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我一直在修改“检查”WFP 示例(与 WinDDK 捆绑在一起),目的是能够解析所有传入 TCP 数据包(来自指定 IP 地址)的有效负载以获取某些字符串。(我已经修改了“检查”,使得过滤器只捕获 TCP 数据包)

到目前为止,我的修改一直在'TLInspectTransportClassify'classifyFn上,如下所示。我的目标是访问捕获的每个 TCP 数据包的有效负载。

FWPS_STREAM_CALLOUT_IO_PACKET* ioPacket = (FWPS_STREAM_CALLOUT_IO_PACKET*)layerData;
FWPS_STREAM_DATA* streamData;
SIZE_T streamLength;
BYTE* stream = NULL;
SIZE_T bytesCopied = 0;

[...]

if(ioPacket == NULL) {
   DbgPrint("ioPacket == NULL\n");
   return STATUS_INSUFFICIENT_RESOURCES;
}
streamData = ioPacket->streamData;

if(!streamData) {     // why is this always NULL?  shouldn't our payload be here?
   DbgPrint("streamData == NULL: no data\n");   
   classifyOut->actionType = FWP_ACTION_PERMIT;
     classifyOut->rights &= ~FWPS_RIGHT_ACTION_WRITE;
     goto Exit;
}

DbgPrint("tcp packet has some data\n");

streamLength = streamData->dataLength;

stream =  ExAllocatePoolWithTag(NonPagedPool,
                               streamLength,
                               'yftN');

if (!stream)
  return STATUS_INSUFFICIENT_RESOURCES;

RtlZeroMemory(stream,streamLength);
FwpsCopyStreamDataToBuffer0(
  streamData,
  stream,
  streamLength,
  &bytesCopied);

// should now have our tcp payload in 'stream' buffer(?)

DbgPrint("reached parsing code\n");

[...]

据我了解,在如上所述声明 ioPacket 之后,ioPacket->streamData 应该包含数据包的有效负载。但是,ioPacket->streamData 对我来说始终为 NULL。如何获取数据包的有效负载?难道我做错了什么。

提前致谢。

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1 回答 1

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' TLInspectTransportClassify ' 位于TRANSPORT_LAYER上,其中layerData应转换为NET_BUFFER_LIST

FWPS_STREAM_CALLOUT_IO_PACKET用于 FWPM_LAYER_STREAM_V4/FWPM_LAYER_STREAM_V6

请参阅 MSDN 分类 Fn0。 http://msdn.microsoft.com/en-us/library/ff544890(VS.85).aspx

管理过滤层标识符 http://msdn.microsoft.com/en-us/library/ff557101(VS.85).aspx

于 2011-04-29T11:47:50.670 回答