1 files changed, 230 insertions, 0 deletions
diff --git a/updater/winhttp/winhttp.go b/updater/winhttp/winhttp.go
new file mode 100644
index 00000000..cb19f194
--- /dev/null
+++ b/updater/winhttp/winhttp.go
@@ -0,0 +1,230 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2022 WireGuard LLC. All Rights Reserved.
+ */
+
+package winhttp
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync/atomic"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+type Session struct {
+	handle _HINTERNET
+}
+
+type Connection struct {
+	handle  _HINTERNET
+	session *Session
+	https   bool
+}
+
+type Response struct {
+	handle     _HINTERNET
+	connection *Connection
+}
+
+func convertError(err *error) {
+	if *err == nil {
+		return
+	}
+	var errno windows.Errno
+	if errors.As(*err, &errno) {
+		if errno > _WINHTTP_ERROR_BASE && errno <= _WINHTTP_ERROR_LAST {
+			*err = Error(errno)
+		}
+	}
+}
+
+func isWin7() bool {
+	maj, min, _ := windows.RtlGetNtVersionNumbers()
+	return maj < 6 || (maj == 6 && min <= 1)
+}
+
+func isWin8DotZeroOrBelow() bool {
+	maj, min, _ := windows.RtlGetNtVersionNumbers()
+	return maj < 6 || (maj == 6 && min <= 2)
+}
+
+func NewSession(userAgent string) (session *Session, err error) {
+	session = new(Session)
+	defer convertError(&err)
+	defer func() {
+		if err != nil {
+			session.Close()
+			session = nil
+		}
+	}()
+	userAgent16, err := windows.UTF16PtrFromString(userAgent)
+	if err != nil {
+		return
+	}
+	var proxyFlag uint32 = _WINHTTP_ACCESS_TYPE_AUTOMATIC_PROXY
+	if isWin7() {
+		proxyFlag = _WINHTTP_ACCESS_TYPE_DEFAULT_PROXY
+	}
+	session.handle, err = winHttpOpen(userAgent16, proxyFlag, nil, nil, 0)
+	if err != nil {
+		return
+	}
+	var enableHttp2 uint32 = _WINHTTP_PROTOCOL_FLAG_HTTP2
+	_ = winHttpSetOption(session.handle, _WINHTTP_OPTION_ENABLE_HTTP_PROTOCOL, unsafe.Pointer(&enableHttp2), uint32(unsafe.Sizeof(enableHttp2))) // Don't check return value, in case of old Windows
+
+	if isWin8DotZeroOrBelow() {
+		var enableTLS12 uint32 = _WINHTTP_FLAG_SECURE_PROTOCOL_TLS1_2
+		err = winHttpSetOption(session.handle, _WINHTTP_OPTION_SECURE_PROTOCOLS, unsafe.Pointer(&enableTLS12), uint32(unsafe.Sizeof(enableTLS12)))
+		if err != nil {
+			return
+		}
+	}
+
+	runtime.SetFinalizer(session, func(session *Session) {
+		session.Close()
+	})
+	return
+}
+
+func (session *Session) Close() (err error) {
+	defer convertError(&err)
+	handle := (_HINTERNET)(atomic.SwapUintptr((*uintptr)(&session.handle), 0))
+	if handle == 0 {
+		return
+	}
+	return winHttpCloseHandle(handle)
+}
+
+func (session *Session) Connect(server string, port uint16, https bool) (connection *Connection, err error) {
+	connection = &Connection{session: session}
+	defer convertError(&err)
+	defer func() {
+		if err != nil {
+			connection.Close()
+			connection = nil
+		}
+	}()
+	server16, err := windows.UTF16PtrFromString(server)
+	if err != nil {
+		return
+	}
+	connection.handle, err = winHttpConnect(session.handle, server16, port, 0)
+	if err != nil {
+		return
+	}
+	connection.https = https
+
+	runtime.SetFinalizer(connection, func(connection *Connection) {
+		connection.Close()
+	})
+	return
+}
+
+func (connection *Connection) Close() (err error) {
+	defer convertError(&err)
+	handle := (_HINTERNET)(atomic.SwapUintptr((*uintptr)(&connection.handle), 0))
+	if handle == 0 {
+		return
+	}
+	return winHttpCloseHandle(handle)
+}
+
+func (connection *Connection) Get(path string, refresh bool) (response *Response, err error) {
+	response = &Response{connection: connection}
+	defer convertError(&err)
+	defer func() {
+		if err != nil {
+			response.Close()
+			response = nil
+		}
+	}()
+	var flags uint32
+	if refresh {
+		flags |= _WINHTTP_FLAG_REFRESH
+	}
+	if connection.https {
+		flags |= _WINHTTP_FLAG_SECURE
+	}
+	path16, err := windows.UTF16PtrFromString(path)
+	if err != nil {
+		return
+	}
+	get16, err := windows.UTF16PtrFromString("GET")
+	if err != nil {
+		return
+	}
+	response.handle, err = winHttpOpenRequest(connection.handle, get16, path16, nil, nil, nil, flags)
+	if err != nil {
+		return
+	}
+	err = winHttpSendRequest(response.handle, nil, 0, nil, 0, 0, 0)
+	if err != nil {
+		return
+	}
+	err = winHttpReceiveResponse(response.handle, 0)
+	if err != nil {
+		return
+	}
+
+	runtime.SetFinalizer(response, func(response *Response) {
+		response.Close()
+	})
+	return
+}
+
+func (response *Response) Length() (length uint64, err error) {
+	defer convertError(&err)
+	numBuf := make([]uint16, 22)
+	numLen := uint32(len(numBuf) * 2)
+	err = winHttpQueryHeaders(response.handle, _WINHTTP_QUERY_CONTENT_LENGTH, nil, unsafe.Pointer(&numBuf[0]), &numLen, nil)
+	if err != nil {
+		return
+	}
+	length, err = strconv.ParseUint(windows.UTF16ToString(numBuf[:numLen]), 10, 64)
+	if err != nil {
+		return
+	}
+	return
+}
+
+func (response *Response) Read(p []byte) (n int, err error) {
+	defer convertError(&err)
+	if len(p) == 0 {
+		return 0, nil
+	}
+	var bytesRead uint32
+	err = winHttpReadData(response.handle, &p[0], uint32(len(p)), &bytesRead)
+	if err != nil {
+		return 0, nil
+	}
+	if bytesRead == 0 || int(bytesRead) < 0 {
+		return 0, io.EOF
+	}
+	return int(bytesRead), nil
+}
+
+func (response *Response) Close() (err error) {
+	defer convertError(&err)
+	handle := (_HINTERNET)(atomic.SwapUintptr((*uintptr)(&response.handle), 0))
+	if handle == 0 {
+		return
+	}
+	return winHttpCloseHandle(handle)
+}
+
+func (error Error) Error() string {
+	var message [2048]uint16
+	n, err := windows.FormatMessage(windows.FORMAT_MESSAGE_FROM_HMODULE|windows.FORMAT_MESSAGE_IGNORE_INSERTS|windows.FORMAT_MESSAGE_MAX_WIDTH_MASK,
+		modwinhttp.Handle(), uint32(error), 0, message[:], nil)
+	if err != nil {
+		return fmt.Sprintf("WinHTTP error #%d", error)
+	}
+	return strings.TrimSpace(windows.UTF16ToString(message[:n]))
+}