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tailscale/net/tshttpproxy/tshttpproxy_synology.go

143 lines
3.1 KiB
Go

// Copyright (c) 2022 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.
//go:build linux
// +build linux
package tshttpproxy
import (
"bytes"
"fmt"
"io"
"net"
"net/http"
"net/url"
"os"
"strings"
"sync"
"time"
"tailscale.com/util/lineread"
)
// These vars are overridden for tests.
var (
synologyProxyConfigPath = "/etc/proxy.conf"
openSynologyProxyConf = func() (io.ReadCloser, error) {
return os.Open(synologyProxyConfigPath)
}
)
var cache struct {
sync.Mutex
httpProxy *url.URL
httpsProxy *url.URL
updated time.Time
}
func synologyProxyFromConfigCached(req *http.Request) (*url.URL, error) {
if req.URL == nil {
return nil, nil
}
cache.Lock()
defer cache.Unlock()
var err error
modtime := mtime(synologyProxyConfigPath)
if modtime != cache.updated {
cache.httpProxy, cache.httpsProxy, err = synologyProxiesFromConfig()
cache.updated = modtime
}
if req.URL.Scheme == "https" {
return cache.httpsProxy, err
}
return cache.httpProxy, err
}
func synologyProxiesFromConfig() (*url.URL, *url.URL, error) {
r, err := openSynologyProxyConf()
if err != nil {
if os.IsNotExist(err) {
return nil, nil, nil
}
return nil, nil, err
}
defer r.Close()
return parseSynologyConfig(r)
}
// parseSynologyConfig parses the Synology proxy configuration, and returns any
// http proxy, and any https proxy respectively, or an error if parsing fails.
func parseSynologyConfig(r io.Reader) (*url.URL, *url.URL, error) {
cfg := map[string]string{}
if err := lineread.Reader(r, func(line []byte) error {
// accept and skip over empty lines
line = bytes.TrimSpace(line)
if len(line) == 0 {
return nil
}
key, value, ok := strings.Cut(string(line), "=")
if !ok {
return fmt.Errorf("missing \"=\" in proxy.conf line: %q", line)
}
cfg[string(key)] = string(value)
return nil
}); err != nil {
return nil, nil, err
}
if cfg["proxy_enabled"] != "yes" {
return nil, nil, nil
}
httpProxyURL := new(url.URL)
httpsProxyURL := new(url.URL)
if cfg["auth_enabled"] == "yes" {
httpProxyURL.User = url.UserPassword(cfg["proxy_user"], cfg["proxy_pwd"])
httpsProxyURL.User = url.UserPassword(cfg["proxy_user"], cfg["proxy_pwd"])
}
// As far as we are aware, synology does not support tls proxies.
httpProxyURL.Scheme = "http"
httpsProxyURL.Scheme = "http"
httpsProxyURL = addHostPort(httpsProxyURL, cfg["https_host"], cfg["https_port"])
httpProxyURL = addHostPort(httpProxyURL, cfg["http_host"], cfg["http_port"])
return httpProxyURL, httpsProxyURL, nil
}
// addHostPort adds to u the given host and port and returns the updated url, or
// if host is empty, it returns nil.
func addHostPort(u *url.URL, host, port string) *url.URL {
if host == "" {
return nil
}
if port == "" {
u.Host = host
} else {
u.Host = net.JoinHostPort(host, port)
}
return u
}
// mtime stat's path and returns its modification time. If path does not exist,
// it returns the unix epoch.
func mtime(path string) time.Time {
fi, err := os.Stat(path)
if err != nil {
return time.Unix(0, 0)
}
return fi.ModTime()
}