public TcpPacket HandleTcpPacket()
{
TcpPacket packet = new TcpPacket();
int source_port = HeaderParser.ToInt(this.Data, 0, 16);
int dest_port = HeaderParser.ToInt(this.Data, 16, 16);
int offset = HeaderParser.ToInt(this.Data, 96, 4) * 4;
packet.Source = new IPEndPoint(this.Source, source_port);
packet.Destination = new IPEndPoint(this.Destination, dest_port);
packet.Sequence = HeaderParser.ToUInt(this.Data, 32, 32);
packet.Acknowledgement = HeaderParser.ToUInt(this.Data, 64, 32);
packet.DataOffset = offset;
packet.Urgent = HeaderParser.ToByte(this.Data, 106, 1) != 0;
packet.Ack = HeaderParser.ToByte(this.Data, 107, 1) != 0;
packet.Push = HeaderParser.ToByte(this.Data, 108, 1) != 0;
packet.Reset = HeaderParser.ToByte(this.Data, 109, 1) != 0;
packet.Syn = HeaderParser.ToByte(this.Data, 110, 1) != 0;
packet.Fin = HeaderParser.ToByte(this.Data, 111, 1) != 0;
packet.WindowSize = HeaderParser.ToInt(this.Data, 112, 16);
packet.Checksum = HeaderParser.ToInt(this.Data, 128, 16);
packet.UrgentPointer = HeaderParser.ToInt(this.Data, 144, 16);
if (offset > 20)
{
packet.SetData(this.Data, 20, offset - 20);
}
packet.SetData(this.Data, offset, this.Data.Length - offset);
return(packet);
}
public bool SetFields(Byte[] buffer)
{
if (buffer.Length >= this.HeaderLength_)
{
int [] x = new int[2];
for (int i = 0; i < Keys_.Count; i++)
{
x = (int[])FieldLengths_[Keys_[i]];
if (x[1] <= 8)
{
Fields_.Add(Keys_[i], HeaderParser.ToByte(buffer, x[0], x[1]));
}
else if (x[1] <= 16)
{
Fields_.Add(Keys_[i], HeaderParser.ToInt(buffer, x[0], x[1]));
}
else if (x[1] <= 32)
{
Fields_.Add(Keys_[i], HeaderParser.ToUInt(buffer, x[0], x[1]));
}
}
this.SetData(buffer, this.HeaderLength_, buffer.Length - this.HeaderLength_);
Length_ = buffer.Length;
return(true);
}
return(false);
}
public void SetPorts()
{
if (this.Protocol == 6 || this.Protocol == 17)
{
SPort = HeaderParser.ToInt(this.Data, 0, 16);
DPort = HeaderParser.ToInt(this.Data, 16, 16);
}
}
public UdpDatagram HandleUdpDatagram()
{
UdpDatagram packet = new UdpDatagram();
int source_port = HeaderParser.ToInt(this.Data, 0, 16);
int dest_port = HeaderParser.ToInt(this.Data, 16, 16);
int length = HeaderParser.ToInt(this.Data, 32, 16) - 8;
packet.Source = new IPEndPoint(this.Source, source_port);
packet.Destination = new IPEndPoint(this.Destination, dest_port);
packet.SetData(this.Data, 8, length);
return(packet);
}
public int GetInnerDataLength()
{
switch (this.Protocol)
{
case 1: return(this.Data.Length - 8);
case 6: return(this.Data.Length - HeaderParser.ToInt(this.Data, 96, 4) * 4);
case 17: return(HeaderParser.ToInt(this.Data, 32, 16) - 8);
default: return(0);
}
}
// Callback function for the Asynchronous Receive on a Socket.
private void ReceivePacket(IAsyncResult ar)
{
bool fired = false;
int len = 0;
SocketPair p = ar.AsyncState as SocketPair;
Socket socket = p.IPSocket;
int type = 0;
try
{
len = socket.EndReceive(ar);
}
catch (SocketException e)
{
fired = true;
FireSnifferError(new SnifferException("Error Receiving Packet", e));
}
if (!fired)
{
type = HeaderParser.ToInt(p.Buffer, 0, 4);
try
{
switch (type)
{
case 4:
HandleIPv4Datagram(p.Buffer);
break;
}
}
catch (Exception e)
{
FireSnifferError(new SnifferException(e.Message.ToString(), e));
}
}
if (!this.paused)
{
socket.BeginReceive(p.Buffer, 0, p.Buffer.Length, SocketFlags.None, new AsyncCallback(this.ReceivePacket), p);
}
}
// Parses out an IPv4 Datagram.
private void HandleIPv4Datagram(byte[] buffer)
{
int identification = 0;
int protocol = 0;
uint source = 0;
uint dest = 0;
int header_length = 0;
IPv4Datagram datagram = null;
IPAddress source_ip;
IPAddress dest_ip;
source = HeaderParser.ToUInt(buffer, 96, 32);
dest = HeaderParser.ToUInt(buffer, 128, 32);
source_ip = IPAddress.Parse(IPv4Datagram.GetIPString(source));
dest_ip = IPAddress.Parse(IPv4Datagram.GetIPString(dest));
if (isRelatedToThisCom(source_ip.ToString(), dest_ip.ToString()))
{
IPv4Fragment fragment = new IPv4Fragment();
fragment.MoreFlag = (HeaderParser.ToByte(buffer, 50, 1) > 0) ? true : false;
fragment.Offset = HeaderParser.ToInt(buffer, 51, 13) * 8;
fragment.TTL = HeaderParser.ToInt(buffer, 64, 8);
fragment.Length = HeaderParser.ToUShort(buffer, 16, 16);
header_length = HeaderParser.ToInt(buffer, 4, 4) * 4;
fragment.SetData(buffer, header_length, fragment.Length - header_length);
identification = HeaderParser.ToInt(buffer, 32, 16);
protocol = HeaderParser.ToByte(buffer, 72, 8);
// source = HeaderParser.ToUInt(buffer,96,32);
// dest = HeaderParser.ToUInt(buffer,128,32);
// source_ip = IPAddress.Parse(IPv4Datagram.GetIPString(source));
// dest_ip = IPAddress.Parse(IPv4Datagram.GetIPString(dest));
datagram = Data_.GetIPv4Datagram(identification, source_ip, dest_ip);
if (datagram == null)
{
datagram = new IPv4Datagram();
datagram.IHL = HeaderParser.ToInt(buffer, 4, 4) * 4;
datagram.TypeOfService = HeaderParser.ToInt(buffer, 8, 8);
datagram.ReservedFlag = HeaderParser.ToInt(buffer, 48, 1);
datagram.DontFragmentFlag = HeaderParser.ToInt(buffer, 49, 1);
datagram.Identification = identification;
datagram.TTL = HeaderParser.ToInt(buffer, 64, 8);
datagram.Checksum = HeaderParser.ToInt(buffer, 80, 16);
datagram.Source = source_ip;
datagram.SourceName = DnsTable.GetName(source_ip.ToString());
datagram.DestinationName = DnsTable.GetName(dest_ip.ToString());
datagram.Destination = dest_ip;
datagram.Protocol = protocol;
if (datagram.IHL == 24)
{
datagram.Options = HeaderParser.ToInt(buffer, 160, 32);
}
}
datagram.AddFragment(fragment);
if (datagram.Complete)
{
datagram.SetPorts();
if (FilterManager.isAllowed(datagram.GetUpperProtocol(), datagram.SourceIP, datagram.DestinationIP, datagram.SPort, datagram.DPort))
{
FireIPv4DatagramReceived(datagram);
datagram.SetHeader(buffer);
if (datagram.WasFragmented())
{
Data_.RemoveIPv4Datagram(datagram);
}
}
}
else
{
Data_.AddIPv4Datagram(datagram);
this.FireIPv4FragmentReceived(fragment);
}
}
}