// 初始化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 )
{
return "Error Creating Packet";
}
// convert 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 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 )
{
return "Error Creating Packet";
}
dwStart = System.Environment.TickCount; // Start timing
//send the Packet over the socket
if ((nBytes = socket.SendTo(sendbuf, PacketSize, 0, epServer)) == SOCKET_ERROR)
{
return "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)
{
return "主机没有响应" ;
//close the socket
socket.Close();
return "";
}
/// <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);
Array.Copy( b_type, 0, Buffer, Index, b_type.Length );
Index += b_type.Length;
Array.Copy( b_code, 0, Buffer, Index, b_code.Length );
Index += b_code.Length;
Array.Copy( b_cksum, 0, Buffer, Index, b_cksum.Length );
Index += b_cksum.Length;
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 = (cksum >> 16) + (cksum & 0xffff);
cksum += (cksum >> 16);
return (UInt16)(~cksum);
}
}
/// 类结束
/// <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;