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349 lines
9.7 KiB
Go
349 lines
9.7 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package libtailscale
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import (
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"context"
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"errors"
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"fmt"
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"log"
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"net/http"
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"os"
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"path/filepath"
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"runtime/debug"
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"sync"
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"sync/atomic"
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"tailscale.com/drive/driveimpl"
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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/logtail"
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"tailscale.com/net/dns"
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"tailscale.com/net/netmon"
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"tailscale.com/net/netns"
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"tailscale.com/net/tsdial"
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"tailscale.com/paths"
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"tailscale.com/tsd"
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"tailscale.com/types/logger"
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"tailscale.com/types/logid"
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"tailscale.com/types/netmap"
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"tailscale.com/wgengine"
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"tailscale.com/wgengine/netstack"
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"tailscale.com/wgengine/router"
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)
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type App struct {
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dataDir string
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// enables direct file mode for the taildrop manager
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directFileRoot string
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// appCtx is a global reference to the com.tailscale.ipn.App instance.
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appCtx AppContext
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store *stateStore
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policyStore *syspolicyHandler
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logIDPublicAtomic atomic.Pointer[logid.PublicID]
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localAPIHandler http.Handler
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backend *ipnlocal.LocalBackend
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ready sync.WaitGroup
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}
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func start(dataDir, directFileRoot string, appCtx AppContext) Application {
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defer func() {
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if p := recover(); p != nil {
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log.Printf("panic in Start %s: %s", p, debug.Stack())
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panic(p)
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}
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}()
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initLogging(appCtx)
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// Set XDG_CACHE_HOME to make os.UserCacheDir work.
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if _, exists := os.LookupEnv("XDG_CACHE_HOME"); !exists {
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cachePath := filepath.Join(dataDir, "cache")
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os.Setenv("XDG_CACHE_HOME", cachePath)
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}
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// Set XDG_CONFIG_HOME to make os.UserConfigDir work.
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if _, exists := os.LookupEnv("XDG_CONFIG_HOME"); !exists {
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cfgPath := filepath.Join(dataDir, "config")
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os.Setenv("XDG_CONFIG_HOME", cfgPath)
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}
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// Set HOME to make os.UserHomeDir work.
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if _, exists := os.LookupEnv("HOME"); !exists {
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os.Setenv("HOME", dataDir)
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}
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return newApp(dataDir, directFileRoot, appCtx)
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}
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type backend struct {
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engine wgengine.Engine
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backend *ipnlocal.LocalBackend
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sys *tsd.System
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devices *multiTUN
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settings settingsFunc
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lastCfg *router.Config
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lastDNSCfg *dns.OSConfig
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netMon *netmon.Monitor
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logIDPublic logid.PublicID
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logger *logtail.Logger
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// avoidEmptyDNS controls whether to use fallback nameservers
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// when no nameservers are provided by Tailscale.
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avoidEmptyDNS bool
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appCtx AppContext
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}
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type settingsFunc func(*router.Config, *dns.OSConfig) error
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func (a *App) runBackend(ctx context.Context) error {
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paths.AppSharedDir.Store(a.dataDir)
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hostinfo.SetOSVersion(a.osVersion())
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hostinfo.SetPackage(a.appCtx.GetInstallSource())
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deviceModel := a.modelName()
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if a.isChromeOS() {
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deviceModel = "ChromeOS: " + deviceModel
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}
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hostinfo.SetDeviceModel(deviceModel)
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type configPair struct {
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rcfg *router.Config
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dcfg *dns.OSConfig
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}
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configs := make(chan configPair)
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configErrs := make(chan error)
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b, err := a.newBackend(a.dataDir, a.directFileRoot, a.appCtx, a.store, func(rcfg *router.Config, dcfg *dns.OSConfig) error {
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if rcfg == nil {
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return nil
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}
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configs <- configPair{rcfg, dcfg}
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return <-configErrs
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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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a.logIDPublicAtomic.Store(&b.logIDPublic)
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a.backend = b.backend
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defer b.CloseTUNs()
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h := localapi.NewHandler(b.backend, log.Printf, *a.logIDPublicAtomic.Load())
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h.PermitRead = true
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h.PermitWrite = true
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a.localAPIHandler = h
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a.ready.Done()
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// Contrary to the documentation for VpnService.Builder.addDnsServer,
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// ChromeOS doesn't fall back to the underlying network nameservers if
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// we don't provide any.
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b.avoidEmptyDNS = a.isChromeOS()
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var (
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cfg configPair
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state ipn.State
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networkMap *netmap.NetworkMap
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)
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stateCh := make(chan ipn.State)
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netmapCh := make(chan *netmap.NetworkMap)
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go b.backend.WatchNotifications(ctx, ipn.NotifyInitialNetMap|ipn.NotifyInitialPrefs|ipn.NotifyInitialState, func() {}, func(notify *ipn.Notify) bool {
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if notify.State != nil {
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stateCh <- *notify.State
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}
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if notify.NetMap != nil {
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netmapCh <- notify.NetMap
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}
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return true
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})
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for {
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select {
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case s := <-stateCh:
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state = s
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if cfg.rcfg != nil && state >= ipn.Starting && vpnService.service != nil {
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// On state change, check if there are router or config changes requiring an update to VPNBuilder
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if err := b.updateTUN(vpnService.service, cfg.rcfg, cfg.dcfg); err != nil {
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if errors.Is(err, errMultipleUsers) {
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// TODO: surface error to user
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}
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log.Printf("VPN update failed: %v", err)
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mp := new(ipn.MaskedPrefs)
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mp.WantRunning = false
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mp.WantRunningSet = true
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_, err := a.EditPrefs(*mp)
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if err != nil {
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log.Printf("localapi edit prefs error %v", err)
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}
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b.lastCfg = nil
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b.CloseTUNs()
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}
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}
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case n := <-netmapCh:
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networkMap = n
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case c := <-configs:
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cfg = c
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if b == nil || vpnService.service == nil || cfg.rcfg == nil {
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configErrs <- nil
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break
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}
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configErrs <- b.updateTUN(vpnService.service, cfg.rcfg, cfg.dcfg)
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case s := <-onVPNRequested:
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if vpnService.service != nil && vpnService.service.ID() == s.ID() {
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// Still the same VPN instance, do nothing
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break
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}
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netns.SetAndroidProtectFunc(func(fd int) error {
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if !s.Protect(int32(fd)) {
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// TODO(bradfitz): return an error back up to netns if this fails, once
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// we've had some experience with this and analyzed the logs over a wide
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// range of Android phones. For now we're being paranoid and conservative
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// and do the JNI call to protect best effort, only logging if it fails.
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// The risk of returning an error is that it breaks users on some Android
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// versions even when they're not using exit nodes. I'd rather the
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// relatively few number of exit node users file bug reports if Tailscale
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// doesn't work and then we can look for this log print.
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log.Printf("[unexpected] VpnService.protect(%d) returned false", fd)
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}
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return nil // even on error. see big TODO above.
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})
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log.Printf("onVPNRequested: rebind required")
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// TODO(catzkorn): When we start the android application
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// we bind sockets before we have access to the VpnService.protect()
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// function which is needed to avoid routing loops. When we activate
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// the service we get access to the protect, but do not retrospectively
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// protect the sockets already opened, which breaks connectivity.
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// As a temporary fix, we rebind and protect the magicsock.Conn on connect
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// which restores connectivity.
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// See https://github.com/tailscale/corp/issues/13814
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b.backend.DebugRebind()
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vpnService.service = s
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if networkMap != nil {
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// TODO
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}
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if cfg.rcfg != nil && state >= ipn.Starting {
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if err := b.updateTUN(vpnService.service, cfg.rcfg, cfg.dcfg); err != nil {
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log.Printf("VPN update failed: %v", err)
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vpnService.service.Close()
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b.lastCfg = nil
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b.CloseTUNs()
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}
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}
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case s := <-onDisconnect:
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b.CloseTUNs()
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if vpnService.service != nil && vpnService.service.ID() == s.ID() {
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netns.SetAndroidProtectFunc(nil)
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vpnService.service = nil
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}
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case i := <-onDNSConfigChanged:
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if b != nil {
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go b.NetworkChanged(i)
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}
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}
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}
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}
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func (a *App) newBackend(dataDir, directFileRoot string, appCtx AppContext, store *stateStore,
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settings settingsFunc) (*backend, error) {
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sys := new(tsd.System)
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sys.Set(store)
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logf := logger.RusagePrefixLog(log.Printf)
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b := &backend{
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devices: newTUNDevices(),
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settings: settings,
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appCtx: appCtx,
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}
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var logID logid.PrivateID
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logID.UnmarshalText([]byte("dead0000dead0000dead0000dead0000dead0000dead0000dead0000dead0000"))
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storedLogID, err := store.read(logPrefKey)
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// In all failure cases we ignore any errors and continue with the dead value above.
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if err != nil || storedLogID == nil {
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// Read failed or there was no previous log id.
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newLogID, err := logid.NewPrivateID()
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if err == nil {
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logID = newLogID
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enc, err := newLogID.MarshalText()
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if err == nil {
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store.write(logPrefKey, enc)
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}
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}
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} else {
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logID.UnmarshalText([]byte(storedLogID))
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}
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netMon, err := netmon.New(logf)
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if err != nil {
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log.Printf("netmon.New: %w", err)
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}
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b.netMon = netMon
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b.setupLogs(dataDir, logID, logf, sys.HealthTracker())
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dialer := new(tsdial.Dialer)
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vf := &VPNFacade{
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SetBoth: b.setCfg,
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GetBaseConfigFunc: b.getDNSBaseConfig,
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}
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engine, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{
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Tun: b.devices,
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Router: vf,
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DNS: vf,
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ReconfigureVPN: vf.ReconfigureVPN,
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Dialer: dialer,
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SetSubsystem: sys.Set,
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NetMon: b.netMon,
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HealthTracker: sys.HealthTracker(),
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DriveForLocal: driveimpl.NewFileSystemForLocal(logf),
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})
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if err != nil {
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return nil, fmt.Errorf("runBackend: NewUserspaceEngine: %v", err)
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}
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sys.Set(engine)
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b.logIDPublic = logID.Public()
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ns, err := netstack.Create(logf, sys.Tun.Get(), engine, sys.MagicSock.Get(), dialer, sys.DNSManager.Get(), sys.ProxyMapper(), nil)
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if err != nil {
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return nil, fmt.Errorf("netstack.Create: %w", err)
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}
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sys.Set(ns)
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ns.ProcessLocalIPs = false // let Android kernel handle it; VpnBuilder sets this up
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ns.ProcessSubnets = true // for Android-being-an-exit-node support
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sys.NetstackRouter.Set(true)
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if w, ok := sys.Tun.GetOK(); ok {
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w.Start()
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}
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lb, err := ipnlocal.NewLocalBackend(logf, logID.Public(), sys, 0)
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if err != nil {
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engine.Close()
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return nil, fmt.Errorf("runBackend: NewLocalBackend: %v", err)
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}
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lb.SetDirectFileRoot(directFileRoot)
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if err := ns.Start(lb); err != nil {
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return nil, fmt.Errorf("startNetstack: %w", err)
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}
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if b.logger != nil {
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lb.SetLogFlusher(b.logger.StartFlush)
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}
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b.engine = engine
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b.backend = lb
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b.sys = sys
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go func() {
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err := lb.Start(ipn.Options{})
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if err != nil {
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log.Printf("Failed to start LocalBackend, panicking: %s", err)
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panic(err)
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}
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a.ready.Done()
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}()
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return b, nil
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}
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