int main() {
HMODULE hNsi = LoadLibraryW(L"Nsi.dll");
NsiGetParameterProc _NsiGetParameter = (NsiGetParameterProc)GetProcAddress(hNsi, "NsiGetParameter");
// Declare and initialize variables
PIP_INTERFACE_INFO pInfo = NULL;
ULONG ulOutBufLen = 0;
DWORD dwRetVal = 0;
int iReturn = 1;
int i;
// Make an initial call to GetInterfaceInfo to get
// the necessary size in the ulOutBufLen variable
dwRetVal = GetInterfaceInfo(NULL, &ulOutBufLen);
if (dwRetVal == ERROR_INSUFFICIENT_BUFFER) {
pInfo = (IP_INTERFACE_INFO *)MALLOC(ulOutBufLen);
if (pInfo == NULL) {
printf
("Unable to allocate memory needed to call GetInterfaceInfo\n");
return 1;
}
}
// Make a second call to GetInterfaceInfo to get
// the actual data we need
dwRetVal = GetInterfaceInfo(pInfo, &ulOutBufLen);
if (dwRetVal == NO_ERROR) {
printf("Number of Adapters: %ld\n\n", pInfo->NumAdapters);
for (i = 0; i < pInfo->NumAdapters; i++) {
printf("Adapter Index[%d]: %ld\n", i,
pInfo->Adapter[i].Index);
NET_LUID Luid;
NETIO_STATUS st = ConvertInterfaceIndexToLuid(pInfo->Adapter[i].Index, &Luid);
if (st == NO_ERROR) {
BYTE OutputBuffer[0xB8] = { /* zero padding */ };
DWORD nsi_st = _NsiGetParameter(1, NPI_MS_IPV4_MODULEID, 7, &Luid, sizeof(Luid), 0, OutputBuffer, sizeof(OutputBuffer), 0);
if (nsi_st == NO_ERROR) {
PrintHex(OutputBuffer, sizeof(OutputBuffer));
}
}
}
iReturn = 0;
}
else if (dwRetVal == ERROR_NO_DATA) {
printf
("There are no network adapters with IPv4 enabled on the local system\n");
iReturn = 0;
}
else {
printf("GetInterfaceInfo failed with error: %d\n", dwRetVal);
iReturn = 1;
}
FREE(pInfo);
return (iReturn);
}
int uv_if_indextoname(unsigned int ifindex, char* buffer, size_t* size) {
NET_LUID luid;
wchar_t wname[NDIS_IF_MAX_STRING_SIZE + 1]; /* Add one for the NUL. */
DWORD bufsize;
int r;
if (buffer == NULL || size == NULL || *size == 0)
return UV_EINVAL;
r = ConvertInterfaceIndexToLuid(ifindex, &luid);
if (r != 0)
return uv_translate_sys_error(r);
r = ConvertInterfaceLuidToNameW(&luid, wname, ARRAY_SIZE(wname));
if (r != 0)
return uv_translate_sys_error(r);
/* Check how much space we need */
bufsize = WideCharToMultiByte(CP_UTF8, 0, wname, -1, NULL, 0, NULL, NULL);
if (bufsize == 0) {
return uv_translate_sys_error(GetLastError());
} else if (bufsize > *size) {
*size = bufsize;
return UV_ENOBUFS;
}
/* Convert to UTF-8 */
bufsize = WideCharToMultiByte(CP_UTF8,
0,
wname,
-1,
buffer,
*size,
NULL,
NULL);
if (bufsize == 0)
return uv_translate_sys_error(GetLastError());
*size = bufsize - 1;
return 0;
}
/******************************************************************************
PacketFilter::StartFirewall - This public method starts firewall.
*******************************************************************************/
BOOL PacketFilter::StartFirewall()
{
BOOL bStarted = FALSE;
NET_LUID tapluid;
PIP_ADAPTER_INFO pAdapterInfo;
PIP_ADAPTER_INFO pAdapter = NULL;
DWORD dwRetVal = 0;
ULONG ulOutBufLen = sizeof(IP_ADAPTER_INFO);
pAdapterInfo = (IP_ADAPTER_INFO *)MALLOC(sizeof(IP_ADAPTER_INFO));
if (pAdapterInfo == NULL) {
printf("Error allocating memory needed to call GetAdaptersinfo\n");
return 1;
}
// Make an initial call to GetAdaptersInfo to get
// the necessary size into the ulOutBufLen variable
if (GetAdaptersInfo(pAdapterInfo, &ulOutBufLen) == ERROR_BUFFER_OVERFLOW) {
FREE(pAdapterInfo);
pAdapterInfo = (IP_ADAPTER_INFO *)MALLOC(ulOutBufLen);
if (pAdapterInfo == NULL) {
printf("Error allocating memory needed to call GetAdaptersinfo\n");
return 2;
}
}
if ((dwRetVal = GetAdaptersInfo(pAdapterInfo, &ulOutBufLen)) == NO_ERROR) {
pAdapter = pAdapterInfo;
while (pAdapter) {
if ((strstr(pAdapter->Description, "TAP-Windows Adapter V9") != NULL) ||
(strstr(pAdapter->Description, "Viscosity Virtual Adapter") != NULL))
{
if (ConvertInterfaceIndexToLuid(pAdapter->Index, &tapluid) == NO_ERROR)
tapluids.push_back(tapluid.Value);
}
pAdapter = pAdapter->Next;
}
}
else {
printf("GetAdaptersInfo failed with error: %d\n", dwRetVal);
}
if (pAdapterInfo)
FREE(pAdapterInfo);
if (tapluids.size() <= 0) {
printf("No TAP adapters found!\n");
return 3;
}
printf("Found %d TAP adapters\n", tapluids.size());
try
{
// Create packet filter interface.
printf("before CreateDeleteInterface()\n");
if( ERROR_SUCCESS == CreateDeleteInterface(true) )
{
printf("before BindUnbindInterface()\n");
// Bind to packet filter interface.
if( ERROR_SUCCESS == BindUnbindInterface(true) )
{
printf("before AddRemoveFilter()\n");
// Add filters.
AddRemoveFilter(true);
bStarted = TRUE;
}
}
}
catch(...)
{
printf("catch ...\n");
}
return bStarted;
}
/******************************************************************************
PacketFilter::StartFirewall - This public method starts firewall.
*******************************************************************************/
BOOL PacketFilter::StartFirewall()
{
BOOL bStarted = FALSE;
int tapadapter_index = -1;
PIP_ADAPTER_INFO pAdapterInfo;
PIP_ADAPTER_INFO pAdapter = NULL;
DWORD dwRetVal = 0;
ULONG ulOutBufLen = sizeof(IP_ADAPTER_INFO);
pAdapterInfo = (IP_ADAPTER_INFO *)MALLOC(sizeof(IP_ADAPTER_INFO));
if (pAdapterInfo == NULL) {
printf("Error allocating memory needed to call GetAdaptersinfo\n");
return 1;
}
// Make an initial call to GetAdaptersInfo to get
// the necessary size into the ulOutBufLen variable
if (GetAdaptersInfo(pAdapterInfo, &ulOutBufLen) == ERROR_BUFFER_OVERFLOW) {
FREE(pAdapterInfo);
pAdapterInfo = (IP_ADAPTER_INFO *)MALLOC(ulOutBufLen);
if (pAdapterInfo == NULL) {
printf("Error allocating memory needed to call GetAdaptersinfo\n");
return 2;
}
}
if ((dwRetVal = GetAdaptersInfo(pAdapterInfo, &ulOutBufLen)) == NO_ERROR) {
pAdapter = pAdapterInfo;
while (pAdapter) {
if (strcmp(pAdapter->Description, "TAP-Windows Adapter V9") == 0) {
tapadapter_index = pAdapter->Index;
break;
}
pAdapter = pAdapter->Next;
}
}
else {
printf("GetAdaptersInfo failed with error: %d\n", dwRetVal);
}
if (pAdapterInfo)
FREE(pAdapterInfo);
NET_LUID tapluid;
if (tapadapter_index < 0) {
printf("Tap Adapter not found!\n");
return 3;
}
if (ConvertInterfaceIndexToLuid(tapadapter_index, &tapluid) != NO_ERROR) {
printf("Cant find LUID for TAP adapter!\n");
return 4;
}
this->tapluid64 = tapluid.Value;
try
{
// Create packet filter interface.
if( ERROR_SUCCESS == CreateDeleteInterface( true ) )
{
// Bind to packet filter interface.
if( ERROR_SUCCESS == BindUnbindInterface( true ) )
{
// Add filters.
AddRemoveFilter( true );
bStarted = TRUE;
}
}
}
catch(...)
{
}
return bStarted;
}
DWORD
add_block_dns_filters(HANDLE *engine_handle,
int index,
const WCHAR *exe_path,
block_dns_msg_handler_t msg_handler
)
{
FWPM_SESSION0 session = {0};
FWPM_SUBLAYER0 *sublayer_ptr = NULL;
NET_LUID tapluid;
UINT64 filterid;
FWP_BYTE_BLOB *openvpnblob = NULL;
FWPM_FILTER0 Filter = {0};
FWPM_FILTER_CONDITION0 Condition[2] = {0};
DWORD err = 0;
if (!msg_handler)
{
msg_handler = default_msg_handler;
}
/* Add temporary filters which don't survive reboots or crashes. */
session.flags = FWPM_SESSION_FLAG_DYNAMIC;
*engine_handle = NULL;
err = FwpmEngineOpen0(NULL, RPC_C_AUTHN_WINNT, NULL, &session, engine_handle);
CHECK_ERROR(err, "FwpEngineOpen: open fwp session failed");
msg_handler(0, "Block_DNS: WFP engine opened");
/* Check sublayer exists and add one if it does not. */
if (FwpmSubLayerGetByKey0(*engine_handle, &OPENVPN_BLOCK_OUTSIDE_DNS_SUBLAYER, &sublayer_ptr)
== ERROR_SUCCESS)
{
msg_handler(0, "Block_DNS: Using existing sublayer");
FwpmFreeMemory0((void **)&sublayer_ptr);
}
else
{ /* Add a new sublayer -- as another process may add it in the meantime,
* do not treat "already exists" as an error */
err = add_sublayer(OPENVPN_BLOCK_OUTSIDE_DNS_SUBLAYER);
if (err == FWP_E_ALREADY_EXISTS || err == ERROR_SUCCESS)
{
msg_handler(0, "Block_DNS: Added a persistent sublayer with pre-defined UUID");
}
else
{
CHECK_ERROR(err, "add_sublayer: failed to add persistent sublayer");
}
}
err = ConvertInterfaceIndexToLuid(index, &tapluid);
CHECK_ERROR(err, "Convert interface index to luid failed");
err = FwpmGetAppIdFromFileName0(exe_path, &openvpnblob);
CHECK_ERROR(err, "Get byte blob for openvpn executable name failed");
/* Prepare filter. */
Filter.subLayerKey = OPENVPN_BLOCK_OUTSIDE_DNS_SUBLAYER;
Filter.displayData.name = FIREWALL_NAME;
Filter.weight.type = FWP_UINT8;
Filter.weight.uint8 = 0xF;
Filter.filterCondition = Condition;
Filter.numFilterConditions = 2;
/* First filter. Permit IPv4 DNS queries from OpenVPN itself. */
Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V4;
Filter.action.type = FWP_ACTION_PERMIT;
Condition[0].fieldKey = FWPM_CONDITION_IP_REMOTE_PORT;
Condition[0].matchType = FWP_MATCH_EQUAL;
Condition[0].conditionValue.type = FWP_UINT16;
Condition[0].conditionValue.uint16 = 53;
Condition[1].fieldKey = FWPM_CONDITION_ALE_APP_ID;
Condition[1].matchType = FWP_MATCH_EQUAL;
Condition[1].conditionValue.type = FWP_BYTE_BLOB_TYPE;
Condition[1].conditionValue.byteBlob = openvpnblob;
err = FwpmFilterAdd0(*engine_handle, &Filter, NULL, &filterid);
CHECK_ERROR(err, "Add filter to permit IPv4 port 53 traffic from OpenVPN failed");
/* Second filter. Permit IPv6 DNS queries from OpenVPN itself. */
Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V6;
err = FwpmFilterAdd0(*engine_handle, &Filter, NULL, &filterid);
CHECK_ERROR(err, "Add filter to permit IPv6 port 53 traffic from OpenVPN failed");
msg_handler(0, "Block_DNS: Added permit filters for exe_path");
/* Third filter. Block all IPv4 DNS queries. */
Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V4;
Filter.action.type = FWP_ACTION_BLOCK;
Filter.weight.type = FWP_EMPTY;
Filter.numFilterConditions = 1;
err = FwpmFilterAdd0(*engine_handle, &Filter, NULL, &filterid);
CHECK_ERROR(err, "Add filter to block IPv4 DNS traffic failed");
/* Forth filter. Block all IPv6 DNS queries. */
Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V6;
err = FwpmFilterAdd0(*engine_handle, &Filter, NULL, &filterid);
CHECK_ERROR(err, "Add filter to block IPv6 DNS traffic failed");
msg_handler(0, "Block_DNS: Added block filters for all interfaces");
/* Fifth filter. Permit IPv4 DNS queries from TAP.
* Use a non-zero weight so that the permit filters get higher priority
* over the block filter added with automatic weighting */
Filter.weight.type = FWP_UINT8;
Filter.weight.uint8 = 0xE;
Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V4;
Filter.action.type = FWP_ACTION_PERMIT;
Filter.numFilterConditions = 2;
Condition[1].fieldKey = FWPM_CONDITION_IP_LOCAL_INTERFACE;
Condition[1].matchType = FWP_MATCH_EQUAL;
Condition[1].conditionValue.type = FWP_UINT64;
Condition[1].conditionValue.uint64 = &tapluid.Value;
err = FwpmFilterAdd0(*engine_handle, &Filter, NULL, &filterid);
CHECK_ERROR(err, "Add filter to permit IPv4 DNS traffic through TAP failed");
/* Sixth filter. Permit IPv6 DNS queries from TAP.
* Use same weight as IPv4 filter */
Filter.layerKey = FWPM_LAYER_ALE_AUTH_CONNECT_V6;
err = FwpmFilterAdd0(*engine_handle, &Filter, NULL, &filterid);
CHECK_ERROR(err, "Add filter to permit IPv6 DNS traffic through TAP failed");
msg_handler(0, "Block_DNS: Added permit filters for TAP interface");
out:
if (openvpnblob)
{
FwpmFreeMemory0((void **)&openvpnblob);
}
if (err && *engine_handle)
{
FwpmEngineClose0(*engine_handle);
*engine_handle = NULL;
}
return err;
}