1 files changed, 149 insertions, 0 deletions
diff --git a/api/driver.c b/api/driver.c
new file mode 100644
index 0000000..b6bf11c
--- /dev/null
+++ b/api/driver.c
@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2018-2020 WireGuard LLC. All Rights Reserved.
+ */
+
+#include "pch.h"
+
+/**
+ * Retrieves driver information detail for a device information set or a particular device information element in the
+ * device information set.
+ *
+ * @param DevInfo       A handle to the device information set that contains a device information element that
+ *                      represents the device for which to retrieve driver information.
+ *
+ * @param DevInfoData   A pointer to a structure that specifies the device information element in DevInfo.
+ *
+ * @param DrvInfoData   A pointer to a structure that specifies the driver information element that represents the
+ *                      driver for which to retrieve details.
+ *
+ * @param DrvInfoDetailData  A pointer to a structure that receives detailed information about the specified driver.
+ *                      Must be released with HeapFree(GetProcessHeap(), 0, *DrvInfoDetailData) after use.
+ *
+ * @return non-zero on success; zero otherwise - use GetLastError().
+ */
+_Return_type_success_(return != NULL) SP_DRVINFO_DETAIL_DATA_W *DriverGetDrvInfoDetail(
+    _In_ HDEVINFO DevInfo,
+    _In_opt_ SP_DEVINFO_DATA *DevInfoData,
+    _In_ SP_DRVINFO_DATA_W *DrvInfoData)
+{
+    HANDLE Heap = GetProcessHeap();
+    DWORD Size = sizeof(SP_DRVINFO_DETAIL_DATA_W) + 0x100;
+    DWORD Result;
+    for (;;)
+    {
+        SP_DRVINFO_DETAIL_DATA_W *DrvInfoDetailData = HeapAlloc(Heap, 0, Size);
+        if (!DrvInfoDetailData)
+        {
+            Result = ERROR_OUTOFMEMORY;
+            goto out;
+        }
+        DrvInfoDetailData->cbSize = sizeof(SP_DRVINFO_DETAIL_DATA_W);
+        if (SetupDiGetDriverInfoDetailW(DevInfo, DevInfoData, DrvInfoData, DrvInfoDetailData, Size, &Size))
+            return DrvInfoDetailData;
+        Result = GetLastError();
+        HeapFree(Heap, 0, DrvInfoDetailData);
+        if (Result != ERROR_INSUFFICIENT_BUFFER)
+        {
+            WINTUN_LOGGER_ERROR(L"Failed", Result);
+            goto out;
+        }
+    }
+out:
+    SetLastError(Result);
+    return NULL;
+}
+
+/**
+ * Checks if the device (i.e. network adapter) is using Wintun driver.
+ *
+ * @param DevInfo       A handle to the device information set that contains a device information element that
+ *                      represents the device.
+ *
+ * @param DevInfoData   A pointer to a structure that specifies the device information element in DevInfo.
+ *
+ * @return non-zero when using Wintun driver; zero when not or error - use GetLastError().
+ */
+BOOL
+DriverIsWintunAdapter(_In_ HDEVINFO DevInfo, _In_opt_ SP_DEVINFO_DATA *DevInfoData)
+{
+    BOOL Found = FALSE;
+    if (!SetupDiBuildDriverInfoList(DevInfo, DevInfoData, SPDIT_COMPATDRIVER))
+    {
+        WINTUN_LOGGER_LAST_ERROR(L"Failed to build list of drivers");
+        return FALSE;
+    }
+    HANDLE Heap = GetProcessHeap();
+    for (DWORD EnumIndex = 0; !Found; ++EnumIndex)
+    {
+        SP_DRVINFO_DATA_W DrvInfoData = { .cbSize = sizeof(SP_DRVINFO_DATA_W) };
+        if (!SetupDiEnumDriverInfoW(DevInfo, DevInfoData, SPDIT_COMPATDRIVER, EnumIndex, &DrvInfoData))
+        {
+            if (GetLastError() == ERROR_NO_MORE_ITEMS)
+                break;
+            continue;
+        }
+        SP_DRVINFO_DETAIL_DATA_W *DrvInfoDetailData = DriverGetDrvInfoDetail(DevInfo, DevInfoData, &DrvInfoData);
+        if (!DrvInfoDetailData)
+            continue;
+        Found = !_wcsicmp(DrvInfoDetailData->HardwareID, L"wintun");
+        HeapFree(Heap, 0, DrvInfoDetailData);
+    }
+    SetupDiDestroyDriverInfoList(DevInfo, DevInfoData, SPDIT_COMPATDRIVER);
+    SetLastError(ERROR_SUCCESS);
+    return Found;
+}
+
+/**
+ * Returns a handle to the adapter device object.
+ *
+ * @param InstanceId    Adapter device instance ID.
+ *
+ * @return device handle on success; INVALID_HANDLE_VALUE otherwise - use GetLastError().
+ */
+_Return_type_success_(return != INVALID_HANDLE_VALUE) HANDLE
+    DriverGetAdapterDeviceObject(_In_opt_z_ const WCHAR *InstanceId)
+{
+    HANDLE Heap = GetProcessHeap();
+    ULONG InterfacesLen;
+    HANDLE Handle = INVALID_HANDLE_VALUE;
+    DWORD Result = CM_Get_Device_Interface_List_SizeW(
+        &InterfacesLen, (GUID *)&GUID_DEVINTERFACE_NET, (DEVINSTID_W)InstanceId, CM_GET_DEVICE_INTERFACE_LIST_PRESENT);
+    if (Result != CR_SUCCESS)
+    {
+        WINTUN_LOGGER(WINTUN_LOG_ERR, L"Failed to get device associated device instances size");
+        SetLastError(ERROR_GEN_FAILURE);
+        return INVALID_HANDLE_VALUE;
+    }
+    WCHAR *Interfaces = HeapAlloc(Heap, 0, InterfacesLen * sizeof(WCHAR));
+    if (!Interfaces)
+    {
+        SetLastError(ERROR_OUTOFMEMORY);
+        return INVALID_HANDLE_VALUE;
+    }
+    Result = CM_Get_Device_Interface_ListW(
+        (GUID *)&GUID_DEVINTERFACE_NET,
+        (DEVINSTID_W)InstanceId,
+        Interfaces,
+        InterfacesLen,
+        CM_GET_DEVICE_INTERFACE_LIST_PRESENT);
+    if (Result != CR_SUCCESS)
+    {
+        WINTUN_LOGGER(WINTUN_LOG_ERR, L"Failed to get device associated device instances");
+        Result = ERROR_GEN_FAILURE;
+        goto cleanupBuf;
+    }
+    Handle = CreateFileW(
+        Interfaces,
+        GENERIC_READ | GENERIC_WRITE,
+        FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+        NULL,
+        OPEN_EXISTING,
+        0,
+        NULL);
+    Result = Handle != INVALID_HANDLE_VALUE ? ERROR_SUCCESS : WINTUN_LOGGER_LAST_ERROR(L"Failed to connect to device");
+cleanupBuf:
+    HeapFree(Heap, 0, Interfaces);
+    SetLastError(Result);
+    return Handle;
+}