public static byte[] CreatePacket(REQUEST req)
{
Byte[] ByteSend = new Byte[PACKET_SIZE + 8];
//Create Byte array from REQUEST structure
ByteSend[0] = req.m_icmp.type;
ByteSend[1] = req.m_icmp.code;
Array.Copy(BitConverter.GetBytes(req.m_icmp.checksum), 0, ByteSend, 2, 2);
Array.Copy(BitConverter.GetBytes(req.m_icmp.id), 0, ByteSend, 4, 2);
Array.Copy(BitConverter.GetBytes(req.m_icmp.seq), 0, ByteSend, 6, 2);
for (int i = 0; i < req.m_data.Length; i++)
{
ByteSend[i + 8] = req.m_data[i];
}
//calculate checksum
int iCheckSum = 0;
for (int i = 0; i < ByteSend.Length; i += 2)
{
iCheckSum += Convert.ToInt32(BitConverter.ToUInt16(ByteSend, i));
}
iCheckSum = (iCheckSum >> 16) + (iCheckSum & 0xffff);
iCheckSum += (iCheckSum >> 16);
//update byte array to reflect checksum
Array.Copy(BitConverter.GetBytes((ushort)~iCheckSum), 0, ByteSend, 2, 2);
return(ByteSend);
}
public static TraceResults TraceHost(string host)
{
TraceResults results = new TraceResults();
results.Host = host;
try {
//Create Raw ICMP Socket
Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Raw, ProtocolType.Icmp);
//destination
IPEndPoint ipdest = new IPEndPoint(Dns.Resolve(host).AddressList[0], 80);
//Source
IPEndPoint ipsrc = new IPEndPoint(Dns.GetHostByName(Dns.GetHostName()).AddressList[0], 80);
EndPoint epsrc = (EndPoint)ipsrc;
ICMP ip = new ICMP();
ip.type = ICMPConstants.ICMP_ECHOREQ;
ip.code = 0;
ip.checksum = 0;
ip.id = (ushort)DateTime.Now.Millisecond; //any number you feel is kinda unique :)
ip.seq = 0;
REQUEST req = new REQUEST();
req.m_icmp = ip;
req.m_data = new Byte[PACKET_SIZE];
//Initialize data
for (int i = 0; i < req.m_data.Length; i++)
{
req.m_data[i] = (byte)'S';
}
//this function would gets byte array from the REQUEST structure
Byte[] ByteSend = CreatePacket(req);
//send requests with increasing number of TTL
for (int ittl = 1; ittl <= ICMPConstants.MAX_TTL; ittl++)
{
TraceResult tr = new TraceResult();
tr.TTL = ittl;
Byte[] ByteRecv = new Byte[256];
//Socket options to set TTL and Timeouts
s.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.IpTimeToLive, ittl);
s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.SendTimeout, 10000);
s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 10000);
//Get current time
DateTime dt = DateTime.Now;
//Send Request
int iRet = s.SendTo(ByteSend, ByteSend.Length, SocketFlags.None, ipdest);
//check for Win32 SOCKET_ERROR
if (iRet == -1)
{
tr.HostName = "error sending data";
}
//Receive
iRet = s.ReceiveFrom(ByteRecv, ByteRecv.Length, SocketFlags.None, ref epsrc);
//Calculate time required
TimeSpan ts = DateTime.Now - dt;;
//check if response is OK
if (iRet == -1)
{
tr.HostName = "error getting data";
}
IPAddress addy = ((IPEndPoint)epsrc).Address;
tr.IP = addy.ToString();
tr.Time = ts.Milliseconds;
results.AddResult(tr);
//reply size should be sizeof REQUEST + 20 (i.e sizeof IP header),it should be an echo reply
//and id should be same
if ((iRet == PACKET_SIZE + 8 + 20) && (BitConverter.ToInt16(ByteRecv, 24) == BitConverter.ToInt16(ByteSend, 4)) && (ByteRecv[20] == ICMPConstants.ICMP_ECHOREPLY))
{
break;
}
//time out
if (ByteRecv[20] != ICMPConstants.ICMP_TIMEEXCEEDED)
{
tr.HostName = "unexpected reply, quitting...";
break;
}
}
}
catch (SocketException e) {
results.Error = e.ToString();
results.HasError = true;
}
catch (Exception e) {
results.Error = e.ToString();
results.HasError = true;
}
return(results);
}
