public IpV4Header(byte[] byBuffer, int nReceived)
{
_dataGram = new BitArrayReader(byBuffer);
try
{
// The first eight bits of the IP header contain the version and
// header length so we read them.
_version = (int)_dataGram.ReadInt(4);
_headerLength = (byte)(_dataGram.ReadByte(4) * 4);
_dscp = _dataGram.ReadByte(6);
_ecn = _dataGram.ReadByte(2);
_totalLength = _dataGram.ReadShort();
_identification = _dataGram.ReadShort();
_flags = _dataGram.ReadByte(3);
_fragmentOffset = _dataGram.ReadShort(13);
_timeToLive = _dataGram.ReadByte();
_protocolType = (Protocol)_dataGram.ReadByte();
_checksum = (short)_dataGram.ReadShort();
_srcIP = _dataGram.ReadInt().Reverse();
_destIP = _dataGram.ReadInt().Reverse();
_dataGram.CurrentPositionInBytes = _headerLength;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Network Sniffer", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
public UdpHeader(BitArrayReader dataGram, int nReceived)
{
_dataGram = dataGram;
// The first sixteen bits contain the source port.
_sourcePort = _dataGram.ReadShort();
// The next sixteen bits contain the destination port.
_destinationPort = _dataGram.ReadShort();
// The next sixteen bits contain the length of the UDP packet.
_length = _dataGram.ReadShort();
// The next sixteen bits contain the checksum.
_checksum = (short)_dataGram.ReadShort();
//_dataGram already in correct position
}
public IcmpHeader(BitArrayReader dataGram, int nReceived)
{
// ICMP type
_Type = dataGram.ReadByte();
// ICMP subtype
_Code = dataGram.ReadByte();
// Error checking data, calculated from the ICMP header and data, with value 0 substituted for this field. The Internet Checksum is used, specified in RFC 1071
_Checksum = dataGram.ReadShort();
// Four-bytes field, contents vary based on the ICMP type and code.
_Header = dataGram.ReadInt();
}
public IgmpHeader(BitArrayReader dataGram, int nReceived)
{
// ICMP type
_Type = dataGram.ReadByte();
// ICMP subtype
_MaxRespCode = dataGram.ReadByte();
// Error checking data, calculated from the ICMP header and data, with value 0 substituted for this field. The Internet Checksum is used, specified in RFC 1071
_Checksum = dataGram.ReadShort();
_GroupAddress = new IPAddress(dataGram.ReadInt().Reverse());
if (_Type == 0x11)
{
_Resv = dataGram.ReadByte(4);
_SFlag = dataGram.ReadByte(1);
_QRV = dataGram.ReadByte(3);
_QQIC = dataGram.ReadByte();
_NumberofSources = dataGram.ReadShort();
}
// Four-bytes field, contents vary based on the ICMP type and code.
//_Header = (uint)IPAddress.NetworkToHostOrder(binaryReader.ReadInt32());
}
public DnsHeader(BitArrayReader dataGram)
{
// First sixteen bits are for identification.
_identification = dataGram.ReadShort();
// Next sixteen contain the flags.
_flags = dataGram.ReadShort();
// Read the total numbers of questions in the quesion list.
_totalQuestions = dataGram.ReadShort();
// Read the total number of answers in the answer list.
_totalAnswerRRs = dataGram.ReadShort();
// Read the total number of entries in the authority list.
_totalAuthorityRRs = dataGram.ReadShort();
// Total number of entries in the additional resource record list.
_totalAdditionalRRs = dataGram.ReadShort();
}
public TcpHeader(BitArrayReader dataGram, int nReceived)
{
_dataGram = dataGram;
try
{
// The first sixteen bits contain the source port.
_sourcePort = _dataGram.ReadShort();
// The next sixteen contain the destiination port.
_destinationPort = _dataGram.ReadShort();
// Next thirty two have the sequence number.
_sequenceNumber = _dataGram.ReadInt();
// Next thirty two have the acknowledgement number.
_acknowledgementNumber = _dataGram.ReadInt();
// The next sixteen bits hold the flags and the data offset.
_headerLength = _dataGram.ReadByte(4);
_dataGram.SkipBits(3);
_nFlags = _dataGram.ReadShort(9);
// The next sixteen contain the window size.
_window = _dataGram.ReadShort();
// In the next sixteen we have the checksum.
_checksum = (short)_dataGram.ReadShort();
// The following sixteen contain the urgent pointer.
_urgentPointer = _dataGram.ReadShort();
//// The data offset indicates where the data begins, so using it we
//// calculate the header length.
//_headerLength = (byte)(_dataOffset >> 12);
_headerLength *= 4;
//// Message length = Total length of the TCP packet - Header length.
//_messageLength = (ushort)(nReceived - _headerLength);
//// Copy the TCP data into the data buffer.
//_nFlags = _dataOffset & 0x3F;
_dataGram.CurrentPositionInBytes = _headerLength;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Network Sniffer" + (nReceived), MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
