tailscale/cmd/tailscaled/tailscaled.go
Naman Sood 5ea53891fe
cmd/tailscaled: populate netstack variable to use dialer in SOCKS5
Signed-off-by: Naman Sood <mail@nsood.in>
2021-04-14 13:13:10 -04:00

419 lines
12 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 tailscaled program is the Tailscale client daemon. It's configured
// and controlled via the tailscale CLI program.
//
// It primarily supports Linux, though other systems will likely be
// supported in the future.
package main // import "tailscale.com/cmd/tailscaled"
import (
"context"
"errors"
"flag"
"fmt"
"log"
"net"
"net/http"
"net/http/pprof"
"os"
"os/signal"
"runtime"
"runtime/debug"
"strconv"
"strings"
"sync"
"syscall"
"time"
"github.com/go-multierror/multierror"
"tailscale.com/ipn/ipnserver"
"tailscale.com/logpolicy"
"tailscale.com/net/dns"
"tailscale.com/net/socks5"
"tailscale.com/net/tstun"
"tailscale.com/paths"
"tailscale.com/types/flagtype"
"tailscale.com/types/logger"
"tailscale.com/types/netmap"
"tailscale.com/version"
"tailscale.com/version/distro"
"tailscale.com/wgengine"
"tailscale.com/wgengine/magicsock"
"tailscale.com/wgengine/monitor"
"tailscale.com/wgengine/netstack"
"tailscale.com/wgengine/router"
)
// globalStateKey is the ipn.StateKey that tailscaled loads on
// startup.
//
// We have to support multiple state keys for other OSes (Windows in
// particular), but right now Unix daemons run with a single
// node-global state. To keep open the option of having per-user state
// later, the global state key doesn't look like a username.
const globalStateKey = "_daemon"
// defaultTunName returns the default tun device name for the platform.
func defaultTunName() string {
switch runtime.GOOS {
case "openbsd":
return "tun"
case "windows":
return "Tailscale"
case "darwin":
// "utun" is recognized by wireguard-go/tun/tun_darwin.go
// as a magic value that uses/creates any free number.
return "utun"
case "linux":
if distro.Get() == distro.Synology {
// Try TUN, but fall back to userspace networking if needed.
// See https://github.com/tailscale/tailscale-synology/issues/35
return "tailscale0,userspace-networking"
}
}
return "tailscale0"
}
var args struct {
cleanup bool
debug string
tunname string // tun name, "userspace-networking", or comma-separated list thereof
port uint16
statepath string
socketpath string
verbose int
socksAddr string // listen address for SOCKS5 server
}
var (
installSystemDaemon func([]string) error // non-nil on some platforms
uninstallSystemDaemon func([]string) error // non-nil on some platforms
)
var subCommands = map[string]*func([]string) error{
"install-system-daemon": &installSystemDaemon,
"uninstall-system-daemon": &uninstallSystemDaemon,
"debug": &debugModeFunc,
}
func main() {
// We aren't very performance sensitive, and the parts that are
// performance sensitive (wireguard) try hard not to do any memory
// allocations. So let's be aggressive about garbage collection,
// unless the user specifically overrides it in the usual way.
if _, ok := os.LookupEnv("GOGC"); !ok {
debug.SetGCPercent(10)
}
printVersion := false
flag.IntVar(&args.verbose, "verbose", 0, "log verbosity level; 0 is default, 1 or higher are increasingly verbose")
flag.BoolVar(&args.cleanup, "cleanup", false, "clean up system state and exit")
flag.StringVar(&args.debug, "debug", "", "listen address ([ip]:port) of optional debug server")
flag.StringVar(&args.socksAddr, "socks5-server", "", `optional [ip]:port to run a SOCK5 server (e.g. "localhost:1080")`)
flag.StringVar(&args.tunname, "tun", defaultTunName(), `tunnel interface name; use "userspace-networking" (beta) to not use TUN`)
flag.Var(flagtype.PortValue(&args.port, magicsock.DefaultPort), "port", "UDP port to listen on for WireGuard and peer-to-peer traffic; 0 means automatically select")
flag.StringVar(&args.statepath, "state", paths.DefaultTailscaledStateFile(), "path of state file")
flag.StringVar(&args.socketpath, "socket", paths.DefaultTailscaledSocket(), "path of the service unix socket")
flag.BoolVar(&printVersion, "version", false, "print version information and exit")
if len(os.Args) > 1 {
sub := os.Args[1]
if fp, ok := subCommands[sub]; ok {
if *fp == nil {
log.SetFlags(0)
log.Fatalf("%s not available on %v", sub, runtime.GOOS)
}
if err := (*fp)(os.Args[2:]); err != nil {
log.SetFlags(0)
log.Fatal(err)
}
return
}
}
if beWindowsSubprocess() {
return
}
flag.Parse()
if flag.NArg() > 0 {
log.Fatalf("tailscaled does not take non-flag arguments: %q", flag.Args())
}
if printVersion {
fmt.Println(version.String())
os.Exit(0)
}
if runtime.GOOS == "darwin" && os.Getuid() != 0 && !strings.Contains(args.tunname, "userspace-networking") {
log.SetFlags(0)
log.Fatalf("tailscaled requires root; use sudo tailscaled (or use --tun=userspace-networking)")
}
if args.socketpath == "" && runtime.GOOS != "windows" {
log.SetFlags(0)
log.Fatalf("--socket is required")
}
if err := run(); err != nil {
// No need to log; the func already did
os.Exit(1)
}
}
func run() error {
var err error
pol := logpolicy.New("tailnode.log.tailscale.io")
pol.SetVerbosityLevel(args.verbose)
defer func() {
// Finish uploading logs after closing everything else.
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
pol.Shutdown(ctx)
}()
if isWindowsService() {
// Run the IPN server from the Windows service manager.
log.Printf("Running service...")
if err := runWindowsService(pol); err != nil {
log.Printf("runservice: %v", err)
}
log.Printf("Service ended.")
return nil
}
var logf logger.Logf = log.Printf
if v, _ := strconv.ParseBool(os.Getenv("TS_DEBUG_MEMORY")); v {
logf = logger.RusagePrefixLog(logf)
}
logf = logger.RateLimitedFn(logf, 5*time.Second, 5, 100)
if args.cleanup {
dns.Cleanup(logf, args.tunname)
router.Cleanup(logf, args.tunname)
return nil
}
if args.statepath == "" {
log.Fatalf("--state is required")
}
var debugMux *http.ServeMux
if args.debug != "" {
debugMux = newDebugMux()
go runDebugServer(debugMux, args.debug)
}
linkMon, err := monitor.New(logf)
if err != nil {
log.Fatalf("creating link monitor: %v", err)
}
pol.Logtail.SetLinkMonitor(linkMon)
var socksListener net.Listener
if args.socksAddr != "" {
var err error
socksListener, err = net.Listen("tcp", args.socksAddr)
if err != nil {
log.Fatalf("SOCKS5 listener: %v", err)
}
}
e, useNetstack, err := createEngine(logf, linkMon)
if err != nil {
logf("wgengine.New: %v", err)
return err
}
var ns *netstack.Impl
if useNetstack || wrapNetstack {
onlySubnets := wrapNetstack && !useNetstack
ns = mustStartNetstack(logf, e, onlySubnets)
}
if socksListener != nil {
srv := &socks5.Server{
Logf: logger.WithPrefix(logf, "socks5: "),
}
// TODO: also consider wrapNetstack, where dials can go to either Tailscale
// or non-Tailscale targets. But that's also basically what
// https://github.com/tailscale/tailscale/issues/1617 is about, so do them
// both at the same time.
if useNetstack {
srv.Dialer = func(ctx context.Context, network, addr string) (net.Conn, error) {
return ns.DialContextTCP(ctx, addr)
}
} else {
var mu sync.Mutex
var dns netstack.DNSMap
e.AddNetworkMapCallback(func(nm *netmap.NetworkMap) {
mu.Lock()
defer mu.Unlock()
dns = netstack.DNSMapFromNetworkMap(nm)
})
srv.Dialer = func(ctx context.Context, network, addr string) (net.Conn, error) {
ipp, err := dns.Resolve(ctx, addr)
if err != nil {
return nil, err
}
var d net.Dialer
return d.DialContext(ctx, network, ipp.String())
}
}
go func() {
log.Fatalf("SOCKS5 server exited: %v", srv.Serve(socksListener))
}()
}
e = wgengine.NewWatchdog(e)
ctx, cancel := context.WithCancel(context.Background())
// Exit gracefully by cancelling the ipnserver context in most common cases:
// interrupted from the TTY or killed by a service manager.
interrupt := make(chan os.Signal, 1)
signal.Notify(interrupt, syscall.SIGINT, syscall.SIGTERM)
// SIGPIPE sometimes gets generated when CLIs disconnect from
// tailscaled. The default action is to terminate the process, we
// want to keep running.
signal.Ignore(syscall.SIGPIPE)
go func() {
select {
case s := <-interrupt:
logf("tailscaled got signal %v; shutting down", s)
cancel()
case <-ctx.Done():
// continue
}
}()
opts := ipnserver.Options{
SocketPath: args.socketpath,
Port: 41112,
StatePath: args.statepath,
AutostartStateKey: globalStateKey,
SurviveDisconnects: true,
DebugMux: debugMux,
}
err = ipnserver.Run(ctx, logf, pol.PublicID.String(), ipnserver.FixedEngine(e), opts)
// Cancelation is not an error: it is the only way to stop ipnserver.
if err != nil && err != context.Canceled {
logf("ipnserver.Run: %v", err)
return err
}
return nil
}
func createEngine(logf logger.Logf, linkMon *monitor.Mon) (e wgengine.Engine, useNetstack bool, err error) {
if args.tunname == "" {
return nil, false, errors.New("no --tun value specified")
}
var errs []error
for _, name := range strings.Split(args.tunname, ",") {
logf("wgengine.NewUserspaceEngine(tun %q) ...", name)
e, useNetstack, err = tryEngine(logf, linkMon, name)
if err == nil {
return e, useNetstack, nil
}
logf("wgengine.NewUserspaceEngine(tun %q) error: %v", name, err)
errs = append(errs, err)
}
return nil, false, multierror.New(errs)
}
var wrapNetstack = shouldWrapNetstack()
func shouldWrapNetstack() bool {
if e := os.Getenv("TS_DEBUG_WRAP_NETSTACK"); e != "" {
v, err := strconv.ParseBool(e)
if err != nil {
log.Fatalf("invalid TS_DEBUG_WRAP_NETSTACK value: %v", err)
}
return v
}
if distro.Get() == distro.Synology {
return true
}
switch runtime.GOOS {
case "windows", "darwin":
// Enable on Windows and tailscaled-on-macOS (this doesn't
// affect the GUI clients).
return true
}
return false
}
func tryEngine(logf logger.Logf, linkMon *monitor.Mon, name string) (e wgengine.Engine, useNetstack bool, err error) {
conf := wgengine.Config{
ListenPort: args.port,
LinkMonitor: linkMon,
}
useNetstack = name == "userspace-networking"
if !useNetstack {
dev, devName, err := tstun.New(logf, name)
if err != nil {
tstun.Diagnose(logf, name)
return nil, false, err
}
conf.Tun = dev
r, err := router.New(logf, dev)
if err != nil {
dev.Close()
return nil, false, err
}
d, err := dns.NewOSConfigurator(logf, devName)
if err != nil {
return nil, false, err
}
conf.DNS = d
conf.Router = r
if wrapNetstack {
conf.Router = netstack.NewSubnetRouterWrapper(conf.Router)
}
}
e, err = wgengine.NewUserspaceEngine(logf, conf)
if err != nil {
return nil, useNetstack, err
}
return e, useNetstack, nil
}
func newDebugMux() *http.ServeMux {
mux := http.NewServeMux()
mux.HandleFunc("/debug/pprof/", pprof.Index)
mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
return mux
}
func runDebugServer(mux *http.ServeMux, addr string) {
srv := &http.Server{
Addr: addr,
Handler: mux,
}
if err := srv.ListenAndServe(); err != nil {
log.Fatal(err)
}
}
func mustStartNetstack(logf logger.Logf, e wgengine.Engine, onlySubnets bool) *netstack.Impl {
tunDev, magicConn, ok := e.(wgengine.InternalsGetter).GetInternals()
if !ok {
log.Fatalf("%T is not a wgengine.InternalsGetter", e)
}
ns, err := netstack.Create(logf, tunDev, e, magicConn, onlySubnets)
if err != nil {
log.Fatalf("netstack.Create: %v", err)
}
if err := ns.Start(); err != nil {
log.Fatalf("failed to start netstack: %v", err)
}
return ns
}