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PING 是一個用來檢測網絡連接速度的工具，它會在本機和給出的遠程主機名之間建立一個SOCKET 連接并向其發送一個ICMP協議格式的數據包，然后遠程主機作出響應，發回一個數據包，通過計算發送到接收數據包的時間間隔，我們可以確定連接的速度。

使用方法 ping <hostname> [/r]

<hostname> 主機名

[/r] 可選屬性，決定是否連續的 ping 遠程主機。

下面是代碼：

///ping.cs

namespace SaurabhPing

{

using System;

using System.Net;

using System.Net.Sockets;

/// <summary>

/// 主要的類:ping

/// </summary>

class Ping

{

//聲明幾個常量

const int SOCKET_ERROR = -1;

const int ICMP_ECHO = 8;

/// <summary>

/// 這里取得Hostname參數

/// </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 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 occurred

Console.WriteLine("Error in Arguments") ;

}

}

/// <summary>

/// 主要的方法，用來取得IP，

/// 并計算響應時間

/// </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.AfINet, SocketType.SockRaw, ProtocolType.ProtICMP);

// 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 Method 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.Ceil( double_length / 2);

int cksum_buffer_length = Convert.ToInt32(dtemp);

//Create a Byte Array

UInt16 [] cksum_buffer = new UInt16[cksum_buffer_length];

//Code to initialize 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

}