Hi
I've taken this code from one of my tutors for my dissertation. The program is SimplePing, its on the net somewhere but I'll post it here anyway:
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
class SimplePing
{
public static void Main(string[] argv)
{
byte[] data = new byte[1024];
int recv;
Socket host = new Socket(AddressFamily.InterNetwork, SocketType.Raw,
ProtocolType.Icmp);
IPEndPoint iep = new IPEndPoint(IPAddress.Parse(argv[0]), 0);
EndPoint ep = (EndPoint)iep;
ICMP packet = new ICMP();
packet.Type = 0x08;
packet.Code = 0x00;
packet.Checksum = 0;
Buffer.BlockCopy(BitConverter.GetBytes((short)1), 0, packet.Message, 0, 2);
Buffer.BlockCopy(BitConverter.GetBytes((short)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);
host.SendTo(packet.getBytes(), packetsize, SocketFlags.None, iep);
try
{
data = new byte[1024];
recv = host.ReceiveFrom(data, ref ep);
} catch (SocketException)
{
Console.WriteLine("No response from remote host");
return;
}
ICMP response = new ICMP(data, recv);
Console.WriteLine("response from: {0}", ep.ToString());
Console.WriteLine(" Type {0}", response.Type);
Console.WriteLine(" Code: {0}", response.Code);
int Identifier = BitConverter.ToInt16(response.Message, 0);
int Sequence = BitConverter.ToInt16(response.Message, 2);
Console.WriteLine(" Identifier: {0}", Identifier);
Console.WriteLine(" Sequence: {0}", Sequence);
string stringData = Encoding.ASCII.GetString(response.Message, 4, response.MessageSize - 4);
Console.WriteLine(" data: {0}", stringData);

host.Close();
}
}
 
What I want to do is split the program in half so one of the computers communicating sits and waits until it sees a icmp request packet that is sent from the other computer running the full version of simple ping. This is what I've done so far:
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
class SimplePing
{
public static void Main()
{
byte[] data = new byte[1024];
int recv = 0;
Socket host = new Socket(AddressFamily.InterNetwork, SocketType.Raw,
ProtocolType.Icmp);
IPEndPoint iep = new IPEndPoint(IPAddress.Any, 0);
EndPoint ep = (EndPoint)iep;
host.Bind(ep);

data = new byte[1024];
Console.WriteLine("Waiting to receive datagrams from client...");
recv = host.ReceiveFrom(data, ref ep);
host.Close();


ICMP response = new ICMP(data, recv);
Console.WriteLine("response from: {0}", ep.ToString());
Console.WriteLine(" Type {0}", response.Type);
Console.WriteLine(" Code: {0}", response.Code);
int Identifier = BitConverter.ToInt16(response.Message, 0);
int Sequence = BitConverter.ToInt16(response.Message, 2);
Console.WriteLine(" Identifier: {0}", Identifier);
Console.WriteLine(" Sequence: {0}", Sequence);
string stringData = Encoding.ASCII.GetString(response.Message, 4, response.MessageSize - 4);
Console.WriteLine(" data: {0}", stringData);
host.Close();
}
}
If you want to rebuild this program it might help to download the code for ICMP.cs as follows:
using System;
using System.Net;
using System.Text;
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);
}
}
Any suggestions would be helpful, thanks
Dan