ping程序的C#实现

编了一个.Net下的ping控制台程序，虽然简单，但是可见.Net的强大！
以下是程序源码，望大家多多跟贴，讨论改进，一起成长！
namespace Cornfield
{
using System;
using System.Net;
using System.Net.Sockets;

class MyPing
{

public static void Main(string[] argv)
{
if(argv.Length==1 || argv.Length==2)
PingHost(argv);
else
{
Console.WriteLine("Invalid Command.");
Console.WriteLine("Usage : 1. MyPing <hostname>.") ;
Console.WriteLine(" 2. MyPing <hostname> <client>.");
}

}

public static void PingHost(string[] hostclient)
{
file://初始化Socket套接字
file://三个参数分别为：
// 1。解析地址的地址模式，较常用的为AddressFamily.InterNetwork，即IPv4地址。
// 2。Socket套接字类型，一般为SocketType.Raw原始类型。
// 3。网络协议类型，这里Ping用的是Internet控制报文协议ProtocolType.Icmp.
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp);

IPHostEntry hostInfo;
try
{
file://解析主机IP入口
hostInfo = Dns.GetHostByName(hostclient[0]);
}
catch(Exception)
{
file://解析主机名错误。
Console.WriteLine("Unknown host {0}.",hostclient[0]);
return ;
}
// 取主机0号端口
EndPoint hostPoint= (EndPoint)new IPEndPoint(hostInfo.AddressList[0], 0);
IPHostEntry clientInfo;
try
{
if (hostclient.Length==2)
clientInfo =Dns.GetHostByName(hostclient[1]);
else
clientInfo = Dns.GetHostByName(Dns.GetHostName());
}
catch(Exception)
{
file://解析主机名错误。
Console.WriteLine("Unknown client {1}.",hostclient[1]);
return ;
}
// 取客户机0号端口
file://********************************注意******************************
file://这里当然可以设置为本地机或其它主机的IP,那样报文将返回到该机IP端口，
file://实际上这是黑客们惯用的手段之一，即利用报文协议来攻击远程主机
file://便是利用这样的原理，加上多个无限次的报文攻击即可时远程主机瘫痪
file://对于将本程序利用于非法的攻击活动，笔者概不负责!!!!!!!!!!!!!!!!
file://******************************************************************
EndPoint clientPoint = (EndPoint)new IPEndPoint(clientInfo.AddressList[0], 0);
file://设置ICMP报文
int DataSize = 32; // ICMP数据包大小;
int PacketSize = DataSize + 8;//总报文长度
const int ICMP_ECHO = 8;
IcmpPacket packet = new IcmpPacket(ICMP_ECHO,0,0,45,0,DataSize);

Byte [] Buffer = new Byte[ PacketSize ];
int index=packet.ConvertToByte(Buffer);
file://报文出错
if( index != PacketSize)
{
Console.WriteLine("There is something wrong with Packet Data !");
return ;
}
int cksum_buffer_length =(int)Math.Ceiling( ((Double)index)/ 2);
UInt16 [] cksum_buffer = new UInt16[cksum_buffer_length];
int icmp_header_buffer_index = 0;
for( int i = 0; i < cksum_buffer_length; i++ )
{
file://将两个byte转化为一个UInt16
cksum_buffer[i] = BitConverter.ToUInt16(Buffer,icmp_header_buffer_index);
icmp_header_buffer_index += 2;
}
file://将校验和保存至报文里
packet.CheckSum =IcmpPacket.SumOfCheck(cksum_buffer);
// 保存校验和后，再次将报文转化为数据包
Byte [] SendData = new Byte[ PacketSize ];
index= packet.ConvertToByte(SendData);
file://报文出错
if( index != PacketSize)
{
Console.WriteLine("There is something wrong with Packet Data !");
return ;
}

int nBytes=0;
file://系统计时开始
int startTime = Environment.TickCount;
file://发送数据包
if ((nBytes = socket.SendTo(SendData, PacketSize, SocketFlags.None,(EndPoint) hostPoint)) == -1)
{
Console.WriteLine("Socket can not send packet");
}

Byte [] ReceiveData = new Byte[256]; file://接收数据
nBytes = 0;
int timeout=0 ;
int timeConsume=0;
while(true)
{
nBytes = socket.ReceiveFrom(ReceiveData, 256,SocketFlags.None,ref clientPoint);
if (nBytes == -1)
{
Console.WriteLine("Host not Responding") ;
break;
}
else if(nBytes>0)
{
timeConsume = System.Environment.TickCount - startTime;
Console.WriteLine("Reply from "+hostPoint.ToString()+" in "
+timeConsume+"MS :Bytes Received"+nBytes);
break;
}
timeConsume=Environment.TickCount - startTime;
if(timeout>1000)
{
Console.WriteLine("Time Out") ;
break;
}
}

file://关闭套接字
socket.Close();
}
}

public class IcmpPacket
{
private Byte _type; // 报文类型
private Byte _subCode; // 字代码类型
private UInt16 _checkSum; // 报文校验和
private UInt16 _identifier; // 识别符
private UInt16 _sequenceNumber; // 序列号
private Byte [] _data; file://数据包
///***********************************************************
///初始化报文
///***********************************************************
public IcmpPacket(Byte type,Byte subCode,UInt16 checkSum,UInt16 identifier,UInt16 sequenceNumber,int dataSize)
{
_type=type;
_subCode=subCode;
_checkSum=checkSum;
_identifier=identifier;
_sequenceNumber=sequenceNumber;
_data=new Byte[dataSize];
for (int i = 0; i < dataSize; i++)
{
_data[i] = (byte)'#';
}
}
public UInt16 CheckSum
{
get
{
return _checkSum;
}
set
{
_checkSum=value;
}
}

///************************************************************
///将整个ICMP报文信息和数据转化为Byte数据包
///************************************************************
public int ConvertToByte(Byte[] buffer)
{
Byte [] b_type = new Byte[1]{_type};
Byte [] b_code = new Byte[1]{_subCode};
Byte [] b_cksum = BitConverter.GetBytes(_checkSum);
Byte [] b_id = BitConverter.GetBytes(_identifier);
Byte [] b_seq = BitConverter.GetBytes(_sequenceNumber);

int i=0;
Array.Copy( b_type, 0, buffer, i, b_type.Length );
i+= b_type.Length;

Array.Copy( b_code, 0, buffer, i, b_code.Length );
i+= b_code.Length;
Array.Copy( b_cksum, 0, buffer,i, b_cksum.Length );
i += b_cksum.Length;
Array.Copy( b_id, 0, buffer, i, b_id.Length );
i+= b_id.Length;
Array.Copy( b_seq, 0, buffer, i, b_seq.Length );
i += b_seq.Length;
Array.Copy(_data, 0, buffer, i, _data.Length );
i += _data.Length;
return i;
}
public static UInt16 SumOfCheck( UInt16[] buffer )
{
int cksum = 0;
for(int i=0;i<buffer.Length;i++)
cksum += (int) buffer[i];
cksum = (cksum >> 16) + (cksum & 0xffff);
cksum += (cksum >> 16);
return (UInt16)(~cksum);

}

}
}