mirror of
https://github.com/tailscale/tailscale.git
synced 2024-11-26 11:35:35 +00:00
279 lines
6.8 KiB
Go
279 lines
6.8 KiB
Go
// 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.
|
|
|
|
// The derper binary is a simple DERP server.
|
|
package main // import "tailscale.com/cmd/derper"
|
|
|
|
import (
|
|
"context"
|
|
"encoding/json"
|
|
"errors"
|
|
"expvar"
|
|
"flag"
|
|
"fmt"
|
|
"io"
|
|
"io/ioutil"
|
|
"log"
|
|
"net"
|
|
"net/http"
|
|
"os"
|
|
"path/filepath"
|
|
"regexp"
|
|
"time"
|
|
|
|
"github.com/tailscale/wireguard-go/wgcfg"
|
|
"golang.org/x/crypto/acme/autocert"
|
|
"tailscale.com/atomicfile"
|
|
"tailscale.com/derp"
|
|
"tailscale.com/derp/derphttp"
|
|
"tailscale.com/logpolicy"
|
|
"tailscale.com/metrics"
|
|
"tailscale.com/stun"
|
|
"tailscale.com/tsweb"
|
|
"tailscale.com/types/key"
|
|
)
|
|
|
|
var (
|
|
dev = flag.Bool("dev", false, "run in localhost development mode")
|
|
addr = flag.String("a", ":443", "server address")
|
|
configPath = flag.String("c", "", "config file path")
|
|
certDir = flag.String("certdir", tsweb.DefaultCertDir("derper-certs"), "directory to store LetsEncrypt certs, if addr's port is :443")
|
|
hostname = flag.String("hostname", "derp.tailscale.com", "LetsEncrypt host name, if addr's port is :443")
|
|
logCollection = flag.String("logcollection", "", "If non-empty, logtail collection to log to")
|
|
runSTUN = flag.Bool("stun", false, "also run a STUN server")
|
|
)
|
|
|
|
type config struct {
|
|
PrivateKey wgcfg.PrivateKey
|
|
}
|
|
|
|
func loadConfig() config {
|
|
if *dev {
|
|
return config{PrivateKey: mustNewKey()}
|
|
}
|
|
if *configPath == "" {
|
|
log.Fatalf("derper: -c <config path> not specified")
|
|
}
|
|
b, err := ioutil.ReadFile(*configPath)
|
|
switch {
|
|
case os.IsNotExist(err):
|
|
return writeNewConfig()
|
|
case err != nil:
|
|
log.Fatal(err)
|
|
panic("unreachable")
|
|
default:
|
|
var cfg config
|
|
if err := json.Unmarshal(b, &cfg); err != nil {
|
|
log.Fatalf("derper: config: %v", err)
|
|
}
|
|
return cfg
|
|
}
|
|
}
|
|
|
|
func mustNewKey() wgcfg.PrivateKey {
|
|
key, err := wgcfg.NewPrivateKey()
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
return key
|
|
}
|
|
|
|
func writeNewConfig() config {
|
|
key := mustNewKey()
|
|
if err := os.MkdirAll(filepath.Dir(*configPath), 0777); err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
cfg := config{
|
|
PrivateKey: key,
|
|
}
|
|
b, err := json.MarshalIndent(cfg, "", "\t")
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
if err := atomicfile.WriteFile(*configPath, b, 0666); err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
return cfg
|
|
}
|
|
|
|
func main() {
|
|
flag.Parse()
|
|
|
|
if *dev {
|
|
*logCollection = ""
|
|
*addr = ":3340" // above the keys DERP
|
|
log.Printf("Running in dev mode.")
|
|
tsweb.DevMode = true
|
|
}
|
|
|
|
var logPol *logpolicy.Policy
|
|
if *logCollection != "" {
|
|
logPol = logpolicy.New(*logCollection)
|
|
log.SetOutput(logPol.Logtail)
|
|
}
|
|
|
|
cfg := loadConfig()
|
|
|
|
letsEncrypt := tsweb.IsProd443(*addr)
|
|
|
|
s := derp.NewServer(key.Private(cfg.PrivateKey), log.Printf)
|
|
expvar.Publish("derp", s.ExpVar())
|
|
|
|
// Create our own mux so we don't expose /debug/ stuff to the world.
|
|
mux := tsweb.NewMux(debugHandler(s))
|
|
mux.Handle("/derp", derphttp.Handler(s))
|
|
mux.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
|
|
w.Header().Set("Content-Type", "text/html; charset=utf-8")
|
|
w.WriteHeader(200)
|
|
io.WriteString(w, `<html><body>
|
|
<h1>DERP</h1>
|
|
<p>
|
|
This is a
|
|
<a href="https://tailscale.com/">Tailscale</a>
|
|
<a href="https://godoc.org/tailscale.com/derp">DERP</a>
|
|
server.
|
|
</p>
|
|
`)
|
|
if tsweb.AllowDebugAccess(r) {
|
|
io.WriteString(w, "<p>Debug info at <a href='/debug/'>/debug/</a>.</p>\n")
|
|
}
|
|
}))
|
|
|
|
if *runSTUN {
|
|
go serveSTUN()
|
|
}
|
|
|
|
httpsrv := &http.Server{
|
|
Addr: *addr,
|
|
Handler: mux,
|
|
}
|
|
|
|
var err error
|
|
if letsEncrypt {
|
|
if *certDir == "" {
|
|
log.Fatalf("missing required --certdir flag")
|
|
}
|
|
log.Printf("derper: serving on %s with TLS", *addr)
|
|
certManager := &autocert.Manager{
|
|
Prompt: autocert.AcceptTOS,
|
|
HostPolicy: autocert.HostWhitelist(*hostname),
|
|
Cache: autocert.DirCache(*certDir),
|
|
}
|
|
if *hostname == "derp.tailscale.com" {
|
|
certManager.HostPolicy = prodAutocertHostPolicy
|
|
certManager.Email = "security@tailscale.com"
|
|
}
|
|
httpsrv.TLSConfig = certManager.TLSConfig()
|
|
go func() {
|
|
err := http.ListenAndServe(":80", certManager.HTTPHandler(tsweb.Port80Handler{mux}))
|
|
if err != nil {
|
|
if err != http.ErrServerClosed {
|
|
log.Fatal(err)
|
|
}
|
|
}
|
|
}()
|
|
err = httpsrv.ListenAndServeTLS("", "")
|
|
} else {
|
|
log.Printf("derper: serving on %s", *addr)
|
|
err = httpsrv.ListenAndServe()
|
|
}
|
|
if err != nil && err != http.ErrServerClosed {
|
|
log.Fatalf("derper: %v", err)
|
|
}
|
|
}
|
|
|
|
func debugHandler(s *derp.Server) http.Handler {
|
|
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
|
|
f := func(format string, args ...interface{}) { fmt.Fprintf(w, format, args...) }
|
|
f(`<html><body>
|
|
<h1>DERP debug</h1>
|
|
<ul>
|
|
`)
|
|
f("<li><b>Hostname:</b> %v</li>\n", *hostname)
|
|
f("<li><b>Uptime:</b> %v</li>\n", tsweb.Uptime())
|
|
|
|
f(`<li><a href="/debug/vars">/debug/vars</a> (Go)</li>
|
|
<li><a href="/debug/varz">/debug/varz</a> (Prometheus)</li>
|
|
<li><a href="/debug/pprof/">/debug/pprof/</a></li>
|
|
<li><a href="/debug/pprof/goroutine?debug=1">/debug/pprof/goroutine</a> (collapsed)</li>
|
|
<li><a href="/debug/pprof/goroutine?debug=2">/debug/pprof/goroutine</a> (full)</li>
|
|
<ul>
|
|
</html>
|
|
`)
|
|
})
|
|
}
|
|
|
|
func serveSTUN() {
|
|
pc, err := net.ListenPacket("udp", ":3478")
|
|
if err != nil {
|
|
log.Fatalf("failed to open STUN listener: %v", err)
|
|
}
|
|
log.Printf("running STUN server on %v", pc.LocalAddr())
|
|
|
|
var (
|
|
stats = new(metrics.Set)
|
|
stunDisposition = &metrics.LabelMap{Label: "disposition"}
|
|
stunAddrFamily = &metrics.LabelMap{Label: "family"}
|
|
|
|
stunReadError = stunDisposition.Get("read_error")
|
|
stunNotSTUN = stunDisposition.Get("not_stun")
|
|
stunWriteError = stunDisposition.Get("write_error")
|
|
stunSuccess = stunDisposition.Get("success")
|
|
|
|
stunIPv4 = stunAddrFamily.Get("ipv4")
|
|
stunIPv6 = stunAddrFamily.Get("ipv6")
|
|
)
|
|
stats.Set("counter_requests", stunDisposition)
|
|
stats.Set("counter_addrfamily", stunAddrFamily)
|
|
expvar.Publish("stun", stats)
|
|
|
|
var buf [64 << 10]byte
|
|
for {
|
|
n, addr, err := pc.ReadFrom(buf[:])
|
|
if err != nil {
|
|
log.Printf("STUN ReadFrom: %v", err)
|
|
time.Sleep(time.Second)
|
|
stunReadError.Add(1)
|
|
continue
|
|
}
|
|
ua, ok := addr.(*net.UDPAddr)
|
|
if !ok {
|
|
log.Printf("STUN unexpected address %T %v", addr, addr)
|
|
stunReadError.Add(1)
|
|
continue
|
|
}
|
|
pkt := buf[:n]
|
|
if !stun.Is(pkt) {
|
|
stunNotSTUN.Add(1)
|
|
continue
|
|
}
|
|
txid, err := stun.ParseBindingRequest(pkt)
|
|
if err != nil {
|
|
stunNotSTUN.Add(1)
|
|
continue
|
|
}
|
|
if ua.IP.To4() != nil {
|
|
stunIPv4.Add(1)
|
|
} else {
|
|
stunIPv6.Add(1)
|
|
}
|
|
res := stun.Response(txid, ua.IP, uint16(ua.Port))
|
|
_, err = pc.WriteTo(res, addr)
|
|
if err != nil {
|
|
stunWriteError.Add(1)
|
|
} else {
|
|
stunSuccess.Add(1)
|
|
}
|
|
}
|
|
}
|
|
|
|
var validProdHostname = regexp.MustCompile(`^derp(\d+|\-\w+)?\.tailscale\.com\.?$`)
|
|
|
|
func prodAutocertHostPolicy(_ context.Context, host string) error {
|
|
if validProdHostname.MatchString(host) {
|
|
return nil
|
|
}
|
|
return errors.New("invalid hostname")
|
|
}
|