驱动开发：内核封装WFP防火墙入门

WFP框架是微软推出来替代TDIHOOK传输层驱动接口网络通信的方案，其默认被设计为分层结构，该框架分别提供了用户态与内核态相同的AIP函数，在两种模式下均可以开发防火墙产品，以下代码我实现了一个简单的驱动过滤防火墙。

WFP 框架分为两大层次模块,用户态基础过滤引擎BFE (BaseFilteringEngine) ,以及内核态过滤引擎 KMFE (KMFilteringEngine),基础过滤引擎对上提供C语言调用方式的API以及RPC接口,这些接口都被封装在FWPUCLNT.dll模块中,开发时可以调用该模块中的导出函数.

• WFP程序工作流程:
• 使用 FwpmEngineOpen() 开启 WFP 引擎,获得WFP使用句柄
• 使用 FwpmTransactionBegin() 设置对网络通信内容的过滤权限 (只读/允许修改)
• 使用 FwpsCalloutRegister(),FwpmCalloutAdd(),FwpmFilterAdd() 选择要过滤的内容,并添加过滤器对象和回调函数.
• 使用 FwpmTransactionCommit() 确认刚才的内容,让刚才添加的回调函数开始生效.
• 使用 FwpmFilterDeleteById(),FwpmCalloutDeleteById(),FwpsCalloutUnregisterById()函数撤销对象和回调函数.
• 使用 FwpmEngineClose() 关闭WFP引擎类句柄.

默认情况下WFP一次需要注册3个回调函数,只有一个是事前回调,另外两个是事后回调,通常情况下我们只关注事前回调即可,此外WFP能过滤很对内容,我们需要指定过滤条件标志来输出我们所需要的数据.

• 一般可设置为FWPM_LAYER_ALE_AUTH_CONNECT_V4意思是设置IPV4过滤.
• 还需要设置一个GUID值,该值可随意设置,名称为GUID_ALE_AUTH_CONNECT_CALLOUT_V4宏.

首先我们通过上方的流程实现一个简单的网络控制驱动，该驱动运行后可对自身机器访问指定地址端口进行控制，例如实现指定应用断网，禁止指定页面被访问等，在配置WFP开发环境时需要在链接器选项卡中的附加依赖项中增加fwpkclnt.lib，uuid.lib这两个库文件，并且需要使用WDM开发模板，否则编译将不通过。

// 署名权
// right to sign one's name on a piece of work
// PowerBy: LyShark
// Email: [e-mail]#define NDIS_SUPPORT_NDIS6 1
#define DEV_NAME L"\\Device\\MY_WFP_DEV_NAME"
#define SYM_NAME L"\\DosDevices\\MY_WFP_SYM_NAME"#include <ntifs.h>
#include <fwpsk.h>
#include <fwpmk.h>
#include <stdio.h>// 过滤器引擎句柄
HANDLE g_hEngine;// 过滤器引擎中的callout的运行时标识符
ULONG32 g_AleConnectCalloutId;// 过滤器的运行时标识符
ULONG64 g_AleConnectFilterId;// 指定唯一UUID值(只要不冲突即可,内容可随意)
GUID GUID_ALE_AUTH_CONNECT_CALLOUT_V4 = { 0x6812fc83, 0x7d3e, 0x499a, 0xa0, 0x12, 0x55, 0xe0, 0xd8, 0x5f, 0x34, 0x8b };// ------------------------------------------------------------------------------
// 头部函数声明
// ------------------------------------------------------------------------------// 注册Callout并设置过滤点
NTSTATUS RegisterCalloutForLayer(IN PDEVICE_OBJECT pDevObj,IN const GUID *layerKey,IN const GUID *calloutKey,IN FWPS_CALLOUT_CLASSIFY_FN classifyFn,IN FWPS_CALLOUT_NOTIFY_FN notifyFn,IN FWPS_CALLOUT_FLOW_DELETE_NOTIFY_FN flowDeleteNotifyFn,OUT ULONG32 *calloutId,OUT ULONG64 *filterId,OUT HANDLE *engine);// 注册Callout
NTSTATUS RegisterCallout(PDEVICE_OBJECT pDevObj,IN const GUID *calloutKey,IN FWPS_CALLOUT_CLASSIFY_FN classifyFn,IN FWPS_CALLOUT_NOTIFY_FN notifyFn,IN FWPS_CALLOUT_FLOW_DELETE_NOTIFY_FN flowDeleteNotifyFn,OUT ULONG32 *calloutId);// 设置过滤点
NTSTATUS SetFilter(IN const GUID *layerKey,IN const GUID *calloutKey,OUT ULONG64 *filterId,OUT HANDLE *engine);// Callout函数 flowDeleteFn
VOID NTAPI flowDeleteFn(_In_ UINT16 layerId,_In_ UINT32 calloutId,_In_ UINT64 flowContext);// Callout函数 classifyFn
#if (NTDDI_VERSION >= NTDDI_WIN8)
VOID NTAPI classifyFn(_In_ const FWPS_INCOMING_VALUES0* inFixedValues,_In_ const FWPS_INCOMING_METADATA_VALUES0* inMetaValues,_Inout_opt_ void* layerData,_In_opt_ const void* classifyContext,_In_ const FWPS_FILTER2* filter,_In_ UINT64 flowContext,_Inout_ FWPS_CLASSIFY_OUT0* classifyOut);
#elif (NTDDI_VERSION >= NTDDI_WIN7)                       
VOID NTAPI classifyFn(_In_ const FWPS_INCOMING_VALUES0* inFixedValues,_In_ const FWPS_INCOMING_METADATA_VALUES0* inMetaValues,_Inout_opt_ void* layerData,_In_opt_ const void* classifyContext,_In_ const FWPS_FILTER1* filter,_In_ UINT64 flowContext,_Inout_ FWPS_CLASSIFY_OUT0* classifyOut);
#else
VOID NTAPI classifyFn(_In_ const FWPS_INCOMING_VALUES0* inFixedValues,_In_ const FWPS_INCOMING_METADATA_VALUES0* inMetaValues,_Inout_opt_ void* layerData,_In_ const FWPS_FILTER0* filter,_In_ UINT64 flowContext,_Inout_ FWPS_CLASSIFY_OUT0* classifyOut);
#endif// Callout函数 notifyFn
#if (NTDDI_VERSION >= NTDDI_WIN8)
NTSTATUS NTAPI notifyFn(_In_ FWPS_CALLOUT_NOTIFY_TYPE notifyType,_In_ const GUID* filterKey,_Inout_ FWPS_FILTER2* filter);
#elif (NTDDI_VERSION >= NTDDI_WIN7)
NTSTATUS NTAPI notifyFn(_In_ FWPS_CALLOUT_NOTIFY_TYPE notifyType,_In_ const GUID* filterKey,_Inout_ FWPS_FILTER1* filter);
#else
NTSTATUS NTAPI notifyFn(_In_ FWPS_CALLOUT_NOTIFY_TYPE notifyType,_In_ const GUID* filterKey,_Inout_ FWPS_FILTER0* filter);
#endif// ------------------------------------------------------------------------------
// 函数实现部分
// ------------------------------------------------------------------------------// 协议判断
NTSTATUS ProtocalIdToName(UINT16 protocalId, PCHAR lpszProtocalName)
{NTSTATUS status = STATUS_SUCCESS;switch (protocalId){case 1:{// ICMPRtlCopyMemory(lpszProtocalName, "ICMP", 5);break;}case 2:{// IGMPRtlCopyMemory(lpszProtocalName, "IGMP", 5);break;}case 6:{// TCPRtlCopyMemory(lpszProtocalName, "TCP", 4);break;}case 17:{// UDPRtlCopyMemory(lpszProtocalName, "UDP", 4);break;}case 27:{// RDPRtlCopyMemory(lpszProtocalName, "RDP", 6);break;}default:{// UNKNOWRtlCopyMemory(lpszProtocalName, "UNKNOWN", 8);break;}}return status;
}// 启动WFP
NTSTATUS WfpLoad(PDEVICE_OBJECT pDevObj)
{NTSTATUS status = STATUS_SUCCESS;// 注册Callout并设置过滤点// classifyFn, notifyFn, flowDeleteFn 注册三个回调函数,一个事前回调,两个事后回调status = RegisterCalloutForLayer(pDevObj, &FWPM_LAYER_ALE_AUTH_CONNECT_V4, &GUID_ALE_AUTH_CONNECT_CALLOUT_V4,classifyFn, notifyFn, flowDeleteFn, &g_AleConnectCalloutId, &g_AleConnectFilterId, &g_hEngine);if (!NT_SUCCESS(status)){DbgPrint("注册回调失败 \n");return status;}return status;
}// 卸载WFP
NTSTATUS WfpUnload()
{if (NULL != g_hEngine){// 删除FilterIdFwpmFilterDeleteById(g_hEngine, g_AleConnectFilterId);// 删除CalloutIdFwpmCalloutDeleteById(g_hEngine, g_AleConnectCalloutId);// 清空Filterg_AleConnectFilterId = 0;// 反注册CalloutIdFwpsCalloutUnregisterById(g_AleConnectCalloutId);// 清空CalloutIdg_AleConnectCalloutId = 0;// 关闭引擎FwpmEngineClose(g_hEngine);g_hEngine = NULL;}return STATUS_SUCCESS;
}// 注册Callout并设置过滤点
NTSTATUS RegisterCalloutForLayer(IN PDEVICE_OBJECT pDevObj, IN const GUID *layerKey, IN const GUID *calloutKey, IN FWPS_CALLOUT_CLASSIFY_FN classifyFn, IN FWPS_CALLOUT_NOTIFY_FN notifyFn, IN FWPS_CALLOUT_FLOW_DELETE_NOTIFY_FN flowDeleteNotifyFn, OUT ULONG32 *calloutId, OUT ULONG64 *filterId, OUT HANDLE *engine)
{NTSTATUS status = STATUS_SUCCESS;// 注册Calloutstatus = RegisterCallout(pDevObj, calloutKey, classifyFn, notifyFn, flowDeleteNotifyFn, calloutId);if (!NT_SUCCESS(status)){return status;}// 设置过滤点status = SetFilter(layerKey, calloutKey, filterId, engine);if (!NT_SUCCESS(status)){return status;}return status;
}// 注册Callout
NTSTATUS RegisterCallout(PDEVICE_OBJECT pDevObj, IN const GUID *calloutKey, IN FWPS_CALLOUT_CLASSIFY_FN classifyFn, IN FWPS_CALLOUT_NOTIFY_FN notifyFn, IN FWPS_CALLOUT_FLOW_DELETE_NOTIFY_FN flowDeleteNotifyFn, OUT ULONG32 *calloutId)
{NTSTATUS status = STATUS_SUCCESS;FWPS_CALLOUT sCallout = { 0 };// 设置CalloutsCallout.calloutKey = *calloutKey;sCallout.classifyFn = classifyFn;sCallout.flowDeleteFn = flowDeleteNotifyFn;sCallout.notifyFn = notifyFn;// 注册Calloutstatus = FwpsCalloutRegister(pDevObj, &sCallout, calloutId);if (!NT_SUCCESS(status)){DbgPrint("注册Callout失败 \n");return status;}return status;
}// 设置过滤点
NTSTATUS SetFilter(IN const GUID *layerKey, IN const GUID *calloutKey, OUT ULONG64 *filterId, OUT HANDLE *engine)
{HANDLE hEngine = NULL;NTSTATUS status = STATUS_SUCCESS;FWPM_SESSION session = { 0 };FWPM_FILTER mFilter = { 0 };FWPM_CALLOUT mCallout = { 0 };FWPM_DISPLAY_DATA mDispData = { 0 };// 创建Sessionsession.flags = FWPM_SESSION_FLAG_DYNAMIC;status = FwpmEngineOpen(NULL, RPC_C_AUTHN_WINNT, NULL, &session, &hEngine);if (!NT_SUCCESS(status)){return status;}// 开始事务status = FwpmTransactionBegin(hEngine, 0);if (!NT_SUCCESS(status)){return status;}// 设置Callout参数mDispData.name = L"MY WFP LyShark";mDispData.description = L"WORLD OF DEMON";mCallout.applicableLayer = *layerKey;mCallout.calloutKey = *calloutKey;mCallout.displayData = mDispData;// 添加Callout到Session中status = FwpmCalloutAdd(hEngine, &mCallout, NULL, NULL);if (!NT_SUCCESS(status)){return status;}// 设置过滤器参数mFilter.action.calloutKey = *calloutKey;mFilter.action.type = FWP_ACTION_CALLOUT_TERMINATING;mFilter.displayData.name = L"MY WFP LyShark";mFilter.displayData.description = L"WORLD OF DEMON";mFilter.layerKey = *layerKey;mFilter.subLayerKey = FWPM_SUBLAYER_UNIVERSAL;mFilter.weight.type = FWP_EMPTY;// 添加过滤器status = FwpmFilterAdd(hEngine, &mFilter, NULL, filterId);if (!NT_SUCCESS(status)){return status;}// 提交事务status = FwpmTransactionCommit(hEngine);if (!NT_SUCCESS(status)){return status;}*engine = hEngine;return status;
}// Callout函数 classifyFn 事前回调函数
VOID NTAPI classifyFn(_In_ const FWPS_INCOMING_VALUES0* inFixedValues, _In_ const FWPS_INCOMING_METADATA_VALUES0* inMetaValues, _Inout_opt_ void* layerData, _In_opt_ const void* classifyContext, _In_ const FWPS_FILTER2* filter, _In_ UINT64 flowContext, _Inout_ FWPS_CLASSIFY_OUT0* classifyOut)
{// 数据包的方向,取值 FWP_DIRECTION_INBOUND = 1 或 FWP_DIRECTION_OUTBOUND = 0WORD wDirection = inFixedValues->incomingValue[FWPS_FIELD_ALE_FLOW_ESTABLISHED_V4_DIRECTION].value.int8;// 定义本机地址与本机端口ULONG ulLocalIp = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_LOCAL_ADDRESS].value.uint32;UINT16 uLocalPort = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_LOCAL_PORT].value.uint16;// 定义对端地址与对端端口ULONG ulRemoteIp = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_REMOTE_ADDRESS].value.uint32;UINT16 uRemotePort = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_REMOTE_PORT].value.uint16;// 获取当前进程IRQKIRQL kCurrentIrql = KeGetCurrentIrql();// 获取进程IDULONG64 processId = inMetaValues->processId;UCHAR szProcessPath[256] = { 0 };CHAR szProtocalName[256] = { 0 };RtlZeroMemory(szProcessPath, 256);// 获取进程路径for (ULONG i = 0; i < inMetaValues->processPath->size; i++){// 里面是宽字符存储的szProcessPath[i] = inMetaValues->processPath->data[i];}// 获取当前协议类型ProtocalIdToName(inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_PROTOCOL].value.uint16, szProtocalName);// 设置默认规则 允许连接classifyOut->actionType = FWP_ACTION_PERMIT;// 禁止指定进程网络连接if (NULL != wcsstr((PWCHAR)szProcessPath, L"iexplore.exe")){// 设置拒绝规则 拒绝连接classifyOut->actionType = FWP_ACTION_BLOCK;classifyOut->rights = classifyOut->rights & (~FWPS_RIGHT_ACTION_WRITE);classifyOut->flags = classifyOut->flags | FWPS_CLASSIFY_OUT_FLAG_ABSORB;DbgPrint("[LyShark.com] 拦截IE网络链接请求... \n");}// 输出对端地址字符串 并阻断链接char szRemoteAddress[256] = { 0 };char szRemotePort[128] = { 0 };char szLocalAddress[256] = { 0 };char szLocalPort[128] = { 0 };sprintf(szRemoteAddress, "%u.%u.%u.%u", (ulRemoteIp >> 24) & 0xFF, (ulRemoteIp >> 16) & 0xFF, (ulRemoteIp >> 8) & 0xFF, (ulRemoteIp)& 0xFF);sprintf(szRemotePort, "%d", uRemotePort);sprintf(szLocalAddress, "%u.%u.%u.%u", (ulLocalIp >> 24) & 0xFF, (ulLocalIp >> 16) & 0xFF, (ulLocalIp >> 8) & 0xFF, (ulLocalIp)& 0xFF);sprintf(szLocalPort, "%d", uLocalPort);// DbgPrint("本端: %s : %s --> 对端: %s : %s \n", szLocalAddress, szLocalPort, szRemoteAddress, szRemotePort);// 如果对端地址是 8.141.58.64 且对端端口是 443 则拒绝连接if (strcmp(szRemoteAddress, "8.141.58.64") == 0 && strcmp(szRemotePort, "443") == 0){DbgPrint("[LyShark.com] 拦截网站访问请求 --> %s : %s \n", szRemoteAddress, szRemotePort);// 设置拒绝规则 拒绝连接classifyOut->actionType = FWP_ACTION_BLOCK;classifyOut->rights = classifyOut->rights & (~FWPS_RIGHT_ACTION_WRITE);classifyOut->flags = classifyOut->flags | FWPS_CLASSIFY_OUT_FLAG_ABSORB;}else if (strcmp(szRemotePort, "0") == 0){DbgPrint("[LyShark.com] 拦截Ping访问请求 --> %s \n", szRemoteAddress);// 设置拒绝规则 拒绝连接classifyOut->actionType = FWP_ACTION_BLOCK;classifyOut->rights = classifyOut->rights & (~FWPS_RIGHT_ACTION_WRITE);classifyOut->flags = classifyOut->flags | FWPS_CLASSIFY_OUT_FLAG_ABSORB;}// 显示DbgPrint("[LyShark.com] 方向: %d -> 协议类型: %s -> 本端地址: %u.%u.%u.%u:%d -> 对端地址: %u.%u.%u.%u:%d -> IRQL: %d -> 进程ID: %I64d -> 路径: %S \n",wDirection,szProtocalName,(ulLocalIp >> 24) & 0xFF,(ulLocalIp >> 16) & 0xFF,(ulLocalIp >> 8) & 0xFF,(ulLocalIp)& 0xFF,uLocalPort,(ulRemoteIp >> 24) & 0xFF,(ulRemoteIp >> 16) & 0xFF,(ulRemoteIp >> 8) & 0xFF,(ulRemoteIp)& 0xFF,uRemotePort,kCurrentIrql,processId,(PWCHAR)szProcessPath);}// Callout函数 notifyFn 事后回调函数
NTSTATUS NTAPI notifyFn(_In_ FWPS_CALLOUT_NOTIFY_TYPE notifyType, _In_ const GUID* filterKey, _Inout_ FWPS_FILTER2* filter)
{NTSTATUS status = STATUS_SUCCESS;return status;
}// Callout函数 flowDeleteFn 事后回调函数
VOID NTAPI flowDeleteFn(_In_ UINT16 layerId, _In_ UINT32 calloutId, _In_ UINT64 flowContext)
{return;
}// 默认派遣函数
NTSTATUS DriverDefaultHandle(PDEVICE_OBJECT pDevObj, PIRP pIrp)
{NTSTATUS status = STATUS_SUCCESS;pIrp->IoStatus.Status = status;pIrp->IoStatus.Information = 0;IoCompleteRequest(pIrp, IO_NO_INCREMENT);return status;
}// 创建设备
NTSTATUS CreateDevice(PDRIVER_OBJECT pDriverObject)
{NTSTATUS status = STATUS_SUCCESS;PDEVICE_OBJECT pDevObj = NULL;UNICODE_STRING ustrDevName, ustrSymName;RtlInitUnicodeString(&ustrDevName, DEV_NAME);RtlInitUnicodeString(&ustrSymName, SYM_NAME);status = IoCreateDevice(pDriverObject, 0, &ustrDevName, FILE_DEVICE_NETWORK, 0, FALSE, &pDevObj);if (!NT_SUCCESS(status)){return status;}status = IoCreateSymbolicLink(&ustrSymName, &ustrDevName);if (!NT_SUCCESS(status)){return status;}return status;
}// 卸载驱动
VOID UnDriver(PDRIVER_OBJECT driver)
{// 删除回调函数和过滤器,关闭引擎WfpUnload();UNICODE_STRING ustrSymName;RtlInitUnicodeString(&ustrSymName, SYM_NAME);IoDeleteSymbolicLink(&ustrSymName);if (driver->DeviceObject){IoDeleteDevice(driver->DeviceObject);}
}// 驱动入口
NTSTATUS DriverEntry(IN PDRIVER_OBJECT Driver, PUNICODE_STRING RegistryPath)
{NTSTATUS status = STATUS_SUCCESS;Driver->DriverUnload = UnDriver;for (ULONG i = 0; i < IRP_MJ_MAXIMUM_FUNCTION; i++){Driver->MajorFunction[i] = DriverDefaultHandle;}// 创建设备CreateDevice(Driver);// 启动WFPWfpLoad(Driver->DeviceObject);Driver->DriverUnload = UnDriver;return STATUS_SUCCESS;
}

上方代码是一个最基本的WFP过滤框架头部函数，声明部分来源于微软的定义此处不做解释，需要注意GUID_ALE_AUTH_CONNECT_CALLOUT_V4代表的是一个随机UUID值，该值可以任意定义只要不一致即可，驱动程序运行后会率先执行WfpLoad()这个函数，该函数内部通过RegisterCalloutForLayer()注册了一个过滤点，此处我们必须要注意三个回调函数，classifyFn, notifyFn, flowDeleteFn 他们分别的功能时，事前回调，事后回调，事后回调，而WFP框架中我们最需要注意的也就是对这三个函数进行重定义，也就是需要重写函数来实现我们特定的功能。

NTSTATUS RegisterCalloutForLayer
(IN const GUID* layerKey,IN const GUID* calloutKey,IN FWPS_CALLOUT_CLASSIFY_FN classifyFn,IN FWPS_CALLOUT_NOTIFY_FN notifyFn,IN FWPS_CALLOUT_FLOW_DELETE_NOTIFY_FN flowDeleteNotifyFn,OUT UINT32* calloutId,OUT UINT64* filterId
}

既然是防火墙那么必然classifyFn事前更重要一些，如果需要监控网络流量则需要在事前函数中做处理，而如果是监视则可以在事后做处理，既然要在事前进行处理，那么我们就来看看事前是如何处理的流量。

// Callout函数 classifyFn 事前回调函数
VOID NTAPI classifyFn(_In_ const FWPS_INCOMING_VALUES0* inFixedValues, _In_ const FWPS_INCOMING_METADATA_VALUES0* inMetaValues, _Inout_opt_ void* layerData, _In_opt_ const void* classifyContext, _In_ const FWPS_FILTER2* filter, _In_ UINT64 flowContext, _Inout_ FWPS_CLASSIFY_OUT0* classifyOut)
{// 数据包的方向,取值 FWP_DIRECTION_INBOUND = 1 或 FWP_DIRECTION_OUTBOUND = 0WORD wDirection = inFixedValues->incomingValue[FWPS_FIELD_ALE_FLOW_ESTABLISHED_V4_DIRECTION].value.int8;// 定义本机地址与本机端口ULONG ulLocalIp = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_LOCAL_ADDRESS].value.uint32;UINT16 uLocalPort = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_LOCAL_PORT].value.uint16;// 定义对端地址与对端端口ULONG ulRemoteIp = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_REMOTE_ADDRESS].value.uint32;UINT16 uRemotePort = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_REMOTE_PORT].value.uint16;// 获取当前进程IRQKIRQL kCurrentIrql = KeGetCurrentIrql();// 获取进程IDULONG64 processId = inMetaValues->processId;UCHAR szProcessPath[256] = { 0 };CHAR szProtocalName[256] = { 0 };RtlZeroMemory(szProcessPath, 256);// 获取进程路径for (ULONG i = 0; i < inMetaValues->processPath->size; i++){// 里面是宽字符存储的szProcessPath[i] = inMetaValues->processPath->data[i];}// 获取当前协议类型ProtocalIdToName(inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_PROTOCOL].value.uint16, szProtocalName);// 设置默认规则 允许连接classifyOut->actionType = FWP_ACTION_PERMIT;// 禁止指定进程网络连接if (NULL != wcsstr((PWCHAR)szProcessPath, L"qq.exe")){// 设置拒绝规则 拒绝连接classifyOut->actionType = FWP_ACTION_BLOCK;classifyOut->rights = classifyOut->rights & (~FWPS_RIGHT_ACTION_WRITE);classifyOut->flags = classifyOut->flags | FWPS_CLASSIFY_OUT_FLAG_ABSORB;}// 输出对端地址字符串 并阻断链接char szRemoteAddress[256] = { 0 };char szRemotePort[128] = { 0 };char szLocalAddress[256] = { 0 };char szLocalPort[128] = { 0 };sprintf(szRemoteAddress, "%u.%u.%u.%u", (ulRemoteIp >> 24) & 0xFF, (ulRemoteIp >> 16) & 0xFF, (ulRemoteIp >> 8) & 0xFF, (ulRemoteIp)& 0xFF);sprintf(szRemotePort, "%d", uRemotePort);sprintf(szLocalAddress, "%u.%u.%u.%u", (ulLocalIp >> 24) & 0xFF, (ulLocalIp >> 16) & 0xFF, (ulLocalIp >> 8) & 0xFF, (ulLocalIp)& 0xFF);sprintf(szLocalPort, "%d", uLocalPort);// DbgPrint("本端: %s : %s --> 对端: %s : %s \n", szLocalAddress, szLocalPort, szRemoteAddress, szRemotePort);// 如果对端地址是 8.141.58.64 且对端端口是 443 则拒绝连接if (strcmp(szRemoteAddress, "8.141.58.64") == 0 && strcmp(szRemotePort, "443") == 0){DbgPrint("拦截网站访问请求 --> %s : %s \n", szRemoteAddress, szRemotePort);// 设置拒绝规则 拒绝连接classifyOut->actionType = FWP_ACTION_BLOCK;classifyOut->rights = classifyOut->rights & (~FWPS_RIGHT_ACTION_WRITE);classifyOut->flags = classifyOut->flags | FWPS_CLASSIFY_OUT_FLAG_ABSORB;}else if (strcmp(szRemotePort, "0") == 0){DbgPrint("拦截Ping访问请求 --> %s \n", szRemoteAddress);// 设置拒绝规则 拒绝连接classifyOut->actionType = FWP_ACTION_BLOCK;classifyOut->rights = classifyOut->rights & (~FWPS_RIGHT_ACTION_WRITE);classifyOut->flags = classifyOut->flags | FWPS_CLASSIFY_OUT_FLAG_ABSORB;}/*// 显示DbgPrint("方向: %d -> 协议类型: %s -> 本端地址: %u.%u.%u.%u:%d -> 对端地址: %u.%u.%u.%u:%d -> IRQL: %d -> 进程ID: %I64d -> 路径: %S \n",wDirection,szProtocalName,(ulLocalIp >> 24) & 0xFF,(ulLocalIp >> 16) & 0xFF,(ulLocalIp >> 8) & 0xFF,(ulLocalIp)& 0xFF,uLocalPort,(ulRemoteIp >> 24) & 0xFF,(ulRemoteIp >> 16) & 0xFF,(ulRemoteIp >> 8) & 0xFF,(ulRemoteIp)& 0xFF,uRemotePort,kCurrentIrql,processId,(PWCHAR)szProcessPath);*/
}

当有新的网络数据包路由到事前函数时，程序中会通过如下案例直接得到我们所需要的数据包头，ProtocalIdToName函数则是一个将特定类型数字转为字符串的转换函数。

// 数据包的方向,取值 FWP_DIRECTION_INBOUND = 1 或 FWP_DIRECTION_OUTBOUND = 0
WORD wDirection = inFixedValues->incomingValue[FWPS_FIELD_ALE_FLOW_ESTABLISHED_V4_DIRECTION].value.int8;// 定义本机地址与本机端口
ULONG ulLocalIp = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_LOCAL_ADDRESS].value.uint32;
UINT16 uLocalPort = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_LOCAL_PORT].value.uint16;// 定义对端地址与对端端口
ULONG ulRemoteIp = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_REMOTE_ADDRESS].value.uint32;
UINT16 uRemotePort = inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_REMOTE_PORT].value.uint16;// 获取当前进程IRQ
KIRQL kCurrentIrql = KeGetCurrentIrql();// 获取进程ID
ULONG64 processId = inMetaValues->processId;
UCHAR szProcessPath[256] = { 0 };
CHAR szProtocalName[256] = { 0 };
RtlZeroMemory(szProcessPath, 256);// 获取进程路径
for (ULONG i = 0; i < inMetaValues->processPath->size; i++)
{// 里面是宽字符存储的szProcessPath[i] = inMetaValues->processPath->data[i];
}// 获取当前协议类型
ProtocalIdToName(inFixedValues->incomingValue[FWPS_FIELD_ALE_AUTH_CONNECT_V4_IP_PROTOCOL].value.uint16, szProtocalName);

拦截浏览器上网： 防火墙的默认规则我们将其改为放行所有classifyOut->actionType = FWP_ACTION_PERMIT;，当我们需要拦截特定进程上网时则只需要判断调用原，如果时特定进程则直接设置拒绝网络访问。

// 设置默认规则 允许连接
classifyOut->actionType = FWP_ACTION_PERMIT;// 禁止指定进程网络连接
if (NULL != wcsstr((PWCHAR)szProcessPath, L"iexplore.exe"))
{// 设置拒绝规则 拒绝连接classifyOut->actionType = FWP_ACTION_BLOCK;classifyOut->rights = classifyOut->rights & (~FWPS_RIGHT_ACTION_WRITE);classifyOut->flags = classifyOut->flags | FWPS_CLASSIFY_OUT_FLAG_ABSORB;DbgPrint("[LyShark.com] 拦截IE网络链接请求... \n");
}

当这段驱动程序被加载后，则用户使用IE访问任何页面都将提示无法访问。

拦截指定IP地址： 防火墙的另一个重要功能就是拦截主机自身访问特定网段，此功能只需要增加过滤条件即可实现，如下当用户访问8.141.58.64这个IP地址是则会被拦截，如果监测到用户时Ping请求则也会被拦截。

// 如果对端地址是 8.141.58.64 且对端端口是 443 则拒绝连接
if (strcmp(szRemoteAddress, "8.141.58.64") == 0 && strcmp(szRemotePort, "443") == 0)
{DbgPrint("拦截网站访问请求 --> %s : %s \n", szRemoteAddress, szRemotePort);// 设置拒绝规则 拒绝连接classifyOut->actionType = FWP_ACTION_BLOCK;classifyOut->rights = classifyOut->rights & (~FWPS_RIGHT_ACTION_WRITE);classifyOut->flags = classifyOut->flags | FWPS_CLASSIFY_OUT_FLAG_ABSORB;
}
else if (strcmp(szRemotePort, "0") == 0)
{DbgPrint("拦截Ping访问请求 --> %s \n", szRemoteAddress);// 设置拒绝规则 拒绝连接classifyOut->actionType = FWP_ACTION_BLOCK;classifyOut->rights = classifyOut->rights & (~FWPS_RIGHT_ACTION_WRITE);classifyOut->flags = classifyOut->flags | FWPS_CLASSIFY_OUT_FLAG_ABSORB;
}

当这段驱动程序被加载后，则用户主机无法访问8.141.58.64且无法使用ping命令。

抓取底层数据包： 如果仅仅只是想要输出流经自身主机的数据包，则只需要对特定数据包进行解码即可得到原始数据。

// 输出对端地址字符串 并阻断链接
char szRemoteAddress[256] = { 0 };
char szRemotePort[128] = { 0 };char szLocalAddress[256] = { 0 };
char szLocalPort[128] = { 0 };sprintf(szRemoteAddress, "%u.%u.%u.%u", (ulRemoteIp >> 24) & 0xFF, (ulRemoteIp >> 16) & 0xFF, (ulRemoteIp >> 8) & 0xFF, (ulRemoteIp)& 0xFF);
sprintf(szRemotePort, "%d", uRemotePort);sprintf(szLocalAddress, "%u.%u.%u.%u", (ulLocalIp >> 24) & 0xFF, (ulLocalIp >> 16) & 0xFF, (ulLocalIp >> 8) & 0xFF, (ulLocalIp)& 0xFF);
sprintf(szLocalPort, "%d", uLocalPort);// 显示
DbgPrint("[LyShark.com] 方向: %d -> 协议类型: %s -> 本端地址: %u.%u.%u.%u:%d -> 对端地址: %u.%u.%u.%u:%d -> IRQL: %d -> 进程ID: %I64d -> 路径: %S \n",
wDirection,
szProtocalName,
(ulLocalIp >> 24) & 0xFF,
(ulLocalIp >> 16) & 0xFF,
(ulLocalIp >> 8) & 0xFF,
(ulLocalIp)& 0xFF,
uLocalPort,
(ulRemoteIp >> 24) & 0xFF,
(ulRemoteIp >> 16) & 0xFF,
(ulRemoteIp >> 8) & 0xFF,
(ulRemoteIp)& 0xFF,
uRemotePort,
kCurrentIrql,
processId,
(PWCHAR)szProcessPath);

当这段驱动程序被加载后，则用户可看到流经本机的所有数据包。