/// <summary>
/// http://blogs.technet.com/b/netmon/archive/2009/10/07/using-nmapi-to-access-tcp-payload.aspx
/// use property: property.tcppayloadlength, fields: tcp.srcport, tcp.dataoffset.dataoffset to calculate the payload length, and the offset in the raw frame.
/// use NmGetPartialRawFrame to get the payload.
/// </summary>
private void GetTcpPayLoad()
{
unsafe
{
uint ret;
byte tcpHeaderSize; //
uint tcpSrcOffset, tcpSrcSize; // offset: bits
var tcpPayloadLength = PropertyValueDict[NetmonPropertyName.TcpPayloadLength];
int payloadlen;
bool result = Int32.TryParse(tcpPayloadLength.ToString(), out payloadlen);
// Allocate a buffer for payload data. The maximum length=1460 bytes
IntPtr buff = Marshal.AllocHGlobal(1500);
if (payloadlen > 0)
{
// Get the Data Offset, used to determine the TCP header size
ret = NetmonAPI.NmGetFieldValueNumber8Bit(_FrameInfoUnit.ParsedFrame, _FrameInfoUnit.FieldIdDict[NetmonFieldName.TcpDataSet], out tcpHeaderSize);
//Get the Offset of TCP.SrcPort which is the first field in TCP.
ret = NetmonAPI.NmGetFieldOffsetAndSize(_FrameInfoUnit.ParsedFrame, _FrameInfoUnit.FieldIdDict[NetmonFieldName.TcpSrcPort], out tcpSrcOffset, out tcpSrcSize);
// Read in the partial frame. The Offset is in bits. TCPHeaderSize is off by a factor of 4.
uint retlen;
uint offset = (uint)(tcpSrcOffset / 8 + tcpHeaderSize * 4);
ret = NetmonAPI.NmGetPartialRawFrame(_FrameInfoUnit.RawFrame, offset, (uint)payloadlen, (byte *)buff, out retlen);
// cast the intptr to the byte.
byte[] _payload = new byte[payloadlen];
Marshal.Copy(buff, _payload, 0, payloadlen);
//var str = Encoding.Default.GetString(_payload);
frameUnit.fieldUnit.PayLoad = _payload;
/*
* if (protocolname == "TCP")
* {
* frameUnit.fieldUnit.tcpPayLoad = _payload;
* }
* else
* {
* frameUnit.fieldUnit.httpPayLoad = _payload;
* // Console.WriteLine("http payload:");
* //Console.WriteLine(str);
* }*/
}
Marshal.Release(buff);
}
}
public static string GetFramePayload(IntPtr RawFrame, uint TCPSrcOffset, uint TCPHeaderSize, uint paylen)
{
#region comm
//string tempstring = string.Empty;
//uint errno = 0;
//byte[] result = null;
//NM_NPL_PROPERTY_INFO propinfo = new NM_NPL_PROPERTY_INFO();
//propinfo.Size = (ushort)System.Runtime.InteropServices.Marshal.SizeOf(propinfo);
//errno = NetmonAPI.NmGetPropertyInfo(mFrameParser, mTCPPayLoadLengthID, ref propinfo);
//if (errno != 0)
//{
// Console.WriteLine("Error NmGetPropertyInfo Frame # error : " + errno.ToString());
//}
//byte[] val = new byte[propinfo.ValueSize];
//uint retlen;
//NmPropertyValueType vtype;
//unsafe
//{
// fixed (byte* pstr = val)
// {
// errno = NetmonAPI.NmGetPropertyById(mFrameParser, mTCPPayLoadLengthID, propinfo.ValueSize, pstr, out retlen, out vtype, 0, null);
// }
//}
//if (errno != 0)
//{
// Console.WriteLine("Error NmGetPropertyById Frame" + errno.ToString());
//}
//uint paylen = (uint)val[0] + ((uint)val[1] << 8) + ((uint)val[2] << 16) + ((uint)val[3] << 24);
//// Get the Data Offset, used to determine the TCP header size
//byte TCPHeaderSize;
//errno = NetmonAPI.NmGetFieldValueNumber8Bit(hParsedFrame, mTCPDataOffsetID, out TCPHeaderSize);
//if (errno != 0)
//{
// Console.WriteLine("Error NmGetFieldValueNumber8Bit Frame #error : " + errno.ToString());
//}
//// Get the Offset of TCP.SrcPort which is the first field in TCP.
//uint TCPSrcOffset;
//uint TCPSrcSize;
//errno = NetmonAPI.NmGetFieldOffsetAndSize(hParsedFrame, mTCPSrcPortID, out TCPSrcOffset, out TCPSrcSize);
//if (errno != 0)
//{
// Console.WriteLine("Error NmGetFieldValueNumber8Bit Frame # error : " + errno.ToString());
//}
#endregion
uint retlen;
uint errno = 0;
byte[] result = null;
string tempstring = string.Empty;
if (paylen > 0)
{
result = new byte[paylen];
unsafe
{
fixed(byte *pstr = result)
{
errno = NetmonAPI.NmGetPartialRawFrame(RawFrame, (uint)(TCPSrcOffset / 8 + TCPHeaderSize * 4), paylen, pstr, out retlen);
// errno = NetmonAPI.NmGetPartialRawFrame(RawFrame, (uint)(TCPSrcOffset / 8 ), paylen, pstr, out retlen);
}
}
if (errno != 0)
{
Console.WriteLine("Error NmGetFieldValueNumber8Bit Frame #error : " + errno.ToString());
result = null;
}
else
{
tempstring = Encoding.UTF8.GetString(result, 0, result.Length);
}
}
else
{
retlen = 0;
}
return(tempstring);
}
/// <summary>
/// Callback function for capture.
/// </summary>
/// <param name="hCapEngine"></param>
/// <param name="adapterIndex"></param>
/// <param name="callerContext"></param>
/// <param name="hRawFrame"></param>
private void CaptureCallBack(IntPtr hCapEngine, uint adapterIndex, IntPtr callerContext, IntPtr hRawFrame)
{
if (callerContext != IntPtr.Zero)
{
uint errno;
unsafe
{
uint frameLen = 0;
errno = NetmonAPI.NmGetRawFrameLength(hRawFrame, out frameLen);
if (errno != 0)
{
return;
}
byte[] frameBuf = new byte[CapturedFrameSize];
fixed(byte *pBuf = frameBuf)
{
if (frameLen >= CapturedFrameSize)
{
NM_TIME pTime = new NM_TIME();
//Get the TimeStamp of the frame for building the new shortened frame
errno = NetmonAPI.NmGetFrameTimeStampEx(hRawFrame, ref pTime);
if (errno != 0)
{
return;
}
uint captureSize = 0;
//use NmGetPartiaRawlFrame() to get the wanted length of the raw frame,
errno = NetmonAPI.NmGetPartialRawFrame(
hRawFrame,
0, //offset
CapturedFrameSize,
pBuf,
out captureSize
);
if (errno != 0)
{
return;
}
IntPtr hPartialRawFrame;
errno = NetmonAPI.NmBuildRawFrameFromBufferEx(
(IntPtr)pBuf,
CapturedFrameSize,
0, //media type, optional
ref pTime,
out hPartialRawFrame
);
if (errno != 0)
{
return;
}
NetmonAPI.NmAddFrame(callerContext, hPartialRawFrame);
}
else
{
NetmonAPI.NmAddFrame(callerContext, hRawFrame);
}
}
}
}
}
