private void HandleIPv4Datagram(byte[] buffer)
{
int identification = 0;
int num2 = 0;
uint addr = 0;
uint num4 = 0;
int offset = 0;
IPv4Datagram datagram = null;
IPv4Fragment fragment = new IPv4Fragment();
fragment.MoreFlag = Sniffer.HeaderParser.ToByte(buffer, 50, 1) > 0;
fragment.Offset = Sniffer.HeaderParser.ToInt(buffer, 0x33, 13) * 8;
fragment.TTL = Sniffer.HeaderParser.ToInt(buffer, 0x40, 8);
fragment.Length = Sniffer.HeaderParser.ToUShort(buffer, 0x10, 0x10);
offset = Sniffer.HeaderParser.ToInt(buffer, 4, 4) * 4;
fragment.SetData(buffer, offset, fragment.Length - offset);
identification = Sniffer.HeaderParser.ToByte(buffer, 0x20, 0x10);
num2 = Sniffer.HeaderParser.ToByte(buffer, 0x48, 8);
addr = Sniffer.HeaderParser.ToUInt(buffer, 0x60, 0x20);
num4 = Sniffer.HeaderParser.ToUInt(buffer, 0x80, 0x20);
IPAddress source = IPAddress.Parse(IPv4Datagram.GetIPString(addr));
IPAddress dest = IPAddress.Parse(IPv4Datagram.GetIPString(num4));
datagram = this.m_Data.GetIPv4Datagram(identification, source, dest);
if (datagram == null)
{
datagram = new IPv4Datagram();
datagram.Identification = identification;
datagram.Source = source;
datagram.Destination = dest;
datagram.Protocol = num2;
}
datagram.AddFragment(fragment);
if (!datagram.Complete)
{
this.m_Data.AddIPv4Datagram(datagram);
this.FireIPv4FragmentReceived(fragment);
}
else
{
this.FireIPv4DatagramReceived(datagram);
switch (datagram.Protocol)
{
case 6:
this.HandleTcpPacket(datagram.Data, datagram.Source, datagram.Destination);
break;
case 0x11:
this.HandleUdpDatagram(datagram.Data, datagram.Source, datagram.Destination);
break;
}
if (datagram.WasFragmented())
{
this.m_Data.RemoveIPv4Datagram(datagram);
}
}
}
// 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);
}
}
}