miniFilter 内核层与应用程序通信

重点说下FltSendMessage() FilterGetMessage() 和 FilterReplyMessage() 这三个函数

 

首先：内核层的结构体

//  Defines the commands between the utility and the filter

typedef enum _NPMINI_COMMAND {

	ENUM_PASS = 0,

	ENUM_BLOCK

} NPMINI_COMMAND;	



//  Defines the command structure between the utility and the filter.

typedef struct _COMMAND_MESSAGE {

	NPMINI_COMMAND 	Command;  

	ULONG ulValue;

} COMMAND_MESSAGE, *PCOMMAND_MESSAGE;

 应用层通讯需要用到的结构体

 1 typedef struct _COMMAND_MESSAGE {
 2     NPMINI_COMMAND     Command;  
 3     ULONG ulValue;
 4 } COMMAND_MESSAGE, *PCOMMAND_MESSAGE;
 5 
 6 
 7 typedef struct _USERCOMMAND_MESSAGE {
 8     FILTER_MESSAGE_HEADER messageHeader;
 9     COMMAND_MESSAGE cmdMessage;
10 }USERCOMMAND_MESSAGE, *PUSERCOMMAND_MESSAGE;
11 
12 typedef struct _USERCOMMAND_MESSAGE_REPLAY
13 {
14     FILTER_REPLY_HEADER  replayHeader;
15     COMMAND_MESSAGE cmdMessage;
16 
17 }USERCOMMAND_MESSAGE_REPLAY,*PUSERCOMMAND_MESSAGE_REPLAY;

内核里的调用

View Code

 1 //发送的数据
 2                         COMMAND_MESSAGE gCmdMessageSend;
 3 
 4                         gCmdMessageSend.Command=ENUM_PASS;
 5                         gCmdMessageSend.ulValue=100;
 6                         
 7                         //接收的数据
 8                         COMMAND_MESSAGE gCmdMessageGet;
 9 
10                         timeout.HighPart=10000000;
11                         
12                         
13                         ULONG ulReplayLength=sizeof(COMMAND_MESSAGE);
14 
15                         status=FltSendMessage(gFilterHandle,&gClientPort,&gCmdMessageSend,sizeof(COMMAND_MESSAGE),&gCmdMessageGet,&ulReplayLength,NULL);
16                         
17                          
18 
19                         KdPrint(("after FltSendMessage %x,%d,%d \n",status,ulReplayLength,gCmdMessageGet.ulValue));

这里FltSendMessage必须等到FilterGetMessage和FilterReplyMessage全部返回正确才能够继续运行 否则挂起

应用层的调用

View Code

 1 USERCOMMAND_MESSAGE data;
 2     USERCOMMAND_MESSAGE_REPLAY dataReplay;
 3 
 4     while(TRUE)
 5     {
 6         data->cmdMessage.ulValue=10;
 7         HRESULT hr= FilterGetMessage(g_hPort,(PFILTER_MESSAGE_HEADER)data,sizeof(USERCOMMAND_MESSAGE),NULL);
 8 
 9 
10         if (hr==S_OK)
11         {
12             CString    str;
13             str.Format(_T("%d"),data->cmdMessage.ulValue);
14 
15             dataReplay->replayHeader.MessageId=data->messageHeader.MessageId;
16 
17             //返回数据
18             dataReplay->cmdMessage.ulValue=10;
19             hr=FilterReplyMessage(g_hPort,(PFILTER_REPLY_HEADER)dataReplay,sizeof(COMMAND_MESSAGE)+sizeof(FILTER_REPLY_HEADER));
20 
21 
22         }
23     }