mirror of https://github.com/tailscale/tailscale/
net/tshttpproxy: new package, support WPAD/PAC proxies on Windows
Updates tailscale/corp#553 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>pull/692/head
Brad Fitzpatrick
4 years ago
parent
1835bb6f85
commit
c5eb57f4d6
@ -0,0 +1,33 @@
|
||||
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
// Package tshttpproxy contains Tailscale additions to httpproxy not available
|
||||
// in golang.org/x/net/http/httpproxy. Notably, it aims to support Windows better.
|
||||
package tshttpproxy
|
||||
|
||||
import (
|
||||
"net/http"
|
||||
"net/url"
|
||||
)
|
||||
|
||||
// sysProxyFromEnv, if non-nil, specifies a platform-specific ProxyFromEnvironment
|
||||
// func to use if http.ProxyFromEnvironment doesn't return a proxy.
|
||||
// For example, WPAD PAC files on Windows.
|
||||
var sysProxyFromEnv func(*http.Request) (*url.URL, error)
|
||||
|
||||
func ProxyFromEnvironment(req *http.Request) (*url.URL, error) {
|
||||
u, err := http.ProxyFromEnvironment(req)
|
||||
if u != nil && err == nil {
|
||||
return u, nil
|
||||
}
|
||||
|
||||
if sysProxyFromEnv != nil {
|
||||
u, err := sysProxyFromEnv(req)
|
||||
if u != nil && err == nil {
|
||||
return u, nil
|
||||
}
|
||||
}
|
||||
|
||||
return nil, err
|
||||
}
|
||||
@ -0,0 +1,142 @@
|
||||
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
package tshttpproxy
|
||||
|
||||
import (
|
||||
"log"
|
||||
"net/http"
|
||||
"net/url"
|
||||
"strings"
|
||||
"syscall"
|
||||
"unsafe"
|
||||
|
||||
"golang.org/x/sys/windows"
|
||||
)
|
||||
|
||||
var (
|
||||
winHTTP = windows.NewLazySystemDLL("winhttp.dll")
|
||||
httpOpenProc = winHTTP.NewProc("WinHttpOpen")
|
||||
closeHandleProc = winHTTP.NewProc("WinHttpCloseHandle")
|
||||
getProxyForUrlProc = winHTTP.NewProc("WinHttpGetProxyForUrl")
|
||||
)
|
||||
|
||||
func init() {
|
||||
sysProxyFromEnv = proxyFromWinHTTP
|
||||
}
|
||||
|
||||
func proxyFromWinHTTP(req *http.Request) (*url.URL, error) {
|
||||
if req.URL == nil {
|
||||
return nil, nil
|
||||
}
|
||||
urlStr := req.URL.String()
|
||||
|
||||
whi, err := winHTTPOpen()
|
||||
if err != nil {
|
||||
// Log but otherwise ignore the error.
|
||||
log.Printf("winhttp: Open: %v", err)
|
||||
return nil, nil
|
||||
}
|
||||
defer whi.Close()
|
||||
|
||||
v, err := whi.GetProxyForURL(urlStr)
|
||||
if err != nil {
|
||||
// See https://docs.microsoft.com/en-us/windows/win32/winhttp/error-messages
|
||||
const ERROR_WINHTTP_AUTODETECTION_FAILED = 12180
|
||||
if err == syscall.Errno(ERROR_WINHTTP_AUTODETECTION_FAILED) {
|
||||
return nil, nil
|
||||
}
|
||||
log.Printf("winhttp: GetProxyForURL(%q): %v (%T, %#v)", urlStr, err, err, err)
|
||||
return nil, nil
|
||||
}
|
||||
if v != "" {
|
||||
if !strings.HasPrefix(v, "https://") {
|
||||
v = "http://" + v
|
||||
}
|
||||
if u, err := url.Parse(v); err == nil {
|
||||
return u, nil
|
||||
}
|
||||
}
|
||||
|
||||
return nil, nil
|
||||
}
|
||||
|
||||
var userAgent = windows.StringToUTF16Ptr("Tailscale")
|
||||
|
||||
const (
|
||||
winHTTP_ACCESS_TYPE_AUTOMATIC_PROXY = 4
|
||||
winHTTP_AUTOPROXY_ALLOW_AUTOCONFIG = 0x00000100
|
||||
winHTTP_AUTOPROXY_AUTO_DETECT = 1
|
||||
winHTTP_AUTO_DETECT_TYPE_DHCP = 0x00000001
|
||||
winHTTP_AUTO_DETECT_TYPE_DNS_A = 0x00000002
|
||||
)
|
||||
|
||||
func winHTTPOpen() (winHTTPInternet, error) {
|
||||
if err := httpOpenProc.Find(); err != nil {
|
||||
return 0, err
|
||||
}
|
||||
r, _, err := httpOpenProc.Call(
|
||||
uintptr(unsafe.Pointer(userAgent)),
|
||||
winHTTP_ACCESS_TYPE_AUTOMATIC_PROXY,
|
||||
0, /* WINHTTP_NO_PROXY_NAME */
|
||||
0, /* WINHTTP_NO_PROXY_BYPASS */
|
||||
0)
|
||||
if r == 0 {
|
||||
return 0, err
|
||||
}
|
||||
return winHTTPInternet(r), nil
|
||||
}
|
||||
|
||||
type winHTTPInternet windows.Handle
|
||||
|
||||
func (hi winHTTPInternet) Close() error {
|
||||
if err := closeHandleProc.Find(); err != nil {
|
||||
return err
|
||||
}
|
||||
r, _, err := closeHandleProc.Call(uintptr(hi))
|
||||
if r == 1 {
|
||||
return nil
|
||||
}
|
||||
return err
|
||||
}
|
||||
|
||||
// WINHTTP_AUTOPROXY_OPTIONS
|
||||
// https://docs.microsoft.com/en-us/windows/win32/api/winhttp/ns-winhttp-winhttp_autoproxy_options
|
||||
type autoProxyOptions struct {
|
||||
DwFlags uint32
|
||||
DwAutoDetectFlags uint32
|
||||
AutoConfigUrl *uint16
|
||||
_ uintptr
|
||||
_ uint32
|
||||
FAutoLogonIfChallenged bool
|
||||
}
|
||||
|
||||
// WINHTTP_PROXY_INFO
|
||||
// https://docs.microsoft.com/en-us/windows/win32/api/winhttp/ns-winhttp-winhttp_proxy_info
|
||||
type winHTTPProxyInfo struct {
|
||||
AccessType uint16
|
||||
Proxy *uint16
|
||||
ProxyBypass *uint16
|
||||
}
|
||||
|
||||
var proxyForURLOpts = &autoProxyOptions{
|
||||
DwFlags: winHTTP_AUTOPROXY_ALLOW_AUTOCONFIG | winHTTP_AUTOPROXY_AUTO_DETECT,
|
||||
DwAutoDetectFlags: winHTTP_AUTO_DETECT_TYPE_DHCP, // | winHTTP_AUTO_DETECT_TYPE_DNS_A,
|
||||
}
|
||||
|
||||
func (hi winHTTPInternet) GetProxyForURL(urlStr string) (string, error) {
|
||||
if err := getProxyForUrlProc.Find(); err != nil {
|
||||
return "", err
|
||||
}
|
||||
var out winHTTPProxyInfo
|
||||
r, _, err := getProxyForUrlProc.Call(
|
||||
uintptr(hi),
|
||||
uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(urlStr))),
|
||||
uintptr(unsafe.Pointer(proxyForURLOpts)),
|
||||
uintptr(unsafe.Pointer(&out)))
|
||||
if r == 1 {
|
||||
return windows.UTF16PtrToString(out.Proxy), nil
|
||||
}
|
||||
return "", err
|
||||
}
|
||||
Loading…
Reference in New Issue