        packet.Type = ICMP_ECHO; //8
        packet.SubCode = 0;
        packet.CheckSum = UInt16.Parse("0");
        packet.Identifier   = UInt16.Parse("45"); 
        packet.SequenceNumber  = UInt16.Parse("0"); 
		int PingData = 32; // sizeof(IcmpPacket) - 8;
        packet.Data = new Byte[PingData];
		//Initilize the Packet.Data
        for (int i = 0; i < PingData; i++)
		{
			packet.Data[i] = (byte)'#';
		}
             
		//Variable to hold the total Packet size
        PacketSize = PingData + 8;
        Byte [] icmp_pkt_buffer = new Byte[ PacketSize ]; 
        Int32 Index = 0;
		//Call a Methos Serialize which counts
		//The total number of Bytes in the Packet
        Index = Serialize(  
                      packet, 
                      icmp_pkt_buffer, 
                      PacketSize, 
                      PingData );
		//Error in Packet Size
        if( Index == -1 )
		{
			Console.WriteLine("Error in Making Packet");
			return ;
		}
      
            // now get this critter into a UInt16 array
         
            //Get the Half size of the Packet
            Double double_length = Convert.ToDouble(Index);
            Double dtemp = Math.Ceiling( double_length / 2);
			int cksum_buffer_length = Convert.ToInt32(dtemp);
            //Create a Byte Array
            UInt16 [] cksum_buffer = new UInt16[cksum_buffer_length];
			//Code to initilize the Uint16 array 
            int icmp_header_buffer_index = 0;
            for( int i = 0; i < cksum_buffer_length; i++ ) {
				cksum_buffer[i] = 
                   BitConverter.ToUInt16(icmp_pkt_buffer,icmp_header_buffer_index);
                icmp_header_buffer_index += 2;
            }
			//Call a method which will return a checksum             
            UInt16 u_cksum = checksum(cksum_buffer, cksum_buffer_length);
			//Save the checksum to the Packet
            packet.CheckSum  = u_cksum; 
            
            // Now that we have the checksum, serialize the packet again
            Byte [] sendbuf = new Byte[ PacketSize ]; 
            //again check the packet size
            Index = Serialize(  
                        packet, 
                        sendbuf, 
                        PacketSize, 
                        PingData );
			//if there is a error report it
            if( Index == -1 )
			{
				Console.WriteLine("Error in Making Packet");
				return ;
			}
                

            dwStart = System.Environment.TickCount; // Start timing
			//send the Pack over the socket
            if ((nBytes = socket.SendTo(sendbuf, PacketSize, 0, epServer)) == SOCKET_ERROR) 
			{		
                Console.WriteLine("Socket Error cannot Send Packet");
            }
			// Initialize the buffers. The receive buffer is the size of the
            // ICMP header plus the IP header (20 bytes)
            Byte [] ReceiveBuffer = new Byte[256]; 
            nBytes = 0;
			//Receive the bytes
            bool recd =false ;
			int timeout=0 ;

			//loop for checking the time of the server responding 
			while(!recd)
			{
				nBytes = socket.ReceiveFrom(ReceiveBuffer, 256, 0, ref EndPointFrom);
				if (nBytes == SOCKET_ERROR) 
				{
					Console.WriteLine("Host not Responding") ;
					recd=true ;
					break;
				}
				else if(nBytes>0)
				{
					dwStop = System.Environment.TickCount - dwStart; // stop timing
					Console.WriteLine("Reply from "+epServer.ToString()+" in "+dwStop+"MS :Bytes Received"+nBytes);
					recd=true;
					break;
				}
				timeout=System.Environment.TickCount - dwStart;
				if(timeout>1000)
				{
					Console.WriteLine("Time Out") ;
					recd=true;
				}
				
			}
            
		//close the socket
        socket.Close();     
	}
	/// <summary>
	///  This method get the Packet and calculates the total size 
	///  of the Pack by converting it to byte array
	/// </summary>
	public static Int32 Serialize(  IcmpPacket packet, Byte [] Buffer, Int32 PacketSize, Int32 PingData )
    {
        Int32 cbReturn = 0;
        // serialize the struct into the array
        int Index=0;

        Byte [] b_type = new Byte[1];
        b_type[0] = (packet.Type);

        Byte [] b_code = new Byte[1];
        b_code[0] = (packet.SubCode);

        Byte [] b_cksum = BitConverter.GetBytes(packet.CheckSum);
        Byte [] b_id = BitConverter.GetBytes(packet.Identifier);
        Byte [] b_seq = BitConverter.GetBytes(packet.SequenceNumber);
        
        // Console.WriteLine("Serialize type ");
        Array.Copy( b_type, 0, Buffer, Index, b_type.Length );
        Index += b_type.Length;
        
        // Console.WriteLine("Serialize code ");
        Array.Copy( b_code, 0, Buffer, Index, b_code.Length );
        Index += b_code.Length;

        // Console.WriteLine("Serialize cksum ");
        Array.Copy( b_cksum, 0, Buffer, Index, b_cksum.Length );
        Index += b_cksum.Length;

        // Console.WriteLine("Serialize id ");
        Array.Copy( b_id, 0, Buffer, Index, b_id.Length );
        Index += b_id.Length;

        Array.Copy( b_seq, 0, Buffer, Index, b_seq.Length );
        Index += b_seq.Length;

        // copy the data	        
        Array.Copy( packet.Data, 0, Buffer, Index, PingData );
        Index += PingData;
        if( Index != PacketSize/* sizeof(IcmpPacket)  */) {
            cbReturn = -1;
            return cbReturn;
        }

        cbReturn = Index;
        return cbReturn;
    }
	/// <summary>
	///		This Method has the algorithm to make a checksum 
	/// </summary>
	public static UInt16 checksum( UInt16[] buffer, int size )
	{
	    Int32 cksum = 0;
	    int counter;

	    counter = 0;

        while ( size > 0 ) {

            UInt16 val = buffer[counter];

            cksum += Convert.ToInt32( buffer[counter] );
	        counter += 1;
	        size -= 1;
	    }

        cksum = (cksum >> 16) + (cksum & 0xffff);
	    cksum += (cksum >> 16);
	    return (UInt16)(~cksum);
	}
} // class ping
/// <summary>
///		Class that holds the Pack information
/// </summary>
public class IcmpPacket 
{ 
    public Byte  Type;    // type of message
    public Byte  SubCode;    // type of sub code
    public UInt16 CheckSum;   // ones complement checksum of struct
    public UInt16 Identifier;      // identifier
    public UInt16 SequenceNumber;     // sequence number  
    public Byte [] Data;

} // class IcmpPacket