mirror of
https://github.com/tailscale/tailscale.git
synced 2024-12-14 04:04:42 +00:00
b1fff4499f
In a partially initialized state, we should cleanup all prior resources when an error occurs. Signed-off-by: Joe Tsai <joetsai@digital-static.net>
548 lines
14 KiB
Go
548 lines
14 KiB
Go
// Copyright (c) 2021 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 tsnet provides Tailscale as a library.
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//
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// It is an experimental work in progress.
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package tsnet
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import (
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"context"
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"net"
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"net/http"
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"net/netip"
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"os"
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"path/filepath"
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"strings"
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"sync"
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"time"
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"tailscale.com/client/tailscale"
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"tailscale.com/control/controlclient"
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"tailscale.com/envknob"
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"tailscale.com/hostinfo"
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"tailscale.com/ipn"
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"tailscale.com/ipn/ipnlocal"
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"tailscale.com/ipn/localapi"
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"tailscale.com/ipn/store"
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"tailscale.com/ipn/store/mem"
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"tailscale.com/logpolicy"
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"tailscale.com/logtail"
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"tailscale.com/logtail/filch"
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"tailscale.com/net/nettest"
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"tailscale.com/net/tsdial"
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"tailscale.com/smallzstd"
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"tailscale.com/types/logger"
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"tailscale.com/wgengine"
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"tailscale.com/wgengine/monitor"
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"tailscale.com/wgengine/netstack"
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)
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// Server is an embedded Tailscale server.
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//
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// Its exported fields may be changed until the first call to Listen.
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type Server struct {
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// Dir specifies the name of the directory to use for
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// state. If empty, a directory is selected automatically
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// under os.UserConfigDir (https://golang.org/pkg/os/#UserConfigDir).
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// based on the name of the binary.
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Dir string
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// Store specifies the state store to use.
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//
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// If nil, a new FileStore is initialized at `Dir/tailscaled.state`.
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// See tailscale.com/ipn/store for supported stores.
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//
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// Logs will automatically be uploaded to uploaded to log.tailscale.io,
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// where the configuration file for logging will be saved at
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// `Dir/tailscaled.log.conf`.
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Store ipn.StateStore
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// Hostname is the hostname to present to the control server.
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// If empty, the binary name is used.
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Hostname string
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// Logf, if non-nil, specifies the logger to use. By default,
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// log.Printf is used.
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Logf logger.Logf
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// Ephemeral, if true, specifies that the instance should register
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// as an Ephemeral node (https://tailscale.com/kb/1111/ephemeral-nodes/).
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Ephemeral bool
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// AuthKey, if non-empty, is the auth key to create the node
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// and will be preferred over the TS_AUTHKEY environment
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// variable. If the node is already created (from state
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// previously stored in in Store), then this field is not
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// used.
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AuthKey string
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initOnce sync.Once
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initErr error
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lb *ipnlocal.LocalBackend
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linkMon *monitor.Mon
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localAPIListener net.Listener
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rootPath string // the state directory
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hostname string
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shutdownCtx context.Context
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shutdownCancel context.CancelFunc
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localClient *tailscale.LocalClient
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logbuffer *filch.Filch
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logtail *logtail.Logger
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mu sync.Mutex
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listeners map[listenKey]*listener
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dialer *tsdial.Dialer
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}
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// Dial connects to the address on the tailnet.
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// It will start the server if it has not been started yet.
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func (s *Server) Dial(ctx context.Context, network, address string) (net.Conn, error) {
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if err := s.Start(); err != nil {
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return nil, err
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}
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return s.dialer.UserDial(ctx, network, address)
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}
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// LocalClient returns a LocalClient that speaks to s.
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//
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// It will start the server if it has not been started yet. If the server's
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// already been started successfully, it doesn't return an error.
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func (s *Server) LocalClient() (*tailscale.LocalClient, error) {
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if err := s.Start(); err != nil {
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return nil, err
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}
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return s.localClient, nil
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}
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// Start connects the server to the tailnet.
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// Optional: any calls to Dial/Listen will also call Start.
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func (s *Server) Start() error {
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hostinfo.SetPackage("tsnet")
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s.initOnce.Do(s.doInit)
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return s.initErr
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}
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// Close stops the server.
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//
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// It must not be called before or concurrently with Start.
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func (s *Server) Close() error {
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ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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var wg sync.WaitGroup
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wg.Add(1)
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go func() {
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defer wg.Done()
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// Perform a best-effort final flush.
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s.logtail.Shutdown(ctx)
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s.logbuffer.Close()
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}()
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if _, isMemStore := s.Store.(*mem.Store); isMemStore && s.Ephemeral {
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wg.Add(1)
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go func() {
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defer wg.Done()
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// Perform a best-effort logout.
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s.lb.LogoutSync(ctx)
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}()
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}
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s.shutdownCancel()
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s.lb.Shutdown()
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s.linkMon.Close()
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s.dialer.Close()
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s.localAPIListener.Close()
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s.mu.Lock()
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defer s.mu.Unlock()
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for _, ln := range s.listeners {
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ln.Close()
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}
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s.listeners = nil
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wg.Wait()
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return nil
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}
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func (s *Server) doInit() {
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s.shutdownCtx, s.shutdownCancel = context.WithCancel(context.Background())
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if err := s.start(); err != nil {
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s.initErr = fmt.Errorf("tsnet: %w", err)
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}
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}
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func (s *Server) getAuthKey() string {
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if v := s.AuthKey; v != "" {
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return v
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}
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return os.Getenv("TS_AUTHKEY")
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}
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func (s *Server) start() (reterr error) {
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var closePool closeOnErrorPool
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defer closePool.closeAllIfError(&reterr)
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exe, err := os.Executable()
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if err != nil {
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return err
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}
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prog := strings.TrimSuffix(strings.ToLower(filepath.Base(exe)), ".exe")
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s.hostname = s.Hostname
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if s.hostname == "" {
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s.hostname = prog
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}
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s.rootPath = s.Dir
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if s.Store != nil {
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_, isMemStore := s.Store.(*mem.Store)
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if isMemStore && !s.Ephemeral {
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return fmt.Errorf("in-memory store is only supported for Ephemeral nodes")
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}
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}
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logf := s.logf
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if s.rootPath == "" {
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confDir, err := os.UserConfigDir()
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if err != nil {
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return err
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}
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s.rootPath, err = getTSNetDir(logf, confDir, prog)
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if err != nil {
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return err
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}
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if err := os.MkdirAll(s.rootPath, 0700); err != nil {
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return err
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}
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}
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if fi, err := os.Stat(s.rootPath); err != nil {
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return err
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} else if !fi.IsDir() {
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return fmt.Errorf("%v is not a directory", s.rootPath)
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}
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cfgPath := filepath.Join(s.rootPath, "tailscaled.log.conf")
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lpc, err := logpolicy.ConfigFromFile(cfgPath)
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switch {
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case os.IsNotExist(err):
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lpc = logpolicy.NewConfig(logtail.CollectionNode)
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if err := lpc.Save(cfgPath); err != nil {
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return fmt.Errorf("logpolicy.Config.Save for %v: %w", cfgPath, err)
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}
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case err != nil:
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return fmt.Errorf("logpolicy.LoadConfig for %v: %w", cfgPath, err)
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}
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if err := lpc.Validate(logtail.CollectionNode); err != nil {
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return fmt.Errorf("logpolicy.Config.Validate for %v: %w", cfgPath, err)
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}
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logid := lpc.PublicID.String()
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s.logbuffer, err = filch.New(filepath.Join(s.rootPath, "tailscaled"), filch.Options{ReplaceStderr: false})
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if err != nil {
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return fmt.Errorf("error creating filch: %w", err)
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}
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closePool.add(s.logbuffer)
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c := logtail.Config{
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Collection: lpc.Collection,
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PrivateID: lpc.PrivateID,
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Stderr: ioutil.Discard, // log everything to Buffer
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Buffer: s.logbuffer,
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NewZstdEncoder: func() logtail.Encoder {
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w, err := smallzstd.NewEncoder(nil)
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if err != nil {
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panic(err)
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}
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return w
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},
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HTTPC: &http.Client{Transport: logpolicy.NewLogtailTransport(logtail.DefaultHost)},
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}
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s.logtail = logtail.NewLogger(c, logf)
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closePool.addFunc(func() { s.logtail.Shutdown(context.Background()) })
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s.linkMon, err = monitor.New(logf)
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if err != nil {
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return err
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}
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closePool.add(s.linkMon)
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s.dialer = new(tsdial.Dialer) // mutated below (before used)
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eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{
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ListenPort: 0,
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LinkMonitor: s.linkMon,
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Dialer: s.dialer,
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})
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if err != nil {
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return err
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}
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closePool.add(s.dialer)
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tunDev, magicConn, dns, ok := eng.(wgengine.InternalsGetter).GetInternals()
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if !ok {
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return fmt.Errorf("%T is not a wgengine.InternalsGetter", eng)
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}
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ns, err := netstack.Create(logf, tunDev, eng, magicConn, s.dialer, dns)
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if err != nil {
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return fmt.Errorf("netstack.Create: %w", err)
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}
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ns.ProcessLocalIPs = true
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ns.ForwardTCPIn = s.forwardTCP
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if err := ns.Start(); err != nil {
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return fmt.Errorf("failed to start netstack: %w", err)
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}
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s.dialer.UseNetstackForIP = func(ip netip.Addr) bool {
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_, ok := eng.PeerForIP(ip)
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return ok
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}
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s.dialer.NetstackDialTCP = func(ctx context.Context, dst netip.AddrPort) (net.Conn, error) {
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return ns.DialContextTCP(ctx, dst)
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}
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if s.Store == nil {
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stateFile := filepath.Join(s.rootPath, "tailscaled.state")
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logf("tsnet running state path %s", stateFile)
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s.Store, err = store.New(logf, stateFile)
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if err != nil {
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return err
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}
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}
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loginFlags := controlclient.LoginDefault
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if s.Ephemeral {
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loginFlags = controlclient.LoginEphemeral
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}
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lb, err := ipnlocal.NewLocalBackend(logf, logid, s.Store, s.dialer, eng, loginFlags)
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if err != nil {
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return fmt.Errorf("NewLocalBackend: %v", err)
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}
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lb.SetVarRoot(s.rootPath)
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logf("tsnet starting with hostname %q, varRoot %q", s.hostname, s.rootPath)
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s.lb = lb
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closePool.addFunc(func() { s.lb.Shutdown() })
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lb.SetDecompressor(func() (controlclient.Decompressor, error) {
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return smallzstd.NewDecoder(nil)
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})
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prefs := ipn.NewPrefs()
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prefs.Hostname = s.hostname
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prefs.WantRunning = true
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authKey := s.getAuthKey()
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err = lb.Start(ipn.Options{
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StateKey: ipn.GlobalDaemonStateKey,
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UpdatePrefs: prefs,
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AuthKey: authKey,
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})
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if err != nil {
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return fmt.Errorf("starting backend: %w", err)
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}
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st := lb.State()
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if st == ipn.NeedsLogin || envknob.Bool("TSNET_FORCE_LOGIN") {
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logf("LocalBackend state is %v; running StartLoginInteractive...", st)
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s.lb.StartLoginInteractive()
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} else if authKey != "" {
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logf("Authkey is set; but state is %v. Ignoring authkey. Re-run with TSNET_FORCE_LOGIN=1 to force use of authkey.", st)
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}
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go s.printAuthURLLoop()
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// Run the localapi handler, to allow fetching LetsEncrypt certs.
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lah := localapi.NewHandler(lb, logf, logid)
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lah.PermitWrite = true
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lah.PermitRead = true
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// Create an in-process listener.
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// nettest.Listen provides a in-memory pipe based implementation for net.Conn.
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// TODO(maisem): Rename nettest package to remove "test".
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lal := nettest.Listen("local-tailscaled.sock:80")
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s.localAPIListener = lal
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s.localClient = &tailscale.LocalClient{Dial: lal.Dial}
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go func() {
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if err := http.Serve(lal, lah); err != nil {
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logf("localapi serve error: %v", err)
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}
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}()
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closePool.add(s.localAPIListener)
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return nil
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}
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type closeOnErrorPool []func()
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func (p *closeOnErrorPool) add(c io.Closer) { *p = append(*p, func() { c.Close() }) }
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func (p *closeOnErrorPool) addFunc(fn func()) { *p = append(*p, fn) }
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func (p closeOnErrorPool) closeAllIfError(errp *error) {
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if *errp != nil {
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for _, closeFn := range p {
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closeFn()
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}
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}
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}
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func (s *Server) logf(format string, a ...interface{}) {
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if s.logtail != nil {
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s.logtail.Logf(format, a...)
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}
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if s.Logf != nil {
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s.Logf(format, a...)
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return
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}
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log.Printf(format, a...)
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}
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// printAuthURLLoop loops once every few seconds while the server is still running and
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// is in NeedsLogin state, printing out the auth URL.
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func (s *Server) printAuthURLLoop() {
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for {
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if s.shutdownCtx.Err() != nil {
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return
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}
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if st := s.lb.State(); st != ipn.NeedsLogin {
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s.logf("printAuthURLLoop: state is %v; stopping", st)
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return
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}
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st := s.lb.StatusWithoutPeers()
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if st.AuthURL != "" {
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s.logf("To start this tsnet server, restart with TS_AUTHKEY set, or go to: %s", st.AuthURL)
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}
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select {
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case <-time.After(5 * time.Second):
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case <-s.shutdownCtx.Done():
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return
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}
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}
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}
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func (s *Server) forwardTCP(c net.Conn, port uint16) {
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s.mu.Lock()
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ln, ok := s.listeners[listenKey{"tcp", "", fmt.Sprint(port)}]
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s.mu.Unlock()
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if !ok {
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c.Close()
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return
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}
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t := time.NewTimer(time.Second)
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defer t.Stop()
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select {
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case ln.conn <- c:
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case <-t.C:
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c.Close()
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}
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}
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// getTSNetDir usually just returns filepath.Join(confDir, "tsnet-"+prog)
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// with no error.
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//
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// One special case is that it renames old "tslib-" directories to
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// "tsnet-", and that rename might return an error.
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//
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// TODO(bradfitz): remove this maybe 6 months after 2022-03-17,
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// once people (notably Tailscale corp services) have updated.
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func getTSNetDir(logf logger.Logf, confDir, prog string) (string, error) {
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oldPath := filepath.Join(confDir, "tslib-"+prog)
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newPath := filepath.Join(confDir, "tsnet-"+prog)
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fi, err := os.Lstat(oldPath)
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if os.IsNotExist(err) {
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// Common path.
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return newPath, nil
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}
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if err != nil {
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return "", err
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}
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if !fi.IsDir() {
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return "", fmt.Errorf("expected old tslib path %q to be a directory; got %v", oldPath, fi.Mode())
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}
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// At this point, oldPath exists and is a directory. But does
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// the new path exist?
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fi, err = os.Lstat(newPath)
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if err == nil && fi.IsDir() {
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// New path already exists somehow. Ignore the old one and
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// don't try to migrate it.
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return newPath, nil
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}
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if err != nil && !os.IsNotExist(err) {
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return "", err
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}
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if err := os.Rename(oldPath, newPath); err != nil {
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return "", err
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}
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logf("renamed old tsnet state storage directory %q to %q", oldPath, newPath)
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return newPath, nil
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}
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// Listen announces only on the Tailscale network.
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// It will start the server if it has not been started yet.
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func (s *Server) Listen(network, addr string) (net.Listener, error) {
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host, port, err := net.SplitHostPort(addr)
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if err != nil {
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return nil, fmt.Errorf("tsnet: %w", err)
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}
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if err := s.Start(); err != nil {
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return nil, err
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}
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key := listenKey{network, host, port}
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ln := &listener{
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s: s,
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key: key,
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addr: addr,
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conn: make(chan net.Conn),
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}
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s.mu.Lock()
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if s.listeners == nil {
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s.listeners = map[listenKey]*listener{}
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}
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if _, ok := s.listeners[key]; ok {
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s.mu.Unlock()
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return nil, fmt.Errorf("tsnet: listener already open for %s, %s", network, addr)
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}
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s.listeners[key] = ln
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s.mu.Unlock()
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return ln, nil
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}
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type listenKey struct {
|
|
network string
|
|
host string
|
|
port string
|
|
}
|
|
|
|
type listener struct {
|
|
s *Server
|
|
key listenKey
|
|
addr string
|
|
conn chan net.Conn
|
|
}
|
|
|
|
func (ln *listener) Accept() (net.Conn, error) {
|
|
c, ok := <-ln.conn
|
|
if !ok {
|
|
return nil, fmt.Errorf("tsnet: %w", net.ErrClosed)
|
|
}
|
|
return c, nil
|
|
}
|
|
|
|
func (ln *listener) Addr() net.Addr { return addr{ln} }
|
|
func (ln *listener) Close() error {
|
|
ln.s.mu.Lock()
|
|
defer ln.s.mu.Unlock()
|
|
if v, ok := ln.s.listeners[ln.key]; ok && v == ln {
|
|
delete(ln.s.listeners, ln.key)
|
|
close(ln.conn)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
type addr struct{ ln *listener }
|
|
|
|
func (a addr) Network() string { return a.ln.key.network }
|
|
func (a addr) String() string { return a.ln.addr }
|