/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * (c) ZeroTier, Inc.
 * https://www.zerotier.com/
 */

#include "WindowsEthernetTap.hpp"

#include "../node/Constants.hpp"
#include "../node/Mutex.hpp"
#include "../node/Utils.hpp"
#include "..\windows\TapDriver6\tap-windows.h"
#include "OSUtils.hpp"
#include "WinDNSHelper.hpp"

#include <IPHlpApi.h>
#include <SetupAPI.h>
#include <atlbase.h>
#include <cfgmgr32.h>
#include <iostream>
#include <malloc.h>
#include <netcon.h>
#include <netioapi.h>
#include <netlistmgr.h>
#include <newdev.h>
#include <nldef.h>
#include <set>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <tchar.h>
#include <wchar.h>
#include <windows.h>
#include <winreg.h>
#include <winsock2.h>
#include <ws2ipdef.h>
#include <ws2tcpip.h>

// Create a fake unused default route to force detection of network type on networks without gateways
#define ZT_WINDOWS_CREATE_FAKE_DEFAULT_ROUTE

// Function signatures of dynamically loaded functions, from newdev.h, setupapi.h, and cfgmgr32.h
typedef BOOL(WINAPI* UpdateDriverForPlugAndPlayDevicesA_t)(_In_opt_ HWND hwndParent, _In_ LPCSTR HardwareId, _In_ LPCSTR FullInfPath, _In_ DWORD InstallFlags, _Out_opt_ PBOOL bRebootRequired);
typedef BOOL(WINAPI* SetupDiGetINFClassA_t)(_In_ PCSTR InfName, _Out_ LPGUID ClassGuid, _Out_writes_(ClassNameSize) PSTR ClassName, _In_ DWORD ClassNameSize, _Out_opt_ PDWORD RequiredSize);
typedef HDEVINFO(WINAPI* SetupDiCreateDeviceInfoList_t)(_In_opt_ CONST GUID* ClassGuid, _In_opt_ HWND hwndParent);
typedef BOOL(WINAPI* SetupDiCreateDeviceInfoA_t)(
	_In_ HDEVINFO DeviceInfoSet,
	_In_ PCSTR DeviceName,
	_In_ CONST GUID* ClassGuid,
	_In_opt_ PCSTR DeviceDescription,
	_In_opt_ HWND hwndParent,
	_In_ DWORD CreationFlags,
	_Out_opt_ PSP_DEVINFO_DATA DeviceInfoData);
typedef BOOL(
	WINAPI* SetupDiSetDeviceRegistryPropertyA_t)(_In_ HDEVINFO DeviceInfoSet, _Inout_ PSP_DEVINFO_DATA DeviceInfoData, _In_ DWORD Property, _In_reads_bytes_opt_(PropertyBufferSize) CONST BYTE* PropertyBuffer, _In_ DWORD PropertyBufferSize);
typedef BOOL(WINAPI* SetupDiCallClassInstaller_t)(_In_ DI_FUNCTION InstallFunction, _In_ HDEVINFO DeviceInfoSet, _In_opt_ PSP_DEVINFO_DATA DeviceInfoData);
typedef BOOL(WINAPI* SetupDiDestroyDeviceInfoList_t)(_In_ HDEVINFO DeviceInfoSet);
typedef HDEVINFO(
	WINAPI* SetupDiGetClassDevsExA_t)(_In_opt_ CONST GUID* ClassGuid, _In_opt_ PCSTR Enumerator, _In_opt_ HWND hwndParent, _In_ DWORD Flags, _In_opt_ HDEVINFO DeviceInfoSet, _In_opt_ PCSTR MachineName, _Reserved_ PVOID Reserved);
typedef BOOL(WINAPI* SetupDiOpenDeviceInfoA_t)(_In_ HDEVINFO DeviceInfoSet, _In_ PCSTR DeviceInstanceId, _In_opt_ HWND hwndParent, _In_ DWORD OpenFlags, _Out_opt_ PSP_DEVINFO_DATA DeviceInfoData);
typedef BOOL(WINAPI* SetupDiEnumDeviceInfo_t)(_In_ HDEVINFO DeviceInfoSet, _In_ DWORD MemberIndex, _Out_ PSP_DEVINFO_DATA DeviceInfoData);
typedef BOOL(
	WINAPI* SetupDiSetClassInstallParamsA_t)(_In_ HDEVINFO DeviceInfoSet, _In_opt_ PSP_DEVINFO_DATA DeviceInfoData, _In_reads_bytes_opt_(ClassInstallParamsSize) PSP_CLASSINSTALL_HEADER ClassInstallParams, _In_ DWORD ClassInstallParamsSize);
typedef CONFIGRET(WINAPI* CM_Get_Device_ID_ExA_t)(_In_ DEVINST dnDevInst, _Out_writes_(BufferLen) PSTR Buffer, _In_ ULONG BufferLen, _In_ ULONG ulFlags, _In_opt_ HMACHINE hMachine);
typedef BOOL(
	WINAPI* SetupDiGetDeviceInstanceIdA_t)(_In_ HDEVINFO DeviceInfoSet, _In_ PSP_DEVINFO_DATA DeviceInfoData, _Out_writes_opt_(DeviceInstanceIdSize) PSTR DeviceInstanceId, _In_ DWORD DeviceInstanceIdSize, _Out_opt_ PDWORD RequiredSize);

namespace ZeroTier {

namespace {

// Static/singleton class that when initialized loads a bunch of environment information and a few dynamically loaded DLLs
class WindowsEthernetTapEnv {
  public:
	WindowsEthernetTapEnv()
	{
#ifdef _WIN64
		is64Bit = TRUE;
		// tapDriverPath = "\\tap-windows\\x64\\zttap300.inf";
#else
		is64Bit = FALSE;
		IsWow64Process(GetCurrentProcess(), &is64Bit);
		if (is64Bit) {
			fprintf(stderr, "FATAL: you must use the 64-bit ZeroTier One service on 64-bit Windows systems\r\n");
			_exit(1);
		}
		// tapDriverPath = "\\tap-windows\\x86\\zttap300.inf";
#endif
		tapDriverName = "zttap300";
		tapDriverPath = "\\zttap300.inf";

		setupApiMod = LoadLibraryA("setupapi.dll");
		if (! setupApiMod) {
			fprintf(stderr, "FATAL: unable to dynamically load setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiGetINFClassA = (SetupDiGetINFClassA_t)GetProcAddress(setupApiMod, "SetupDiGetINFClassA"))) {
			fprintf(stderr, "FATAL: SetupDiGetINFClassA not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiCreateDeviceInfoList = (SetupDiCreateDeviceInfoList_t)GetProcAddress(setupApiMod, "SetupDiCreateDeviceInfoList"))) {
			fprintf(stderr, "FATAL: SetupDiCreateDeviceInfoList not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiCreateDeviceInfoA = (SetupDiCreateDeviceInfoA_t)GetProcAddress(setupApiMod, "SetupDiCreateDeviceInfoA"))) {
			fprintf(stderr, "FATAL: SetupDiCreateDeviceInfoA not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiSetDeviceRegistryPropertyA = (SetupDiSetDeviceRegistryPropertyA_t)GetProcAddress(setupApiMod, "SetupDiSetDeviceRegistryPropertyA"))) {
			fprintf(stderr, "FATAL: SetupDiSetDeviceRegistryPropertyA not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiCallClassInstaller = (SetupDiCallClassInstaller_t)GetProcAddress(setupApiMod, "SetupDiCallClassInstaller"))) {
			fprintf(stderr, "FATAL: SetupDiCallClassInstaller not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiDestroyDeviceInfoList = (SetupDiDestroyDeviceInfoList_t)GetProcAddress(setupApiMod, "SetupDiDestroyDeviceInfoList"))) {
			fprintf(stderr, "FATAL: SetupDiDestroyDeviceInfoList not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiGetClassDevsExA = (SetupDiGetClassDevsExA_t)GetProcAddress(setupApiMod, "SetupDiGetClassDevsExA"))) {
			fprintf(stderr, "FATAL: SetupDiGetClassDevsExA not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiOpenDeviceInfoA = (SetupDiOpenDeviceInfoA_t)GetProcAddress(setupApiMod, "SetupDiOpenDeviceInfoA"))) {
			fprintf(stderr, "FATAL: SetupDiOpenDeviceInfoA not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiEnumDeviceInfo = (SetupDiEnumDeviceInfo_t)GetProcAddress(setupApiMod, "SetupDiEnumDeviceInfo"))) {
			fprintf(stderr, "FATAL: SetupDiEnumDeviceInfo not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiSetClassInstallParamsA = (SetupDiSetClassInstallParamsA_t)GetProcAddress(setupApiMod, "SetupDiSetClassInstallParamsA"))) {
			fprintf(stderr, "FATAL: SetupDiSetClassInstallParamsA not found in setupapi.dll\r\n");
			_exit(1);
		}
		if (! (this->SetupDiGetDeviceInstanceIdA = (SetupDiGetDeviceInstanceIdA_t)GetProcAddress(setupApiMod, "SetupDiGetDeviceInstanceIdA"))) {
			fprintf(stderr, "FATAL: SetupDiGetDeviceInstanceIdA not found in setupapi.dll\r\n");
			_exit(1);
		}

		newDevMod = LoadLibraryA("newdev.dll");
		if (! newDevMod) {
			fprintf(stderr, "FATAL: unable to dynamically load newdev.dll\r\n");
			_exit(1);
		}
		if (! (this->UpdateDriverForPlugAndPlayDevicesA = (UpdateDriverForPlugAndPlayDevicesA_t)GetProcAddress(newDevMod, "UpdateDriverForPlugAndPlayDevicesA"))) {
			fprintf(stderr, "FATAL: UpdateDriverForPlugAndPlayDevicesA not found in newdev.dll\r\n");
			_exit(1);
		}

		cfgMgrMod = LoadLibraryA("cfgmgr32.dll");
		if (! cfgMgrMod) {
			fprintf(stderr, "FATAL: unable to dynamically load cfgmgr32.dll\r\n");
			_exit(1);
		}
		if (! (this->CM_Get_Device_ID_ExA = (CM_Get_Device_ID_ExA_t)GetProcAddress(cfgMgrMod, "CM_Get_Device_ID_ExA"))) {
			fprintf(stderr, "FATAL: CM_Get_Device_ID_ExA not found in cfgmgr32.dll\r\n");
			_exit(1);
		}
	}

	BOOL is64Bit;	// is the system 64-bit, regardless of whether this binary is or not
	std::string tapDriverPath;
	std::string tapDriverName;

	UpdateDriverForPlugAndPlayDevicesA_t UpdateDriverForPlugAndPlayDevicesA;

	SetupDiGetINFClassA_t SetupDiGetINFClassA;
	SetupDiCreateDeviceInfoList_t SetupDiCreateDeviceInfoList;
	SetupDiCreateDeviceInfoA_t SetupDiCreateDeviceInfoA;
	SetupDiSetDeviceRegistryPropertyA_t SetupDiSetDeviceRegistryPropertyA;
	SetupDiCallClassInstaller_t SetupDiCallClassInstaller;
	SetupDiDestroyDeviceInfoList_t SetupDiDestroyDeviceInfoList;
	SetupDiGetClassDevsExA_t SetupDiGetClassDevsExA;
	SetupDiOpenDeviceInfoA_t SetupDiOpenDeviceInfoA;
	SetupDiEnumDeviceInfo_t SetupDiEnumDeviceInfo;
	SetupDiSetClassInstallParamsA_t SetupDiSetClassInstallParamsA;
	SetupDiGetDeviceInstanceIdA_t SetupDiGetDeviceInstanceIdA;

	CM_Get_Device_ID_ExA_t CM_Get_Device_ID_ExA;

  private:
	HMODULE setupApiMod;
	HMODULE newDevMod;
	HMODULE cfgMgrMod;
};
static const WindowsEthernetTapEnv WINENV;

// Only create or delete devices one at a time
static Mutex _systemTapInitLock;

// Only perform installation or uninstallation options one at a time
static Mutex _systemDeviceManagementLock;

}	// anonymous namespace

std::string WindowsEthernetTap::addNewPersistentTapDevice(const char* pathToInf, std::string& deviceInstanceId)
{
	Mutex::Lock _l(_systemDeviceManagementLock);

	GUID classGuid;
	char className[1024];
	if (! WINENV.SetupDiGetINFClassA(pathToInf, &classGuid, className, sizeof(className), (PDWORD)0)) {
		return std::string("SetupDiGetINFClassA() failed -- unable to read zttap driver INF file");
	}

	HDEVINFO deviceInfoSet = WINENV.SetupDiCreateDeviceInfoList(&classGuid, (HWND)0);
	if (deviceInfoSet == INVALID_HANDLE_VALUE) {
		return std::string("SetupDiCreateDeviceInfoList() failed");
	}

	SP_DEVINFO_DATA deviceInfoData;
	memset(&deviceInfoData, 0, sizeof(deviceInfoData));
	deviceInfoData.cbSize = sizeof(deviceInfoData);
	if (! WINENV.SetupDiCreateDeviceInfoA(deviceInfoSet, className, &classGuid, (PCSTR)0, (HWND)0, DICD_GENERATE_ID, &deviceInfoData)) {
		WINENV.SetupDiDestroyDeviceInfoList(deviceInfoSet);
		return std::string("SetupDiCreateDeviceInfoA() failed");
	}

	if (! WINENV.SetupDiSetDeviceRegistryPropertyA(deviceInfoSet, &deviceInfoData, SPDRP_HARDWAREID, (const BYTE*)WINENV.tapDriverName.c_str(), (DWORD)(WINENV.tapDriverName.length() + 1))) {
		WINENV.SetupDiDestroyDeviceInfoList(deviceInfoSet);
		return std::string("SetupDiSetDeviceRegistryPropertyA() failed");
	}

	if (! WINENV.SetupDiCallClassInstaller(DIF_REGISTERDEVICE, deviceInfoSet, &deviceInfoData)) {
		WINENV.SetupDiDestroyDeviceInfoList(deviceInfoSet);
		return std::string("SetupDiCallClassInstaller(DIF_REGISTERDEVICE) failed");
	}

	// HACK: During upgrades, this can fail while the installer is still running. So make 60 attempts
	// with a 1s delay between each attempt.
	bool driverInstalled = false;
	for (int retryCounter = 0; retryCounter < 60; ++retryCounter) {
		BOOL rebootRequired = FALSE;
		if (WINENV.UpdateDriverForPlugAndPlayDevicesA((HWND)0, WINENV.tapDriverName.c_str(), pathToInf, INSTALLFLAG_FORCE | INSTALLFLAG_NONINTERACTIVE, &rebootRequired)) {
			driverInstalled = true;
			break;
		}
		else
			Sleep(1000);
	}
	if (! driverInstalled) {
		WINENV.SetupDiDestroyDeviceInfoList(deviceInfoSet);
		return std::string("UpdateDriverForPlugAndPlayDevices() failed (made 60 attempts)");
	}

	char iidbuf[1024];
	DWORD iidReqSize = sizeof(iidbuf);
	if (WINENV.SetupDiGetDeviceInstanceIdA(deviceInfoSet, &deviceInfoData, iidbuf, sizeof(iidbuf), &iidReqSize)) {
		deviceInstanceId = iidbuf;
	}	// failure here is not fatal since we only need this on Vista and 2008 -- other versions fill it into the registry automatically

	WINENV.SetupDiDestroyDeviceInfoList(deviceInfoSet);

	return std::string();
}

std::string WindowsEthernetTap::destroyAllLegacyPersistentTapDevices()
{
	char subkeyName[1024];
	char subkeyClass[1024];
	char data[1024];

	std::set<std::string> instanceIdPathsToRemove;
	{
		HKEY nwAdapters;
		if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Control\\Class\\{4D36E972-E325-11CE-BFC1-08002BE10318}", 0, KEY_READ | KEY_WRITE, &nwAdapters) != ERROR_SUCCESS)
			return std::string("Could not open registry key");

		for (DWORD subkeyIndex = 0;; ++subkeyIndex) {
			DWORD type;
			DWORD dataLen;
			DWORD subkeyNameLen = sizeof(subkeyName);
			DWORD subkeyClassLen = sizeof(subkeyClass);
			FILETIME lastWriteTime;
			if (RegEnumKeyExA(nwAdapters, subkeyIndex, subkeyName, &subkeyNameLen, (DWORD*)0, subkeyClass, &subkeyClassLen, &lastWriteTime) == ERROR_SUCCESS) {
				type = 0;
				dataLen = sizeof(data);
				if (RegGetValueA(nwAdapters, subkeyName, "ComponentId", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS) {
					data[dataLen] = '\0';

					if ((! strnicmp(data, "zttap", 5)) && (WINENV.tapDriverName != data)) {
						std::string instanceIdPath;
						type = 0;
						dataLen = sizeof(data);
						if (RegGetValueA(nwAdapters, subkeyName, "DeviceInstanceID", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS)
							instanceIdPath.assign(data, dataLen);
						if (instanceIdPath.length() != 0)
							instanceIdPathsToRemove.insert(instanceIdPath);
					}
				}
			}
			else
				break;	 // end of list or failure
		}

		RegCloseKey(nwAdapters);
	}

	std::string errlist;
	for (std::set<std::string>::iterator iidp(instanceIdPathsToRemove.begin()); iidp != instanceIdPathsToRemove.end(); ++iidp) {
		std::string err = deletePersistentTapDevice(iidp->c_str());
		if (err.length() > 0) {
			if (errlist.length() > 0)
				errlist.push_back(',');
			errlist.append(err);
		}
	}
	return errlist;
}

std::string WindowsEthernetTap::destroyAllPersistentTapDevices()
{
	char subkeyName[1024];
	char subkeyClass[1024];
	char data[1024];

	std::set<std::string> instanceIdPathsToRemove;
	{
		HKEY nwAdapters;
		if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Control\\Class\\{4D36E972-E325-11CE-BFC1-08002BE10318}", 0, KEY_READ | KEY_WRITE, &nwAdapters) != ERROR_SUCCESS)
			return std::string("Could not open registry key");

		for (DWORD subkeyIndex = 0;; ++subkeyIndex) {
			DWORD type;
			DWORD dataLen;
			DWORD subkeyNameLen = sizeof(subkeyName);
			DWORD subkeyClassLen = sizeof(subkeyClass);
			FILETIME lastWriteTime;
			if (RegEnumKeyExA(nwAdapters, subkeyIndex, subkeyName, &subkeyNameLen, (DWORD*)0, subkeyClass, &subkeyClassLen, &lastWriteTime) == ERROR_SUCCESS) {
				type = 0;
				dataLen = sizeof(data);
				if (RegGetValueA(nwAdapters, subkeyName, "ComponentId", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS) {
					data[dataLen] = '\0';

					if (! strnicmp(data, "zttap", 5)) {
						std::string instanceIdPath;
						type = 0;
						dataLen = sizeof(data);
						if (RegGetValueA(nwAdapters, subkeyName, "DeviceInstanceID", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS)
							instanceIdPath.assign(data, dataLen);
						if (instanceIdPath.length() != 0)
							instanceIdPathsToRemove.insert(instanceIdPath);
					}
				}
			}
			else
				break;	 // end of list or failure
		}

		RegCloseKey(nwAdapters);
	}

	std::string errlist;
	for (std::set<std::string>::iterator iidp(instanceIdPathsToRemove.begin()); iidp != instanceIdPathsToRemove.end(); ++iidp) {
		std::string err = deletePersistentTapDevice(iidp->c_str());
		if (err.length() > 0) {
			if (errlist.length() > 0)
				errlist.push_back(',');
			errlist.append(err);
		}
	}
	return errlist;
}

std::string WindowsEthernetTap::deletePersistentTapDevice(const char* instanceId)
{
	char iid[256];
	SP_REMOVEDEVICE_PARAMS rmdParams;

	memset(&rmdParams, 0, sizeof(rmdParams));
	rmdParams.ClassInstallHeader.cbSize = sizeof(SP_CLASSINSTALL_HEADER);
	rmdParams.ClassInstallHeader.InstallFunction = DIF_REMOVE;
	rmdParams.Scope = DI_REMOVEDEVICE_GLOBAL;
	rmdParams.HwProfile = 0;

	Mutex::Lock _l(_systemDeviceManagementLock);

	HDEVINFO devInfo = WINENV.SetupDiGetClassDevsExA((const GUID*)0, (PCSTR)0, (HWND)0, DIGCF_ALLCLASSES, (HDEVINFO)0, (PCSTR)0, (PVOID)0);
	if (devInfo == INVALID_HANDLE_VALUE)
		return std::string("SetupDiGetClassDevsExA() failed");
	WINENV.SetupDiOpenDeviceInfoA(devInfo, instanceId, (HWND)0, 0, (PSP_DEVINFO_DATA)0);

	SP_DEVINFO_DATA devInfoData;
	memset(&devInfoData, 0, sizeof(devInfoData));
	devInfoData.cbSize = sizeof(devInfoData);
	for (DWORD devIndex = 0; WINENV.SetupDiEnumDeviceInfo(devInfo, devIndex, &devInfoData); devIndex++) {
		if ((WINENV.CM_Get_Device_ID_ExA(devInfoData.DevInst, iid, sizeof(iid), 0, (HMACHINE)0) == CR_SUCCESS) && (! strcmp(iid, instanceId))) {
			if (! WINENV.SetupDiSetClassInstallParamsA(devInfo, &devInfoData, &rmdParams.ClassInstallHeader, sizeof(rmdParams))) {
				WINENV.SetupDiDestroyDeviceInfoList(devInfo);
				return std::string("SetupDiSetClassInstallParams() failed");
			}

			if (! WINENV.SetupDiCallClassInstaller(DIF_REMOVE, devInfo, &devInfoData)) {
				WINENV.SetupDiDestroyDeviceInfoList(devInfo);
				return std::string("SetupDiCallClassInstaller(DIF_REMOVE) failed");
			}

			WINENV.SetupDiDestroyDeviceInfoList(devInfo);
			return std::string();
		}
	}

	WINENV.SetupDiDestroyDeviceInfoList(devInfo);
	return std::string("instance ID not found");
}

bool WindowsEthernetTap::setPersistentTapDeviceState(const char* instanceId, bool enabled)
{
	char iid[256];
	SP_PROPCHANGE_PARAMS params;

	Mutex::Lock _l(_systemDeviceManagementLock);

	HDEVINFO devInfo = WINENV.SetupDiGetClassDevsExA((const GUID*)0, (PCSTR)0, (HWND)0, DIGCF_ALLCLASSES, (HDEVINFO)0, (PCSTR)0, (PVOID)0);
	if (devInfo == INVALID_HANDLE_VALUE)
		return false;
	WINENV.SetupDiOpenDeviceInfoA(devInfo, instanceId, (HWND)0, 0, (PSP_DEVINFO_DATA)0);

	SP_DEVINFO_DATA devInfoData;
	memset(&devInfoData, 0, sizeof(devInfoData));
	devInfoData.cbSize = sizeof(devInfoData);
	for (DWORD devIndex = 0; WINENV.SetupDiEnumDeviceInfo(devInfo, devIndex, &devInfoData); devIndex++) {
		if ((WINENV.CM_Get_Device_ID_ExA(devInfoData.DevInst, iid, sizeof(iid), 0, (HMACHINE)0) == CR_SUCCESS) && (! strcmp(iid, instanceId))) {
			memset(&params, 0, sizeof(params));
			params.ClassInstallHeader.cbSize = sizeof(SP_CLASSINSTALL_HEADER);
			params.ClassInstallHeader.InstallFunction = DIF_PROPERTYCHANGE;
			params.StateChange = enabled ? DICS_ENABLE : DICS_DISABLE;
			params.Scope = DICS_FLAG_GLOBAL;
			params.HwProfile = 0;

			WINENV.SetupDiSetClassInstallParamsA(devInfo, &devInfoData, &params.ClassInstallHeader, sizeof(params));
			WINENV.SetupDiCallClassInstaller(DIF_PROPERTYCHANGE, devInfo, &devInfoData);

			memset(&params, 0, sizeof(params));
			params.ClassInstallHeader.cbSize = sizeof(SP_CLASSINSTALL_HEADER);
			params.ClassInstallHeader.InstallFunction = DIF_PROPERTYCHANGE;
			params.StateChange = enabled ? DICS_ENABLE : DICS_DISABLE;
			params.Scope = DICS_FLAG_CONFIGSPECIFIC;
			params.HwProfile = 0;

			WINENV.SetupDiSetClassInstallParamsA(devInfo, &devInfoData, &params.ClassInstallHeader, sizeof(params));
			WINENV.SetupDiCallClassInstaller(DIF_PROPERTYCHANGE, devInfo, &devInfoData);

			WINENV.SetupDiDestroyDeviceInfoList(devInfo);
			return true;
		}
	}

	WINENV.SetupDiDestroyDeviceInfoList(devInfo);
	return false;
}

WindowsEthernetTap::WindowsEthernetTap(
	const char* hp,
	const MAC& mac,
	unsigned int mtu,
	unsigned int metric,
	uint64_t nwid,
	const char* friendlyName,
	void (*handler)(void*, void*, uint64_t, const MAC&, const MAC&, unsigned int, unsigned int, const void*, unsigned int),
	void* arg)
	: _handler(handler)
	, _arg(arg)
	, _mac(mac)
	, _nwid(nwid)
	, _mtu(mtu)
	, _tap(INVALID_HANDLE_VALUE)
	, _friendlyName(friendlyName)
	, _injectSemaphore(INVALID_HANDLE_VALUE)
	, _pathToHelpers(hp)
	, _run(true)
	, _initialized(false)
	, _enabled(true)
	, _lastIfAddrsUpdate(0)
{
	char subkeyName[1024];
	char subkeyClass[1024];
	char data[1024];
	char tag[24];

	// We "tag" registry entries with the network ID to identify persistent devices
	OSUtils::ztsnprintf(tag, sizeof(tag), "%.16llx", (unsigned long long)nwid);

	Mutex::Lock _l(_systemTapInitLock);

	HKEY nwAdapters;
	if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Control\\Class\\{4D36E972-E325-11CE-BFC1-08002BE10318}", 0, KEY_READ | KEY_WRITE, &nwAdapters) != ERROR_SUCCESS)
		throw std::runtime_error("unable to open registry key for network adapter enumeration");

	// Look for the tap instance that corresponds with this network
	for (DWORD subkeyIndex = 0;; ++subkeyIndex) {
		DWORD type;
		DWORD dataLen;
		DWORD subkeyNameLen = sizeof(subkeyName);
		DWORD subkeyClassLen = sizeof(subkeyClass);
		FILETIME lastWriteTime;
		if (RegEnumKeyExA(nwAdapters, subkeyIndex, subkeyName, &subkeyNameLen, (DWORD*)0, subkeyClass, &subkeyClassLen, &lastWriteTime) == ERROR_SUCCESS) {
			type = 0;
			dataLen = sizeof(data);
			if (RegGetValueA(nwAdapters, subkeyName, "ComponentId", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS) {
				data[dataLen] = (char)0;

				if (WINENV.tapDriverName == data) {
					std::string instanceId;
					type = 0;
					dataLen = sizeof(data);
					if (RegGetValueA(nwAdapters, subkeyName, "NetCfgInstanceId", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS)
						instanceId.assign(data, dataLen);

					std::string instanceIdPath;
					type = 0;
					dataLen = sizeof(data);
					if (RegGetValueA(nwAdapters, subkeyName, "DeviceInstanceID", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS)
						instanceIdPath.assign(data, dataLen);

					if ((_netCfgInstanceId.length() == 0) && (instanceId.length() != 0) && (instanceIdPath.length() != 0)) {
						type = 0;
						dataLen = sizeof(data);
						if (RegGetValueA(nwAdapters, subkeyName, "_ZeroTierTapIdentifier", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS) {
							data[dataLen] = '\0';
							if (! strcmp(data, tag)) {
								_netCfgInstanceId = instanceId;
								_deviceInstanceId = instanceIdPath;

								_mySubkeyName = subkeyName;
								break;	 // found it!
							}
						}
					}
				}
			}
		}
		else
			break;	 // no more subkeys or error occurred enumerating them
	}

	// If there is no device, try to create one
	bool creatingNewDevice = (_netCfgInstanceId.length() == 0);
	std::string newDeviceInstanceId;
	if (creatingNewDevice) {
		for (int getNewAttemptCounter = 0; getNewAttemptCounter < 2; ++getNewAttemptCounter) {
			for (DWORD subkeyIndex = 0;; ++subkeyIndex) {
				DWORD type;
				DWORD dataLen;
				DWORD subkeyNameLen = sizeof(subkeyName);
				DWORD subkeyClassLen = sizeof(subkeyClass);
				FILETIME lastWriteTime;
				if (RegEnumKeyExA(nwAdapters, subkeyIndex, subkeyName, &subkeyNameLen, (DWORD*)0, subkeyClass, &subkeyClassLen, &lastWriteTime) == ERROR_SUCCESS) {
					type = 0;
					dataLen = sizeof(data);
					if (RegGetValueA(nwAdapters, subkeyName, "ComponentId", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS) {
						data[dataLen] = '\0';

						if (WINENV.tapDriverName == data) {
							type = 0;
							dataLen = sizeof(data);
							if ((RegGetValueA(nwAdapters, subkeyName, "_ZeroTierTapIdentifier", RRF_RT_ANY, &type, (PVOID)data, &dataLen) != ERROR_SUCCESS) || (dataLen <= 0)) {
								type = 0;
								dataLen = sizeof(data);
								if (RegGetValueA(nwAdapters, subkeyName, "NetCfgInstanceId", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS) {
									RegSetKeyValueA(nwAdapters, subkeyName, "_ZeroTierTapIdentifier", REG_SZ, tag, (DWORD)(strlen(tag) + 1));

									_netCfgInstanceId.assign(data, dataLen);

									type = 0;
									dataLen = sizeof(data);
									if (RegGetValueA(nwAdapters, subkeyName, "DeviceInstanceID", RRF_RT_ANY, &type, (PVOID)data, &dataLen) == ERROR_SUCCESS)
										_deviceInstanceId.assign(data, dataLen);

									_mySubkeyName = subkeyName;

									// Disable DHCP by default on new devices
									HKEY tcpIpInterfaces;
									if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\services\\Tcpip\\Parameters\\Interfaces", 0, KEY_READ | KEY_WRITE, &tcpIpInterfaces) == ERROR_SUCCESS) {
										DWORD enable = 0;
										RegSetKeyValueA(tcpIpInterfaces, _netCfgInstanceId.c_str(), "EnableDHCP", REG_DWORD, &enable, sizeof(enable));
										RegCloseKey(tcpIpInterfaces);
									}

									break;	 // found an unused zttap device
								}
							}
						}
					}
				}
				else
					break;	 // no more keys or error occurred
			}

			if (_netCfgInstanceId.length() > 0) {
				break;	 // found an unused zttap device
			}
			else {
				// no unused zttap devices, so create one
				std::string errm = addNewPersistentTapDevice((std::string(_pathToHelpers) + WINENV.tapDriverPath).c_str(), newDeviceInstanceId);
				if (errm.length() > 0)
					throw std::runtime_error(std::string("unable to create new device instance: ") + errm);
			}
		}
	}

	if (_netCfgInstanceId.length() > 0) {
		char tmps[64];
		unsigned int tmpsl = OSUtils::ztsnprintf(tmps, sizeof(tmps), "%.2X-%.2X-%.2X-%.2X-%.2X-%.2X", (unsigned int)mac[0], (unsigned int)mac[1], (unsigned int)mac[2], (unsigned int)mac[3], (unsigned int)mac[4], (unsigned int)mac[5]) + 1;
		RegSetKeyValueA(nwAdapters, _mySubkeyName.c_str(), "NetworkAddress", REG_SZ, tmps, tmpsl);
		RegSetKeyValueA(nwAdapters, _mySubkeyName.c_str(), "MAC", REG_SZ, tmps, tmpsl);
		tmpsl = OSUtils::ztsnprintf(tmps, sizeof(tmps), "%d", mtu);
		RegSetKeyValueA(nwAdapters, _mySubkeyName.c_str(), "MTU", REG_SZ, tmps, tmpsl);

		DWORD tmp = 0;
		RegSetKeyValueA(nwAdapters, _mySubkeyName.c_str(), "*NdisDeviceType", REG_DWORD, (LPCVOID)&tmp, sizeof(tmp));
		tmp = IF_TYPE_ETHERNET_CSMACD;
		RegSetKeyValueA(nwAdapters, _mySubkeyName.c_str(), "*IfType", REG_DWORD, (LPCVOID)&tmp, sizeof(tmp));

		if (creatingNewDevice) {
			// Vista/2008 does not set this
			if (newDeviceInstanceId.length() > 0)
				RegSetKeyValueA(nwAdapters, _mySubkeyName.c_str(), "DeviceInstanceID", REG_SZ, newDeviceInstanceId.c_str(), (DWORD)newDeviceInstanceId.length());

			// Set EnableDHCP to 0 by default on new devices
			tmp = 0;
			RegSetKeyValueA(nwAdapters, _mySubkeyName.c_str(), "EnableDHCP", REG_DWORD, (LPCVOID)&tmp, sizeof(tmp));
		}
		RegCloseKey(nwAdapters);
	}
	else {
		RegCloseKey(nwAdapters);
		throw std::runtime_error("unable to find or create tap adapter");
	}

	{
		char nobraces[128];	  // strip braces from GUID before converting it, because Windows
		const char* nbtmp1 = _netCfgInstanceId.c_str();
		char* nbtmp2 = nobraces;
		while (*nbtmp1) {
			if ((*nbtmp1 != '{') && (*nbtmp1 != '}'))
				*nbtmp2++ = *nbtmp1;
			++nbtmp1;
		}
		*nbtmp2 = (char)0;
		if (UuidFromStringA((RPC_CSTR)nobraces, &_deviceGuid) != RPC_S_OK)
			throw std::runtime_error("unable to convert instance ID GUID to native GUID (invalid NetCfgInstanceId in registry?)");
	}

	// Get the LUID, which is one of like four fucking ways to refer to a network device in Windows
	if (ConvertInterfaceGuidToLuid(&_deviceGuid, &_deviceLuid) != NO_ERROR)
		throw std::runtime_error("unable to convert device interface GUID to LUID");

	//_initialized = true;

	if (friendlyName)
		setFriendlyName(friendlyName);

	_injectSemaphore = CreateSemaphore(NULL, 0, 1, NULL);
	_thread = Thread::start(this);
}

WindowsEthernetTap::~WindowsEthernetTap()
{
	WinDNSHelper::removeDNS(_nwid);
	_run = false;
	ReleaseSemaphore(_injectSemaphore, 1, NULL);
	Thread::join(_thread);
	CloseHandle(_injectSemaphore);
	setPersistentTapDeviceState(_deviceInstanceId.c_str(), false);
}

void WindowsEthernetTap::setEnabled(bool en)
{
	_enabled = en;
}

bool WindowsEthernetTap::enabled() const
{
	return _enabled;
}

bool WindowsEthernetTap::addIp(const InetAddress& ip)
{
	if (! ip.netmaskBits())	  // sanity check... netmask of 0.0.0.0 is WUT?
		return false;

	Mutex::Lock _l(_assignedIps_m);
	if (std::find(_assignedIps.begin(), _assignedIps.end(), ip) != _assignedIps.end())
		return true;
	_assignedIps.push_back(ip);
	_syncIps();
	return true;
}

bool WindowsEthernetTap::removeIp(const InetAddress& ip)
{
	if (ip.isV6())
		return true;

	{
		Mutex::Lock _l(_assignedIps_m);
		std::vector<InetAddress>::iterator aip(std::find(_assignedIps.begin(), _assignedIps.end(), ip));
		if (aip != _assignedIps.end())
			_assignedIps.erase(aip);
	}

	if (! _initialized)
		return false;

	try {
		MIB_UNICASTIPADDRESS_TABLE* ipt = (MIB_UNICASTIPADDRESS_TABLE*)0;
		if (GetUnicastIpAddressTable(AF_UNSPEC, &ipt) == NO_ERROR) {
			if ((ipt) && (ipt->NumEntries > 0)) {
				for (DWORD i = 0; i < (DWORD)ipt->NumEntries; ++i) {
					if (ipt->Table[i].InterfaceLuid.Value == _deviceLuid.Value) {
						InetAddress addr;
						switch (ipt->Table[i].Address.si_family) {
							case AF_INET:
								addr.set(&(ipt->Table[i].Address.Ipv4.sin_addr.S_un.S_addr), 4, ipt->Table[i].OnLinkPrefixLength);
								break;
							case AF_INET6:
								addr.set(ipt->Table[i].Address.Ipv6.sin6_addr.u.Byte, 16, ipt->Table[i].OnLinkPrefixLength);
								if (addr.ipScope() == InetAddress::IP_SCOPE_LINK_LOCAL)
									continue;	// can't remove link-local IPv6 addresses
								break;
						}
						if (addr == ip) {
							DeleteUnicastIpAddressEntry(&(ipt->Table[i]));
							FreeMibTable(ipt);

							if (ip.isV4()) {
								std::vector<std::string> regIps(_getRegistryIPv4Value("IPAddress"));
								std::vector<std::string> regSubnetMasks(_getRegistryIPv4Value("SubnetMask"));
								char ipbuf[64];
								std::string ipstr(ip.toIpString(ipbuf));
								for (std::vector<std::string>::iterator rip(regIps.begin()), rm(regSubnetMasks.begin()); ((rip != regIps.end()) && (rm != regSubnetMasks.end())); ++rip, ++rm) {
									if (*rip == ipstr) {
										regIps.erase(rip);
										regSubnetMasks.erase(rm);
										_setRegistryIPv4Value("IPAddress", regIps);
										_setRegistryIPv4Value("SubnetMask", regSubnetMasks);
										break;
									}
								}
							}

							return true;
						}
					}
				}
			}
			FreeMibTable((PVOID)ipt);
		}
	}
	catch (...) {
	}
	return false;
}

std::vector<InetAddress> WindowsEthernetTap::ips() const
{
	static const InetAddress linkLocalLoopback("fe80::1/64");	// what is this and why does Windows assign it?
	std::vector<InetAddress> addrs;

	if (! _initialized)
		return addrs;

	uint64_t now = OSUtils::now();

	if ((now - _lastIfAddrsUpdate) <= GETIFADDRS_CACHE_TIME) {
		return _ifaddrs;
	}

	_lastIfAddrsUpdate = now;

	try {
		MIB_UNICASTIPADDRESS_TABLE* ipt = (MIB_UNICASTIPADDRESS_TABLE*)0;
		if (GetUnicastIpAddressTable(AF_UNSPEC, &ipt) == NO_ERROR) {
			if ((ipt) && (ipt->NumEntries > 0)) {
				for (DWORD i = 0; i < (DWORD)ipt->NumEntries; ++i) {
					if (ipt->Table[i].InterfaceLuid.Value == _deviceLuid.Value) {
						switch (ipt->Table[i].Address.si_family) {
							case AF_INET: {
								InetAddress ip(&(ipt->Table[i].Address.Ipv4.sin_addr.S_un.S_addr), 4, ipt->Table[i].OnLinkPrefixLength);
								if (ip != InetAddress::LO4)
									addrs.push_back(ip);
							} break;
							case AF_INET6: {
								InetAddress ip(ipt->Table[i].Address.Ipv6.sin6_addr.u.Byte, 16, ipt->Table[i].OnLinkPrefixLength);
								if ((ip != linkLocalLoopback) && (ip != InetAddress::LO6))
									addrs.push_back(ip);
							} break;
						}
					}
				}
			}
			FreeMibTable(ipt);
		}
	}
	catch (...) {
	}	// sanity check, shouldn't happen unless out of memory

	std::sort(addrs.begin(), addrs.end());
	addrs.erase(std::unique(addrs.begin(), addrs.end()), addrs.end());

	_ifaddrs = addrs;

	return addrs;
}

void WindowsEthernetTap::put(const MAC& from, const MAC& to, unsigned int etherType, const void* data, unsigned int len)
{
	if ((! _initialized) || (! _enabled) || (_tap == INVALID_HANDLE_VALUE) || (len > _mtu))
		return;

	Mutex::Lock _l(_injectPending_m);
	_injectPending.emplace();
	_injectPending.back().len = len + 14;
	char* const d = _injectPending.back().data;
	to.copyTo(d, 6);
	from.copyTo(d + 6, 6);
	d[12] = (char)((etherType >> 8) & 0xff);
	d[13] = (char)(etherType & 0xff);
	memcpy(d + 14, data, len);

	ReleaseSemaphore(_injectSemaphore, 1, NULL);
}

std::string WindowsEthernetTap::deviceName() const
{
	char tmp[1024];
	if (ConvertInterfaceLuidToNameA(&_deviceLuid, tmp, sizeof(tmp)) != NO_ERROR)
		return std::string("[ConvertInterfaceLuidToName() failed]");
	return std::string(tmp);
}

void WindowsEthernetTap::setFriendlyName(const char* dn)
{
	if (! _initialized)
		return;

	HKEY ifp;
	if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, (std::string("SYSTEM\\CurrentControlSet\\Control\\Network\\{4D36E972-E325-11CE-BFC1-08002BE10318}\\") + _netCfgInstanceId).c_str(), 0, KEY_READ | KEY_WRITE, &ifp) == ERROR_SUCCESS) {
		RegSetKeyValueA(ifp, "Connection", "Name", REG_SZ, (LPCVOID)dn, (DWORD)(strlen(dn) + 1));
		RegCloseKey(ifp);
	}

	HRESULT hr = S_OK;

	INetSharingManager* nsm;
	hr = CoCreateInstance(__uuidof(NetSharingManager), NULL, CLSCTX_ALL, __uuidof(INetSharingManager), (void**)&nsm);
	if (hr != S_OK)
		return;

	bool found = false;
	INetSharingEveryConnectionCollection* nsecc = nullptr;
	hr = nsm->get_EnumEveryConnection(&nsecc);
	if (! nsecc) {
		fprintf(stderr, "Failed to get NSM connections");
		return;
	}

	IEnumVARIANT* ev = nullptr;
	IUnknown* unk = nullptr;
	hr = nsecc->get__NewEnum(&unk);
	if (unk) {
		hr = unk->QueryInterface(__uuidof(IEnumVARIANT), (void**)&ev);
		unk->Release();
	}
	if (ev) {
		VARIANT v;
		VariantInit(&v);

		while ((S_OK == ev->Next(1, &v, NULL)) && found == FALSE) {
			if (V_VT(&v) == VT_UNKNOWN) {
				INetConnection* nc = nullptr;
				V_UNKNOWN(&v)->QueryInterface(__uuidof(INetConnection), (void**)&nc);
				if (nc) {
					NETCON_PROPERTIES* ncp = nullptr;
					nc->GetProperties(&ncp);

					if (ncp != nullptr) {
						GUID curId = ncp->guidId;
						if (curId == _deviceGuid) {
							wchar_t wtext[255];
							mbstowcs(wtext, dn, strlen(dn) + 1);
							nc->Rename(wtext);
							found = true;
						}
					}
					nc->Release();
				}
			}
			VariantClear(&v);
		}
		ev->Release();
	}
	nsecc->Release();

	_friendlyName_m.lock();
	_friendlyName = dn;
	_friendlyName_m.unlock();
}

std::string WindowsEthernetTap::friendlyName() const
{
	Mutex::Lock l(_friendlyName_m);
	return _friendlyName;
}

void WindowsEthernetTap::scanMulticastGroups(std::vector<MulticastGroup>& added, std::vector<MulticastGroup>& removed)
{
	if (! _initialized)
		return;
	HANDLE t = _tap;
	if (t == INVALID_HANDLE_VALUE)
		return;

	std::vector<MulticastGroup> newGroups;

	// The ZT1 tap driver supports an IOCTL to get multicast memberships at the L2
	// level... something Windows does not seem to expose ordinarily. This lets
	// pretty much anything work... IPv4, IPv6, IPX, oldskool Netbios, who knows...
	unsigned char mcastbuf[TAP_WIN_IOCTL_GET_MULTICAST_MEMBERSHIPS_OUTPUT_BUF_SIZE];
	DWORD bytesReturned = 0;
	if (DeviceIoControl(t, TAP_WIN_IOCTL_GET_MULTICAST_MEMBERSHIPS, (LPVOID)mcastbuf, sizeof(mcastbuf), (LPVOID)mcastbuf, sizeof(mcastbuf), &bytesReturned, NULL)) {
		if ((bytesReturned > 0) && (bytesReturned <= TAP_WIN_IOCTL_GET_MULTICAST_MEMBERSHIPS_OUTPUT_BUF_SIZE)) {   // sanity check
			MAC mac;
			DWORD i = 0;
			while ((i + 6) <= bytesReturned) {
				mac.setTo(mcastbuf + i, 6);
				i += 6;
				if ((mac.isMulticast()) && (! mac.isBroadcast())) {
					// exclude the nulls that may be returned or any other junk Windows puts in there
					newGroups.push_back(MulticastGroup(mac, 0));
				}
			}
		}
	}

	std::vector<InetAddress> allIps(ips());
	for (std::vector<InetAddress>::iterator ip(allIps.begin()); ip != allIps.end(); ++ip)
		newGroups.push_back(MulticastGroup::deriveMulticastGroupForAddressResolution(*ip));

	std::sort(newGroups.begin(), newGroups.end());
	newGroups.erase(std::unique(newGroups.begin(), newGroups.end()), newGroups.end());

	for (std::vector<MulticastGroup>::iterator m(newGroups.begin()); m != newGroups.end(); ++m) {
		if (! std::binary_search(_multicastGroups.begin(), _multicastGroups.end(), *m))
			added.push_back(*m);
	}
	for (std::vector<MulticastGroup>::iterator m(_multicastGroups.begin()); m != _multicastGroups.end(); ++m) {
		if (! std::binary_search(newGroups.begin(), newGroups.end(), *m))
			removed.push_back(*m);
	}

	_multicastGroups.swap(newGroups);
}

void WindowsEthernetTap::setMtu(unsigned int mtu)
{
	if (mtu != _mtu) {
		_mtu = mtu;
		HKEY nwAdapters;
		if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Control\\Class\\{4D36E972-E325-11CE-BFC1-08002BE10318}", 0, KEY_READ | KEY_WRITE, &nwAdapters) == ERROR_SUCCESS) {
			char tmps[64];
			unsigned int tmpsl = OSUtils::ztsnprintf(tmps, sizeof(tmps), "%d", mtu);
			RegSetKeyValueA(nwAdapters, _mySubkeyName.c_str(), "MTU", REG_SZ, tmps, tmpsl);
			RegCloseKey(nwAdapters);
		}
	}
}

NET_IFINDEX WindowsEthernetTap::interfaceIndex() const
{
	NET_IFINDEX idx = -1;
	if (ConvertInterfaceLuidToIndex(&_deviceLuid, &idx) == NO_ERROR)
		return idx;
	return -1;
}

void WindowsEthernetTap::threadMain() throw()
{
	HRESULT hres = CoInitializeEx(0, COINIT_MULTITHREADED);
	if (FAILED(hres)) {
		fprintf(stderr, "WinEthernetTap: COM initialization failed");
		return;
	}

	char tapReadBuf[ZT_MAX_MTU + 32];
	char tapPath[128];
	HANDLE wait4[3];
	OVERLAPPED tapOvlRead, tapOvlWrite;

	OSUtils::ztsnprintf(tapPath, sizeof(tapPath), "\\\\.\\Global\\%s.tap", _netCfgInstanceId.c_str());

	try {
		while (_run) {
			// Because Windows
			Sleep(250);
			setPersistentTapDeviceState(_deviceInstanceId.c_str(), false);
			Sleep(250);
			setPersistentTapDeviceState(_deviceInstanceId.c_str(), true);
			Sleep(250);
			setPersistentTapDeviceState(_deviceInstanceId.c_str(), false);
			Sleep(250);
			setPersistentTapDeviceState(_deviceInstanceId.c_str(), true);
			Sleep(250);

			_tap = CreateFileA(tapPath, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_OVERLAPPED, NULL);
			if (_tap == INVALID_HANDLE_VALUE) {
				Sleep(250);
				continue;
			}

			{
				uint32_t tmpi = 1;
				DWORD bytesReturned = 0;
				DeviceIoControl(_tap, TAP_WIN_IOCTL_SET_MEDIA_STATUS, &tmpi, sizeof(tmpi), &tmpi, sizeof(tmpi), &bytesReturned, NULL);
			}

#ifdef ZT_WINDOWS_CREATE_FAKE_DEFAULT_ROUTE
			{
				/* This inserts a fake default route and a fake ARP entry, forcing
				 * Windows to detect this as a "real" network and apply proper
				 * firewall rules.
				 *
				 * This hack is completely stupid, but Windows made me do it
				 * by being broken and insane.
				 *
				 * Background: Windows tries to detect its network location by
				 * matching it to the ARP address of the default route. Networks
				 * without default routes are "unidentified networks" and cannot
				 * have their firewall classification changed by the user (easily).
				 *
				 * Yes, you read that right.
				 *
				 * The common workaround is to set *NdisDeviceType to 1, which
				 * totally disables all Windows firewall functionality. This is
				 * the answer you'll find on most forums for things like OpenVPN.
				 *
				 * Yes, you read that right.
				 *
				 * The default route workaround is also known, but for this to
				 * work there must be a known default IP that resolves to a known
				 * ARP address. This works for an OpenVPN tunnel, but not here
				 * because this isn't a tunnel. It's a mesh. There is no "other
				 * end," or any other known always on IP.
				 *
				 * So let's make a fake one and shove it in there along with its
				 * fake static ARP entry. Also makes it instant-on and static.
				 *
				 * We'll have to see what DHCP does with this. In the future we
				 * probably will not want to do this on DHCP-enabled networks, so
				 * when we enable DHCP we will go in and yank this wacko hacko from
				 * the routing table before doing so.
				 *
				 * Like Jesse Pinkman would say: "YEEEEAAH BITCH!" */
				const uint32_t fakeIp = htonl(0x19fffffe);	 // 25.255.255.254 -- unrouted IPv4 block
				for (int i = 0; i < 8; ++i) {
					MIB_IPNET_ROW2 ipnr;
					memset(&ipnr, 0, sizeof(ipnr));
					ipnr.Address.si_family = AF_INET;
					ipnr.Address.Ipv4.sin_addr.s_addr = fakeIp;
					ipnr.InterfaceLuid.Value = _deviceLuid.Value;
					ipnr.PhysicalAddress[0] = _mac[0] ^ 0x10;	// just make something up that's consistent and not part of this net
					ipnr.PhysicalAddress[1] = 0x00;
					ipnr.PhysicalAddress[2] = (UCHAR)((_deviceGuid.Data1 >> 24) & 0xff);
					ipnr.PhysicalAddress[3] = (UCHAR)((_deviceGuid.Data1 >> 16) & 0xff);
					ipnr.PhysicalAddress[4] = (UCHAR)((_deviceGuid.Data1 >> 8) & 0xff);
					ipnr.PhysicalAddress[5] = (UCHAR)(_deviceGuid.Data1 & 0xff);
					ipnr.PhysicalAddressLength = 6;
					ipnr.State = NlnsPermanent;
					ipnr.IsRouter = 1;
					ipnr.IsUnreachable = 0;
					ipnr.ReachabilityTime.LastReachable = 0x0fffffff;
					ipnr.ReachabilityTime.LastUnreachable = 1;
					DWORD result = CreateIpNetEntry2(&ipnr);
					if (result != NO_ERROR)
						Sleep(250);
					else
						break;
				}
				for (int i = 0; i < 8; ++i) {
					MIB_IPFORWARD_ROW2 nr;
					memset(&nr, 0, sizeof(nr));
					InitializeIpForwardEntry(&nr);
					nr.InterfaceLuid.Value = _deviceLuid.Value;
					nr.DestinationPrefix.Prefix.si_family = AF_INET;   // rest is left as 0.0.0.0/0
					nr.NextHop.si_family = AF_INET;
					nr.NextHop.Ipv4.sin_addr.s_addr = fakeIp;
					nr.Metric = 9999;	// do not use as real default route
					nr.Protocol = MIB_IPPROTO_NETMGMT;
					DWORD result = CreateIpForwardEntry2(&nr);
					if (result != NO_ERROR)
						Sleep(250);
					else
						break;
				}
			}
#endif

			// Assign or re-assign any should-be-assigned IPs in case we have restarted
			{
				Mutex::Lock _l(_assignedIps_m);
				_syncIps();
			}

			memset(&tapOvlRead, 0, sizeof(tapOvlRead));
			tapOvlRead.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
			memset(&tapOvlWrite, 0, sizeof(tapOvlWrite));
			tapOvlWrite.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

			wait4[0] = _injectSemaphore;
			wait4[1] = tapOvlRead.hEvent;
			wait4[2] = tapOvlWrite.hEvent;	 // only included if writeInProgress is true

			ReadFile(_tap, tapReadBuf, sizeof(tapReadBuf), NULL, &tapOvlRead);
			bool writeInProgress = false;
			ULONGLONG timeOfLastBorkCheck = GetTickCount64();
			_initialized = true;
			unsigned int oldmtu = _mtu;

			setFriendlyName(_friendlyName.c_str());

			while (_run) {
				DWORD waitResult = WaitForMultipleObjectsEx(writeInProgress ? 3 : 2, wait4, FALSE, 2500, TRUE);
				if (! _run)
					break;	 // will also break outer while(_run) since _run is false

				// Check for changes in MTU and break to restart tap device to reconfigure in this case
				if (_mtu != oldmtu)
					break;

				// Check for issues with adapter and close/reopen if any are detected. This
				// check fixes a while boatload of Windows adapter 'coma' issues after
				// sleep/wake and when adapters are added/removed. Basically if the tap
				// device is borked, whack it.
				{
					ULONGLONG tc = GetTickCount64();
					if ((tc - timeOfLastBorkCheck) >= 2500) {
						timeOfLastBorkCheck = tc;
						char aabuf[16384];
						ULONG aalen = sizeof(aabuf);
						if (GetAdaptersAddresses(
								AF_UNSPEC,
								GAA_FLAG_SKIP_UNICAST | GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_DNS_SERVER | GAA_FLAG_SKIP_FRIENDLY_NAME,
								(void*)0,
								reinterpret_cast<PIP_ADAPTER_ADDRESSES>(aabuf),
								&aalen)
							== NO_ERROR) {
							bool isBorked = false;

							PIP_ADAPTER_ADDRESSES aa = reinterpret_cast<PIP_ADAPTER_ADDRESSES>(aabuf);
							while (aa) {
								if (_deviceLuid.Value == aa->Luid.Value) {
									isBorked = (aa->OperStatus != IfOperStatusUp);
									break;
								}
								aa = aa->Next;
							}

							if (isBorked) {
								// Close and reopen tap device if there's an issue (outer loop)
								break;
							}
						}
					}
				}

				if ((waitResult == WAIT_TIMEOUT) || (waitResult == WAIT_FAILED)) {
					Sleep(250);	  // guard against spinning under some conditions
					continue;
				}

				if (HasOverlappedIoCompleted(&tapOvlRead)) {
					DWORD bytesRead = 0;
					if (GetOverlappedResult(_tap, &tapOvlRead, &bytesRead, FALSE)) {
						if ((bytesRead > 14) && (_enabled)) {
							MAC to(tapReadBuf, 6);
							MAC from(tapReadBuf + 6, 6);
							unsigned int etherType = ((((unsigned int)tapReadBuf[12]) & 0xff) << 8) | (((unsigned int)tapReadBuf[13]) & 0xff);
							try {
								_handler(_arg, (void*)0, _nwid, from, to, etherType, 0, tapReadBuf + 14, bytesRead - 14);
							}
							catch (...) {
							}	// handlers should not throw
						}
					}
					ReadFile(_tap, tapReadBuf, ZT_MAX_MTU + 32, NULL, &tapOvlRead);
				}

				if (writeInProgress) {
					if (HasOverlappedIoCompleted(&tapOvlWrite)) {
						writeInProgress = false;
						_injectPending_m.lock();
						_injectPending.pop();
					}
					else
						continue;	// still writing, so skip code below and wait
				}
				else
					_injectPending_m.lock();

				if (! _injectPending.empty()) {
					WriteFile(_tap, _injectPending.front().data, _injectPending.front().len, NULL, &tapOvlWrite);
					writeInProgress = true;
				}

				_injectPending_m.unlock();
			}

			CancelIo(_tap);

			CloseHandle(tapOvlRead.hEvent);
			CloseHandle(tapOvlWrite.hEvent);
			CloseHandle(_tap);
			_tap = INVALID_HANDLE_VALUE;

			// We will restart and re-open the tap unless _run == false
		}
	}
	catch (...) {
	}	// catch unexpected exceptions -- this should not happen but would prevent program crash or other weird issues since threads should not throw
	CoUninitialize();
}

NET_IFINDEX WindowsEthernetTap::_getDeviceIndex()
{
	MIB_IF_TABLE2* ift = (MIB_IF_TABLE2*)0;

	if (GetIfTable2Ex(MibIfTableRaw, &ift) != NO_ERROR)
		throw std::runtime_error("GetIfTable2Ex() failed");

	if (ift->NumEntries > 0) {
		for (ULONG i = 0; i < ift->NumEntries; ++i) {
			if (ift->Table[i].InterfaceLuid.Value == _deviceLuid.Value) {
				NET_IFINDEX idx = ift->Table[i].InterfaceIndex;
				FreeMibTable(ift);
				return idx;
			}
		}
	}

	FreeMibTable(&ift);

	throw std::runtime_error("interface not found");
}

std::vector<std::string> WindowsEthernetTap::_getRegistryIPv4Value(const char* regKey)
{
	std::vector<std::string> value;
	HKEY tcpIpInterfaces;
	if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\services\\Tcpip\\Parameters\\Interfaces", 0, KEY_READ | KEY_WRITE, &tcpIpInterfaces) == ERROR_SUCCESS) {
		char buf[16384];
		DWORD len = sizeof(buf);
		DWORD kt = REG_MULTI_SZ;
		if (RegGetValueA(tcpIpInterfaces, _netCfgInstanceId.c_str(), regKey, 0, &kt, &buf, &len) == ERROR_SUCCESS) {
			switch (kt) {
				case REG_SZ:
					if (len > 0)
						value.push_back(std::string(buf));
					break;
				case REG_MULTI_SZ: {
					for (DWORD k = 0, s = 0; k < len; ++k) {
						if (! buf[k]) {
							if (s < k) {
								value.push_back(std::string(buf + s));
								s = k + 1;
							}
							else
								break;
						}
					}
				} break;
			}
		}
		RegCloseKey(tcpIpInterfaces);
	}
	return value;
}

void WindowsEthernetTap::_setRegistryIPv4Value(const char* regKey, const std::vector<std::string>& value)
{
	std::string regMulti;
	for (std::vector<std::string>::const_iterator s(value.begin()); s != value.end(); ++s) {
		regMulti.append(*s);
		regMulti.push_back((char)0);
	}
	HKEY tcpIpInterfaces;
	if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\services\\Tcpip\\Parameters\\Interfaces", 0, KEY_READ | KEY_WRITE, &tcpIpInterfaces) == ERROR_SUCCESS) {
		if (regMulti.length() > 0) {
			regMulti.push_back((char)0);
			RegSetKeyValueA(tcpIpInterfaces, _netCfgInstanceId.c_str(), regKey, REG_MULTI_SZ, regMulti.data(), (DWORD)regMulti.length());
		}
		else {
			RegDeleteKeyValueA(tcpIpInterfaces, _netCfgInstanceId.c_str(), regKey);
		}
		RegCloseKey(tcpIpInterfaces);
	}
}

void WindowsEthernetTap::_syncIps()
{
	// assumes _assignedIps_m is locked

	if (! _initialized)
		return;

	std::vector<InetAddress> haveIps(ips());

	for (std::vector<InetAddress>::const_iterator aip(_assignedIps.begin()); aip != _assignedIps.end(); ++aip) {
		if (std::find(haveIps.begin(), haveIps.end(), *aip) == haveIps.end()) {
			MIB_UNICASTIPADDRESS_ROW ipr;

			InitializeUnicastIpAddressEntry(&ipr);
			if (aip->isV4()) {
				ipr.Address.Ipv4.sin_family = AF_INET;
				ipr.Address.Ipv4.sin_addr.S_un.S_addr = *((const uint32_t*)aip->rawIpData());
				ipr.OnLinkPrefixLength = aip->netmaskBits();
				if (ipr.OnLinkPrefixLength >= 32)
					continue;
			}
			else if (aip->isV6()) {
				ipr.Address.Ipv6.sin6_family = AF_INET6;
				memcpy(ipr.Address.Ipv6.sin6_addr.u.Byte, aip->rawIpData(), 16);
				ipr.OnLinkPrefixLength = aip->netmaskBits();
				if (ipr.OnLinkPrefixLength >= 128)
					continue;
			}
			else
				continue;

			ipr.PrefixOrigin = IpPrefixOriginManual;
			ipr.SuffixOrigin = IpSuffixOriginManual;
			ipr.ValidLifetime = 0xffffffff;
			ipr.PreferredLifetime = 0xffffffff;

			ipr.InterfaceLuid = _deviceLuid;
			ipr.InterfaceIndex = _getDeviceIndex();

			CreateUnicastIpAddressEntry(&ipr);
		}

		if (aip->isV4()) {
			char ipbuf[64];
			std::string ipStr(aip->toIpString(ipbuf));
			std::vector<std::string> regIps(_getRegistryIPv4Value("IPAddress"));
			if (std::find(regIps.begin(), regIps.end(), ipStr) == regIps.end()) {
				std::vector<std::string> regSubnetMasks(_getRegistryIPv4Value("SubnetMask"));
				regIps.push_back(ipStr);
				regSubnetMasks.push_back(aip->netmask().toIpString(ipbuf));
				_setRegistryIPv4Value("IPAddress", regIps);
				_setRegistryIPv4Value("SubnetMask", regSubnetMasks);
			}
		}
	}
}

void WindowsEthernetTap::setDns(const char* domain, const std::vector<InetAddress>& servers)
{
	WinDNSHelper::setDNS(_nwid, domain, servers);
}

}	// namespace ZeroTier
