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