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tailscale/ipn/ipnlocal/local.go

3175 lines
89 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.
package ipnlocal
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"net"
"net/http"
"os"
"os/exec"
"os/user"
"path/filepath"
"runtime"
"sort"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"inet.af/netaddr"
"tailscale.com/client/tailscale/apitype"
"tailscale.com/control/controlclient"
"tailscale.com/health"
"tailscale.com/hostinfo"
"tailscale.com/ipn"
"tailscale.com/ipn/ipnstate"
"tailscale.com/ipn/policy"
"tailscale.com/net/dns"
"tailscale.com/net/interfaces"
"tailscale.com/net/tsaddr"
"tailscale.com/net/tsdial"
"tailscale.com/paths"
"tailscale.com/portlist"
"tailscale.com/tailcfg"
"tailscale.com/types/dnstype"
"tailscale.com/types/empty"
"tailscale.com/types/key"
"tailscale.com/types/logger"
"tailscale.com/types/netmap"
"tailscale.com/types/persist"
"tailscale.com/types/preftype"
"tailscale.com/util/deephash"
"tailscale.com/util/dnsname"
"tailscale.com/util/multierr"
"tailscale.com/util/osshare"
"tailscale.com/util/systemd"
"tailscale.com/version"
"tailscale.com/version/distro"
"tailscale.com/wgengine"
"tailscale.com/wgengine/filter"
"tailscale.com/wgengine/magicsock"
"tailscale.com/wgengine/router"
"tailscale.com/wgengine/wgcfg"
"tailscale.com/wgengine/wgcfg/nmcfg"
)
var controlDebugFlags = getControlDebugFlags()
func getControlDebugFlags() []string {
if e := os.Getenv("TS_DEBUG_CONTROL_FLAGS"); e != "" {
return strings.Split(e, ",")
}
return nil
}
// LocalBackend is the glue between the major pieces of the Tailscale
// network software: the cloud control plane (via controlclient), the
// network data plane (via wgengine), and the user-facing UIs and CLIs
// (collectively called "frontends", via LocalBackend's implementation
// of the Backend interface).
//
// LocalBackend implements the overall state machine for the Tailscale
// application. Frontends, controlclient and wgengine can feed events
// into LocalBackend to advance the state machine, and advancing the
// state machine generates events back out to zero or more components.
type LocalBackend struct {
// Elements that are thread-safe or constant after construction.
ctx context.Context // canceled by Close
ctxCancel context.CancelFunc // cancels ctx
logf logger.Logf // general logging
keyLogf logger.Logf // for printing list of peers on change
statsLogf logger.Logf // for printing peers stats on change
e wgengine.Engine
store ipn.StateStore
dialer *tsdial.Dialer // non-nil
backendLogID string
unregisterLinkMon func()
unregisterHealthWatch func()
portpoll *portlist.Poller // may be nil
portpollOnce sync.Once // guards starting readPoller
gotPortPollRes chan struct{} // closed upon first readPoller result
serverURL string // tailcontrol URL
newDecompressor func() (controlclient.Decompressor, error)
varRoot string // or empty if SetVarRoot never called
filterHash deephash.Sum
filterAtomic atomic.Value // of *filter.Filter
// The mutex protects the following elements.
mu sync.Mutex
httpTestClient *http.Client // for controlclient. nil by default, used by tests.
ccGen clientGen // function for producing controlclient; lazily populated
notify func(ipn.Notify)
cc controlclient.Client
stateKey ipn.StateKey // computed in part from user-provided value
userID string // current controlling user ID (for Windows, primarily)
prefs *ipn.Prefs
inServerMode bool
machinePrivKey key.MachinePrivate
state ipn.State
capFileSharing bool // whether netMap contains the file sharing capability
// hostinfo is mutated in-place while mu is held.
hostinfo *tailcfg.Hostinfo
// netMap is not mutated in-place once set.
netMap *netmap.NetworkMap
nodeByAddr map[netaddr.IP]*tailcfg.Node
activeLogin string // last logged LoginName from netMap
engineStatus ipn.EngineStatus
endpoints []tailcfg.Endpoint
blocked bool
keyExpired bool
authURL string // cleared on Notify
authURLSticky string // not cleared on Notify
interact bool
prevIfState *interfaces.State
peerAPIServer *peerAPIServer // or nil
peerAPIListeners []*peerAPIListener
incomingFiles map[*incomingFile]bool
// directFileRoot, if non-empty, means to write received files
// directly to this directory, without staging them in an
// intermediate buffered directory for "pick-up" later. If
// empty, the files are received in a daemon-owned location
// and the localapi is used to enumerate, download, and delete
// them. This is used on macOS where the GUI lifetime is the
// same as the Network Extension lifetime and we can thus avoid
// double-copying files by writing them to the right location
// immediately.
// It's also used on Synology & TrueNAS, but in that case DoFinalRename
// is also set true, which moves the *.partial file to its final
// name on completion.
directFileRoot string
directFileDoFinalRename bool // false on macOS, true on Synology & TrueNAS
// statusLock must be held before calling statusChanged.Wait() or
// statusChanged.Broadcast().
statusLock sync.Mutex
statusChanged *sync.Cond
}
// clientGen is a func that creates a control plane client.
// It's the type used by LocalBackend.SetControlClientGetterForTesting.
type clientGen func(controlclient.Options) (controlclient.Client, error)
// NewLocalBackend returns a new LocalBackend that is ready to run,
// but is not actually running.
//
// If dialer is nil, a new one is made.
func NewLocalBackend(logf logger.Logf, logid string, store ipn.StateStore, dialer *tsdial.Dialer, e wgengine.Engine) (*LocalBackend, error) {
if e == nil {
panic("ipn.NewLocalBackend: engine must not be nil")
}
if dialer == nil {
dialer = new(tsdial.Dialer)
}
osshare.SetFileSharingEnabled(false, logf)
ctx, cancel := context.WithCancel(context.Background())
portpoll, err := portlist.NewPoller()
if err != nil {
logf("skipping portlist: %s", err)
}
b := &LocalBackend{
ctx: ctx,
ctxCancel: cancel,
logf: logf,
keyLogf: logger.LogOnChange(logf, 5*time.Minute, time.Now),
statsLogf: logger.LogOnChange(logf, 5*time.Minute, time.Now),
e: e,
store: store,
dialer: dialer,
backendLogID: logid,
state: ipn.NoState,
portpoll: portpoll,
gotPortPollRes: make(chan struct{}),
}
// Default filter blocks everything and logs nothing, until Start() is called.
b.setFilter(filter.NewAllowNone(logf, &netaddr.IPSet{}))
b.statusChanged = sync.NewCond(&b.statusLock)
b.e.SetStatusCallback(b.setWgengineStatus)
linkMon := e.GetLinkMonitor()
b.prevIfState = linkMon.InterfaceState()
// Call our linkChange code once with the current state, and
// then also whenever it changes:
b.linkChange(false, linkMon.InterfaceState())
b.unregisterLinkMon = linkMon.RegisterChangeCallback(b.linkChange)
b.unregisterHealthWatch = health.RegisterWatcher(b.onHealthChange)
wiredPeerAPIPort := false
if ig, ok := e.(wgengine.InternalsGetter); ok {
if tunWrap, _, ok := ig.GetInternals(); ok {
tunWrap.PeerAPIPort = b.getPeerAPIPortForTSMPPing
wiredPeerAPIPort = true
}
}
if !wiredPeerAPIPort {
b.logf("[unexpected] failed to wire up peer API port for engine %T", e)
}
return b, nil
}
// Dialer returns the backend's dialer.
func (b *LocalBackend) Dialer() *tsdial.Dialer {
return b.dialer
}
// SetDirectFileRoot sets the directory to download files to directly,
// without buffering them through an intermediate daemon-owned
// tailcfg.UserID-specific directory.
//
// This must be called before the LocalBackend starts being used.
func (b *LocalBackend) SetDirectFileRoot(dir string) {
b.mu.Lock()
defer b.mu.Unlock()
b.directFileRoot = dir
}
// SetDirectFileDoFinalRename sets whether the peerapi file server should rename
// a received "name.partial" file to "name" when the download is complete.
//
// This only applies when SetDirectFileRoot is non-empty.
// The default is false.
func (b *LocalBackend) SetDirectFileDoFinalRename(v bool) {
b.mu.Lock()
defer b.mu.Unlock()
b.directFileDoFinalRename = v
}
// b.mu must be held.
func (b *LocalBackend) maybePauseControlClientLocked() {
if b.cc == nil {
return
}
networkUp := b.prevIfState.AnyInterfaceUp()
b.cc.SetPaused((b.state == ipn.Stopped && b.netMap != nil) || !networkUp)
}
// linkChange is our link monitor callback, called whenever the network changes.
// major is whether ifst is different than earlier.
func (b *LocalBackend) linkChange(major bool, ifst *interfaces.State) {
b.mu.Lock()
defer b.mu.Unlock()
hadPAC := b.prevIfState.HasPAC()
b.prevIfState = ifst
b.maybePauseControlClientLocked()
// If the PAC-ness of the network changed, reconfig wireguard+route to
// add/remove subnets.
if hadPAC != ifst.HasPAC() {
b.logf("linkChange: in state %v; PAC changed from %v->%v", b.state, hadPAC, ifst.HasPAC())
switch b.state {
case ipn.NoState, ipn.Stopped:
// Do nothing.
default:
go b.authReconfig()
}
}
// If the local network configuration has changed, our filter may
// need updating to tweak default routes.
b.updateFilter(b.netMap, b.prefs)
if peerAPIListenAsync && b.netMap != nil && b.state == ipn.Running {
want := len(b.netMap.Addresses)
if len(b.peerAPIListeners) < want {
b.logf("linkChange: peerAPIListeners too low; trying again")
go b.initPeerAPIListener()
}
}
}
func (b *LocalBackend) onHealthChange(sys health.Subsystem, err error) {
if err == nil {
b.logf("health(%q): ok", sys)
} else {
b.logf("health(%q): error: %v", sys, err)
}
}
// Shutdown halts the backend and all its sub-components. The backend
// can no longer be used after Shutdown returns.
func (b *LocalBackend) Shutdown() {
b.mu.Lock()
cc := b.cc
b.mu.Unlock()
b.unregisterLinkMon()
b.unregisterHealthWatch()
if cc != nil {
cc.Shutdown()
}
b.ctxCancel()
b.e.Close()
b.e.Wait()
}
// Prefs returns a copy of b's current prefs, with any private keys removed.
func (b *LocalBackend) Prefs() *ipn.Prefs {
b.mu.Lock()
defer b.mu.Unlock()
p := b.prefs.Clone()
if p != nil && p.Persist != nil {
p.Persist.LegacyFrontendPrivateMachineKey = key.MachinePrivate{}
p.Persist.PrivateNodeKey = key.NodePrivate{}
p.Persist.OldPrivateNodeKey = key.NodePrivate{}
}
return p
}
// Status returns the latest status of the backend and its
// sub-components.
func (b *LocalBackend) Status() *ipnstate.Status {
sb := new(ipnstate.StatusBuilder)
b.UpdateStatus(sb)
return sb.Status()
}
// StatusWithoutPeers is like Status but omits any details
// of peers.
func (b *LocalBackend) StatusWithoutPeers() *ipnstate.Status {
sb := new(ipnstate.StatusBuilder)
b.updateStatus(sb, nil)
return sb.Status()
}
// UpdateStatus implements ipnstate.StatusUpdater.
func (b *LocalBackend) UpdateStatus(sb *ipnstate.StatusBuilder) {
b.e.UpdateStatus(sb)
b.updateStatus(sb, b.populatePeerStatusLocked)
}
// updateStatus populates sb with status.
//
// extraLocked, if non-nil, is called while b.mu is still held.
func (b *LocalBackend) updateStatus(sb *ipnstate.StatusBuilder, extraLocked func(*ipnstate.StatusBuilder)) {
b.mu.Lock()
defer b.mu.Unlock()
sb.MutateStatus(func(s *ipnstate.Status) {
s.Version = version.Long
s.BackendState = b.state.String()
s.AuthURL = b.authURLSticky
if err := health.OverallError(); err != nil {
switch e := err.(type) {
case multierr.Error:
for _, err := range e.Errors() {
s.Health = append(s.Health, err.Error())
}
default:
s.Health = append(s.Health, err.Error())
}
}
if b.netMap != nil {
s.MagicDNSSuffix = b.netMap.MagicDNSSuffix()
s.CertDomains = append([]string(nil), b.netMap.DNS.CertDomains...)
}
})
sb.MutateSelfStatus(func(ss *ipnstate.PeerStatus) {
ss.Online = health.GetInPollNetMap()
if b.netMap != nil {
ss.HostName = b.netMap.Hostinfo.Hostname
ss.DNSName = b.netMap.Name
ss.UserID = b.netMap.User
if sn := b.netMap.SelfNode; sn != nil {
ss.ID = sn.StableID
if c := sn.Capabilities; len(c) > 0 {
ss.Capabilities = append([]string(nil), c...)
}
}
} else {
ss.HostName, _ = os.Hostname()
}
for _, pln := range b.peerAPIListeners {
ss.PeerAPIURL = append(ss.PeerAPIURL, pln.urlStr)
}
})
// TODO: hostinfo, and its networkinfo
// TODO: EngineStatus copy (and deprecate it?)
if extraLocked != nil {
extraLocked(sb)
}
}
func (b *LocalBackend) populatePeerStatusLocked(sb *ipnstate.StatusBuilder) {
if b.netMap == nil {
return
}
for id, up := range b.netMap.UserProfiles {
sb.AddUser(id, up)
}
for _, p := range b.netMap.Peers {
var lastSeen time.Time
if p.LastSeen != nil {
lastSeen = *p.LastSeen
}
var tailscaleIPs = make([]netaddr.IP, 0, len(p.Addresses))
for _, addr := range p.Addresses {
if addr.IsSingleIP() && tsaddr.IsTailscaleIP(addr.IP()) {
tailscaleIPs = append(tailscaleIPs, addr.IP())
}
}
exitNodeOption := tsaddr.PrefixesContainsFunc(p.AllowedIPs, func(r netaddr.IPPrefix) bool {
return r.Bits() == 0
})
sb.AddPeer(p.Key, &ipnstate.PeerStatus{
InNetworkMap: true,
ID: p.StableID,
UserID: p.User,
TailscaleIPs: tailscaleIPs,
HostName: p.Hostinfo.Hostname,
DNSName: p.Name,
OS: p.Hostinfo.OS,
KeepAlive: p.KeepAlive,
Created: p.Created,
LastSeen: lastSeen,
Online: p.Online != nil && *p.Online,
ShareeNode: p.Hostinfo.ShareeNode,
ExitNode: p.StableID != "" && p.StableID == b.prefs.ExitNodeID,
ExitNodeOption: exitNodeOption,
})
}
}
// WhoIs reports the node and user who owns the node with the given IP:port.
// If the IP address is a Tailscale IP, the provided port may be 0.
// If ok == true, n and u are valid.
func (b *LocalBackend) WhoIs(ipp netaddr.IPPort) (n *tailcfg.Node, u tailcfg.UserProfile, ok bool) {
b.mu.Lock()
defer b.mu.Unlock()
n, ok = b.nodeByAddr[ipp.IP()]
if !ok {
var ip netaddr.IP
if ipp.Port() != 0 {
ip, ok = b.e.WhoIsIPPort(ipp)
}
if !ok {
return nil, u, false
}
n, ok = b.nodeByAddr[ip]
if !ok {
return nil, u, false
}
}
u, ok = b.netMap.UserProfiles[n.User]
if !ok {
return nil, u, false
}
return n, u, true
}
// SetDecompressor sets a decompression function, which must be a zstd
// reader.
//
// This exists because the iOS/Mac NetworkExtension is very resource
// constrained, and the zstd package is too heavy to fit in the
// constrained RSS limit.
func (b *LocalBackend) SetDecompressor(fn func() (controlclient.Decompressor, error)) {
b.newDecompressor = fn
}
// setClientStatus is the callback invoked by the control client whenever it posts a new status.
// Among other things, this is where we update the netmap, packet filters, DNS and DERP maps.
func (b *LocalBackend) setClientStatus(st controlclient.Status) {
// The following do not depend on any data for which we need to lock b.
if st.Err != nil {
// TODO(crawshaw): display in the UI.
if errors.Is(st.Err, io.EOF) {
b.logf("[v1] Received error: EOF")
return
}
b.logf("Received error: %v", st.Err)
var uerr controlclient.UserVisibleError
if errors.As(st.Err, &uerr) {
s := uerr.UserVisibleError()
b.send(ipn.Notify{ErrMessage: &s})
}
return
}
b.mu.Lock()
wasBlocked := b.blocked
keyExpiryExtended := false
if st.NetMap != nil {
wasExpired := b.keyExpired
isExpired := !st.NetMap.Expiry.IsZero() && st.NetMap.Expiry.Before(time.Now())
if wasExpired && !isExpired {
keyExpiryExtended = true
}
b.keyExpired = isExpired
}
b.mu.Unlock()
if keyExpiryExtended && wasBlocked {
// Key extended, unblock the engine
b.blockEngineUpdates(false)
}
if st.LoginFinished != nil && wasBlocked {
// Auth completed, unblock the engine
b.blockEngineUpdates(false)
b.authReconfig()
b.send(ipn.Notify{LoginFinished: &empty.Message{}})
}
prefsChanged := false
// Lock b once and do only the things that require locking.
b.mu.Lock()
if st.LogoutFinished != nil {
// Since we're logged out now, our netmap cache is invalid.
// Since st.NetMap==nil means "netmap is unchanged", there is
// no other way to represent this change.
b.setNetMapLocked(nil)
b.e.SetNetworkMap(new(netmap.NetworkMap))
}
prefs := b.prefs
stateKey := b.stateKey
netMap := b.netMap
interact := b.interact
if prefs.ControlURL == "" {
// Once we get a message from the control plane, set
// our ControlURL pref explicitly. This causes a
// future "tailscale up" to start checking for
// implicit setting reverts, which it doesn't do when
// ControlURL is blank.
prefs.ControlURL = prefs.ControlURLOrDefault()
prefsChanged = true
}
if st.Persist != nil {
if !b.prefs.Persist.Equals(st.Persist) {
prefsChanged = true
b.prefs.Persist = st.Persist.Clone()
}
}
if st.NetMap != nil {
if b.findExitNodeIDLocked(st.NetMap) {
prefsChanged = true
}
b.setNetMapLocked(st.NetMap)
}
if st.URL != "" {
b.authURL = st.URL
b.authURLSticky = st.URL
}
if wasBlocked && st.LoginFinished != nil {
// Interactive login finished successfully (URL visited).
// After an interactive login, the user always wants
// WantRunning.
if !b.prefs.WantRunning || b.prefs.LoggedOut {
prefsChanged = true
}
b.prefs.WantRunning = true
b.prefs.LoggedOut = false
}
// Prefs will be written out; this is not safe unless locked or cloned.
if prefsChanged {
prefs = b.prefs.Clone()
}
b.mu.Unlock()
// Now complete the lock-free parts of what we started while locked.
if prefsChanged {
if stateKey != "" {
if err := b.store.WriteState(stateKey, prefs.ToBytes()); err != nil {
b.logf("Failed to save new controlclient state: %v", err)
}
}
b.send(ipn.Notify{Prefs: prefs})
}
if st.NetMap != nil {
if netMap != nil {
diff := st.NetMap.ConciseDiffFrom(netMap)
if strings.TrimSpace(diff) == "" {
b.logf("[v1] netmap diff: (none)")
} else {
b.logf("netmap diff:\n%v", diff)
}
}
b.updateFilter(st.NetMap, prefs)
b.e.SetNetworkMap(st.NetMap)
b.e.SetDERPMap(st.NetMap.DERPMap)
b.send(ipn.Notify{NetMap: st.NetMap})
}
if st.URL != "" {
b.logf("Received auth URL: %.20v...", st.URL)
if interact {
b.popBrowserAuthNow()
}
}
b.stateMachine()
// This is currently (2020-07-28) necessary; conditionally disabling it is fragile!
// This is where netmap information gets propagated to router and magicsock.
b.authReconfig()
}
// findExitNodeIDLocked updates b.prefs to reference an exit node by ID,
// rather than by IP. It returns whether prefs was mutated.
func (b *LocalBackend) findExitNodeIDLocked(nm *netmap.NetworkMap) (prefsChanged bool) {
if nm == nil {
// No netmap, can't resolve anything.
return false
}
// If we have a desired IP on file, try to find the corresponding
// node.
if b.prefs.ExitNodeIP.IsZero() {
return false
}
// IP takes precedence over ID, so if both are set, clear ID.
if b.prefs.ExitNodeID != "" {
b.prefs.ExitNodeID = ""
prefsChanged = true
}
for _, peer := range nm.Peers {
for _, addr := range peer.Addresses {
if !addr.IsSingleIP() || addr.IP() != b.prefs.ExitNodeIP {
continue
}
// Found the node being referenced, upgrade prefs to
// reference it directly for next time.
b.prefs.ExitNodeID = peer.StableID
b.prefs.ExitNodeIP = netaddr.IP{}
return true
}
}
return false
}
// setWgengineStatus is the callback by the wireguard engine whenever it posts a new status.
// This updates the endpoints both in the backend and in the control client.
func (b *LocalBackend) setWgengineStatus(s *wgengine.Status, err error) {
if err != nil {
b.logf("wgengine status error: %v", err)
b.broadcastStatusChanged()
return
}
if s == nil {
b.logf("[unexpected] non-error wgengine update with status=nil: %v", s)
b.broadcastStatusChanged()
return
}
b.mu.Lock()
es := b.parseWgStatusLocked(s)
cc := b.cc
b.engineStatus = es
needUpdateEndpoints := !endpointsEqual(s.LocalAddrs, b.endpoints)
if needUpdateEndpoints {
b.endpoints = append([]tailcfg.Endpoint{}, s.LocalAddrs...)
}
b.mu.Unlock()
if cc != nil {
if needUpdateEndpoints {
cc.UpdateEndpoints(0, s.LocalAddrs)
}
b.stateMachine()
}
b.broadcastStatusChanged()
b.send(ipn.Notify{Engine: &es})
}
func (b *LocalBackend) broadcastStatusChanged() {
// The sync.Cond docs say: "It is allowed but not required for the caller to hold c.L during the call."
// In this particular case, we must acquire b.statusLock. Otherwise we might broadcast before
// the waiter (in requestEngineStatusAndWait) starts to wait, in which case
// the waiter can get stuck indefinitely. See PR 2865.
b.statusLock.Lock()
b.statusChanged.Broadcast()
b.statusLock.Unlock()
}
func endpointsEqual(x, y []tailcfg.Endpoint) bool {
if len(x) != len(y) {
return false
}
for i := range x {
if x[i] != y[i] {
return false
}
}
return true
}
func (b *LocalBackend) SetNotifyCallback(notify func(ipn.Notify)) {
b.mu.Lock()
defer b.mu.Unlock()
b.notify = notify
}
// SetHTTPTestClient sets an alternate HTTP client to use with
// connections to the coordination server. It exists for
// testing. Using nil means to use the default.
func (b *LocalBackend) SetHTTPTestClient(c *http.Client) {
b.mu.Lock()
defer b.mu.Unlock()
b.httpTestClient = c
}
// SetControlClientGetterForTesting sets the func that creates a
// control plane client. It can be called at most once, before Start.
func (b *LocalBackend) SetControlClientGetterForTesting(newControlClient func(controlclient.Options) (controlclient.Client, error)) {
b.mu.Lock()
defer b.mu.Unlock()
if b.ccGen != nil {
panic("invalid use of SetControlClientGetterForTesting after Start")
}
b.ccGen = newControlClient
}
func (b *LocalBackend) getNewControlClientFunc() clientGen {
b.mu.Lock()
defer b.mu.Unlock()
if b.ccGen == nil {
// Initialize it rather than just returning the
// default to make any future call to
// SetControlClientGetterForTesting panic.
b.ccGen = func(opts controlclient.Options) (controlclient.Client, error) {
return controlclient.New(opts)
}
}
return b.ccGen
}
// startIsNoopLocked reports whether a Start call on this LocalBackend
// with the provided Start Options would be a useless no-op.
//
// TODO(apenwarr): we shouldn't need this.
// The state machine is now nearly clean enough where it can accept a new
// connection while in any state, not just Running, and on any platform.
// We'd want to add a few more tests to state_test.go to ensure this continues
// to work as expected.
//
// b.mu must be held.
func (b *LocalBackend) startIsNoopLocked(opts ipn.Options) bool {
// Options has 5 fields; check all of them:
// * FrontendLogID
// * StateKey
// * Prefs
// * UpdatePrefs
// * AuthKey
return b.state == ipn.Running &&
b.hostinfo != nil &&
b.hostinfo.FrontendLogID == opts.FrontendLogID &&
b.stateKey == opts.StateKey &&
opts.Prefs == nil &&
opts.UpdatePrefs == nil &&
opts.AuthKey == ""
}
// Start applies the configuration specified in opts, and starts the
// state machine.
//
// TODO(danderson): this function is trying to do too many things at
// once: it loads state, or imports it, or updates prefs sometimes,
// contains some settings that are one-shot things done by `tailscale
// up` because we had nowhere else to put them, and there's no clear
// guarantee that switching from one user's state to another is
// actually a supported operation (it should be, but it's very unclear
// from the following whether or not that is a safe transition).
func (b *LocalBackend) Start(opts ipn.Options) error {
if opts.Prefs == nil && opts.StateKey == "" {
return errors.New("no state key or prefs provided")
}
if opts.Prefs != nil {
b.logf("Start: %v", opts.Prefs.Pretty())
} else {
b.logf("Start")
}
b.mu.Lock()
// The iOS client sends a "Start" whenever its UI screen comes
// up, just because it wants a netmap. That should be fixed,
// but meanwhile we can make Start cheaper here for such a
// case and not restart the world (which takes a few seconds).
// Instead, just send a notify with the state that iOS needs.
if b.startIsNoopLocked(opts) {
b.logf("Start: already running; sending notify")
nm := b.netMap
state := b.state
b.mu.Unlock()
b.send(ipn.Notify{
State: &state,
NetMap: nm,
Prefs: b.prefs,
LoginFinished: new(empty.Message),
})
return nil
}
hostinfo := hostinfo.New()
hostinfo.BackendLogID = b.backendLogID
hostinfo.FrontendLogID = opts.FrontendLogID
if b.cc != nil {
// TODO(apenwarr): avoid the need to reinit controlclient.
// This will trigger a full relogin/reconfigure cycle every
// time a Handle reconnects to the backend. Ideally, we
// would send the new Prefs and everything would get back
// into sync with the minimal changes. But that's not how it
// is right now, which is a sign that the code is still too
// complicated.
b.mu.Unlock()
b.cc.Shutdown()
b.mu.Lock()
}
httpTestClient := b.httpTestClient
if b.hostinfo != nil {
hostinfo.Services = b.hostinfo.Services // keep any previous session and netinfo
hostinfo.NetInfo = b.hostinfo.NetInfo
}
b.hostinfo = hostinfo
b.state = ipn.NoState
if err := b.loadStateLocked(opts.StateKey, opts.Prefs); err != nil {
b.mu.Unlock()
return fmt.Errorf("loading requested state: %v", err)
}
if opts.UpdatePrefs != nil {
newPrefs := opts.UpdatePrefs
newPrefs.Persist = b.prefs.Persist
b.prefs = newPrefs
if opts.StateKey != "" {
if err := b.store.WriteState(opts.StateKey, b.prefs.ToBytes()); err != nil {
b.logf("failed to save UpdatePrefs state: %v", err)
}
}
}
wantRunning := b.prefs.WantRunning
if wantRunning {
if err := b.initMachineKeyLocked(); err != nil {
return fmt.Errorf("initMachineKeyLocked: %w", err)
}
}
loggedOut := b.prefs.LoggedOut
b.inServerMode = b.prefs.ForceDaemon
b.serverURL = b.prefs.ControlURLOrDefault()
if b.inServerMode || runtime.GOOS == "windows" {
b.logf("Start: serverMode=%v", b.inServerMode)
}
applyPrefsToHostinfo(hostinfo, b.prefs)
b.setNetMapLocked(nil)
persistv := b.prefs.Persist
b.mu.Unlock()
b.updateFilter(nil, nil)
if b.portpoll != nil {
b.portpollOnce.Do(func() {
go b.portpoll.Run(b.ctx)
go b.readPoller()
// Give the poller a second to get results to
// prevent it from restarting our map poll
// HTTP request (via doSetHostinfoFilterServices >
// cli.SetHostinfo). In practice this is very quick.
t0 := time.Now()
timer := time.NewTimer(time.Second)
select {
case <-b.gotPortPollRes:
b.logf("got initial portlist info in %v", time.Since(t0).Round(time.Millisecond))
timer.Stop()
case <-timer.C:
b.logf("timeout waiting for initial portlist")
}
})
}
var discoPublic key.DiscoPublic
if controlclient.Debug.Disco {
discoPublic = b.e.DiscoPublicKey()
}
var err error
if persistv == nil {
// let controlclient initialize it
persistv = &persist.Persist{}
}
isNetstack := wgengine.IsNetstackRouter(b.e)
debugFlags := controlDebugFlags
if isNetstack {
debugFlags = append([]string{"netstack"}, debugFlags...)
}
// TODO(apenwarr): The only way to change the ServerURL is to
// re-run b.Start(), because this is the only place we create a
// new controlclient. SetPrefs() allows you to overwrite ServerURL,
// but it won't take effect until the next Start().
cc, err := b.getNewControlClientFunc()(controlclient.Options{
GetMachinePrivateKey: b.createGetMachinePrivateKeyFunc(),
Logf: logger.WithPrefix(b.logf, "control: "),
Persist: *persistv,
ServerURL: b.serverURL,
AuthKey: opts.AuthKey,
Hostinfo: hostinfo,
KeepAlive: true,
NewDecompressor: b.newDecompressor,
HTTPTestClient: httpTestClient,
DiscoPublicKey: discoPublic,
DebugFlags: debugFlags,
LinkMonitor: b.e.GetLinkMonitor(),
Pinger: b.e,
// Don't warn about broken Linux IP forwarding when
// netstack is being used.
SkipIPForwardingCheck: isNetstack,
})
if err != nil {
return err
}
b.mu.Lock()
b.cc = cc
endpoints := b.endpoints
b.mu.Unlock()
if endpoints != nil {
cc.UpdateEndpoints(0, endpoints)
}
cc.SetStatusFunc(b.setClientStatus)
b.e.SetNetInfoCallback(b.setNetInfo)
b.mu.Lock()
prefs := b.prefs.Clone()
b.mu.Unlock()
blid := b.backendLogID
b.logf("Backend: logs: be:%v fe:%v", blid, opts.FrontendLogID)
b.send(ipn.Notify{BackendLogID: &blid})
b.send(ipn.Notify{Prefs: prefs})
if !loggedOut && b.hasNodeKey() {
// Even if !WantRunning, we should verify our key, if there
// is one. If you want tailscaled to be completely idle,
// use logout instead.
cc.Login(nil, controlclient.LoginDefault)
}
b.stateMachine()
return nil
}
// updateFilter updates the packet filter in wgengine based on the
// given netMap and user preferences.
func (b *LocalBackend) updateFilter(netMap *netmap.NetworkMap, prefs *ipn.Prefs) {
// NOTE(danderson): keep change detection as the first thing in
// this function. Don't try to optimize by returning early, more
// likely than not you'll just end up breaking the change
// detection and end up with the wrong filter installed. This is
// quite hard to debug, so save yourself the trouble.
var (
haveNetmap = netMap != nil
addrs []netaddr.IPPrefix
packetFilter []filter.Match
localNetsB netaddr.IPSetBuilder
logNetsB netaddr.IPSetBuilder
shieldsUp = prefs == nil || prefs.ShieldsUp // Be conservative when not ready
)
// Log traffic for Tailscale IPs.
logNetsB.AddPrefix(tsaddr.CGNATRange())
logNetsB.AddPrefix(tsaddr.TailscaleULARange())
logNetsB.RemovePrefix(tsaddr.ChromeOSVMRange())
if haveNetmap {
addrs = netMap.Addresses
for _, p := range addrs {
localNetsB.AddPrefix(p)
}
packetFilter = netMap.PacketFilter
}
if prefs != nil {
for _, r := range prefs.AdvertiseRoutes {
if r.Bits() == 0 {
// When offering a default route to the world, we
// filter out locally reachable LANs, so that the
// default route effectively appears to be a "guest
// wifi": you get internet access, but to additionally
// get LAN access the LAN(s) need to be offered
// explicitly as well.
localInterfaceRoutes, hostIPs, err := interfaceRoutes()
if err != nil {
b.logf("getting local interface routes: %v", err)
continue
}
s, err := shrinkDefaultRoute(r, localInterfaceRoutes, hostIPs)
if err != nil {
b.logf("computing default route filter: %v", err)
continue
}
localNetsB.AddSet(s)
} else {
localNetsB.AddPrefix(r)
// When advertising a non-default route, we assume
// this is a corporate subnet that should be present
// in the audit logs.
logNetsB.AddPrefix(r)
}
}
}
localNets, _ := localNetsB.IPSet()
logNets, _ := logNetsB.IPSet()
changed := deephash.Update(&b.filterHash, haveNetmap, addrs, packetFilter, localNets.Ranges(), logNets.Ranges(), shieldsUp)
if !changed {
return
}
if !haveNetmap {
b.logf("netmap packet filter: (not ready yet)")
b.setFilter(filter.NewAllowNone(b.logf, logNets))
return
}
oldFilter := b.e.GetFilter()
if shieldsUp {
b.logf("netmap packet filter: (shields up)")
b.setFilter(filter.NewShieldsUpFilter(localNets, logNets, oldFilter, b.logf))
} else {
b.logf("netmap packet filter: %v filters", len(packetFilter))
b.setFilter(filter.New(packetFilter, localNets, logNets, oldFilter, b.logf))
}
}
func (b *LocalBackend) setFilter(f *filter.Filter) {
b.filterAtomic.Store(f)
b.e.SetFilter(f)
}
var removeFromDefaultRoute = []netaddr.IPPrefix{
// RFC1918 LAN ranges
netaddr.MustParseIPPrefix("192.168.0.0/16"),
netaddr.MustParseIPPrefix("172.16.0.0/12"),
netaddr.MustParseIPPrefix("10.0.0.0/8"),
// IPv4 link-local
netaddr.MustParseIPPrefix("169.254.0.0/16"),
// IPv4 multicast
netaddr.MustParseIPPrefix("224.0.0.0/4"),
// Tailscale IPv4 range
tsaddr.CGNATRange(),
// IPv6 Link-local addresses
netaddr.MustParseIPPrefix("fe80::/10"),
// IPv6 multicast
netaddr.MustParseIPPrefix("ff00::/8"),
// Tailscale IPv6 range
tsaddr.TailscaleULARange(),
}
// internalAndExternalInterfaces splits interface routes into "internal"
// and "external" sets. Internal routes are those of virtual ethernet
// network interfaces used by guest VMs and containers, such as WSL and
// Docker.
//
// Given that "internal" routes don't leave the device, we choose to
// trust them more, allowing access to them when an Exit Node is enabled.
func internalAndExternalInterfaces() (internal, external []netaddr.IPPrefix, err error) {
il, err := interfaces.GetList()
if err != nil {
return nil, nil, err
}
return internalAndExternalInterfacesFrom(il, runtime.GOOS)
}
func internalAndExternalInterfacesFrom(il interfaces.List, goos string) (internal, external []netaddr.IPPrefix, err error) {
// We use an IPSetBuilder here to canonicalize the prefixes
// and to remove any duplicate entries.
var internalBuilder, externalBuilder netaddr.IPSetBuilder
if err := il.ForeachInterfaceAddress(func(iface interfaces.Interface, pfx netaddr.IPPrefix) {
if tsaddr.IsTailscaleIP(pfx.IP()) {
return
}
if pfx.IsSingleIP() {
return
}
if iface.IsLoopback() {
internalBuilder.AddPrefix(pfx)
return
}
if goos == "windows" {
// Windows Hyper-V prefixes all MAC addresses with 00:15:5d.
// https://docs.microsoft.com/en-us/troubleshoot/windows-server/virtualization/default-limit-256-dynamic-mac-addresses
//
// This includes WSL2 vEthernet.
// Importantly: by default WSL2 /etc/resolv.conf points to
// a stub resolver running on the host vEthernet IP.
// So enabling exit nodes with the default tailnet
// configuration breaks WSL2 DNS without this.
mac := iface.Interface.HardwareAddr
if len(mac) == 6 && mac[0] == 0x00 && mac[1] == 0x15 && mac[2] == 0x5d {
internalBuilder.AddPrefix(pfx)
return
}
}
externalBuilder.AddPrefix(pfx)
}); err != nil {
return nil, nil, err
}
iSet, err := internalBuilder.IPSet()
if err != nil {
return nil, nil, err
}
eSet, err := externalBuilder.IPSet()
if err != nil {
return nil, nil, err
}
return iSet.Prefixes(), eSet.Prefixes(), nil
}
func interfaceRoutes() (ips *netaddr.IPSet, hostIPs []netaddr.IP, err error) {
var b netaddr.IPSetBuilder
if err := interfaces.ForeachInterfaceAddress(func(_ interfaces.Interface, pfx netaddr.IPPrefix) {
if tsaddr.IsTailscaleIP(pfx.IP()) {
return
}
if pfx.IsSingleIP() {
return
}
hostIPs = append(hostIPs, pfx.IP())
b.AddPrefix(pfx)
}); err != nil {
return nil, nil, err
}
ipSet, _ := b.IPSet()
return ipSet, hostIPs, nil
}
// shrinkDefaultRoute returns an IPSet representing the IPs in route,
// minus those in removeFromDefaultRoute and localInterfaceRoutes,
// plus the IPs in hostIPs.
func shrinkDefaultRoute(route netaddr.IPPrefix, localInterfaceRoutes *netaddr.IPSet, hostIPs []netaddr.IP) (*netaddr.IPSet, error) {
var b netaddr.IPSetBuilder
// Add the default route.
b.AddPrefix(route)
// Remove the local interface routes.
b.RemoveSet(localInterfaceRoutes)
// Having removed all the LAN subnets, re-add the hosts's own
// IPs. It's fine for clients to connect to an exit node's public
// IP address, just not the attached subnet.
//
// Truly forbidden subnets (in removeFromDefaultRoute) will still
// be stripped back out by the next step.
for _, ip := range hostIPs {
if route.Contains(ip) {
b.Add(ip)
}
}
for _, pfx := range removeFromDefaultRoute {
b.RemovePrefix(pfx)
}
return b.IPSet()
}
// dnsCIDRsEqual determines whether two CIDR lists are equal
// for DNS map construction purposes (that is, only the first entry counts).
func dnsCIDRsEqual(newAddr, oldAddr []netaddr.IPPrefix) bool {
if len(newAddr) != len(oldAddr) {
return false
}
if len(newAddr) == 0 || newAddr[0] == oldAddr[0] {
return true
}
return false
}
// dnsMapsEqual determines whether the new and the old network map
// induce the same DNS map. It does so without allocating memory,
// at the expense of giving false negatives if peers are reordered.
func dnsMapsEqual(new, old *netmap.NetworkMap) bool {
if (old == nil) != (new == nil) {
return false
}
if old == nil && new == nil {
return true
}
if len(new.Peers) != len(old.Peers) {
return false
}
if new.Name != old.Name {
return false
}
if !dnsCIDRsEqual(new.Addresses, old.Addresses) {
return false
}
for i, newPeer := range new.Peers {
oldPeer := old.Peers[i]
if newPeer.Name != oldPeer.Name {
return false
}
if !dnsCIDRsEqual(newPeer.Addresses, oldPeer.Addresses) {
return false
}
}
return true
}
// readPoller is a goroutine that receives service lists from
// b.portpoll and propagates them into the controlclient's HostInfo.
func (b *LocalBackend) readPoller() {
n := 0
for {
ports, ok := <-b.portpoll.C
if !ok {
return
}
sl := []tailcfg.Service{}
for _, p := range ports {
s := tailcfg.Service{
Proto: tailcfg.ServiceProto(p.Proto),
Port: p.Port,
Description: p.Process,
}
if policy.IsInterestingService(s, version.OS()) {
sl = append(sl, s)
}
}
b.mu.Lock()
if b.hostinfo == nil {
b.hostinfo = new(tailcfg.Hostinfo)
}
b.hostinfo.Services = sl
hi := b.hostinfo
b.mu.Unlock()
b.doSetHostinfoFilterServices(hi)
n++
if n == 1 {
close(b.gotPortPollRes)
}
}
}
// send delivers n to the connected frontend. If no frontend is
// connected, the notification is dropped without being delivered.
func (b *LocalBackend) send(n ipn.Notify) {
b.mu.Lock()
notifyFunc := b.notify
apiSrv := b.peerAPIServer
b.mu.Unlock()
if notifyFunc == nil {
return
}
if apiSrv.hasFilesWaiting() {
n.FilesWaiting = &empty.Message{}
}
n.Version = version.Long
notifyFunc(n)
}
func (b *LocalBackend) sendFileNotify() {
var n ipn.Notify
b.mu.Lock()
notifyFunc := b.notify
apiSrv := b.peerAPIServer
if notifyFunc == nil || apiSrv == nil {
b.mu.Unlock()
return
}
// Make sure we always set n.IncomingFiles non-nil so it gets encoded
// in JSON to clients. They distinguish between empty and non-nil
// to know whether a Notify should be able about files.
n.IncomingFiles = make([]ipn.PartialFile, 0)
for f := range b.incomingFiles {
n.IncomingFiles = append(n.IncomingFiles, f.PartialFile())
}
b.mu.Unlock()
sort.Slice(n.IncomingFiles, func(i, j int) bool {
return n.IncomingFiles[i].Started.Before(n.IncomingFiles[j].Started)
})
b.send(n)
}
// popBrowserAuthNow shuts down the data plane and sends an auth URL
// to the connected frontend, if any.
func (b *LocalBackend) popBrowserAuthNow() {
b.mu.Lock()
url := b.authURL
b.interact = false
b.authURL = "" // but NOT clearing authURLSticky
b.mu.Unlock()
b.logf("popBrowserAuthNow: url=%v", url != "")
b.blockEngineUpdates(true)
b.stopEngineAndWait()
b.send(ipn.Notify{BrowseToURL: &url})
if b.State() == ipn.Running {
b.enterState(ipn.Starting)
}
}
// For testing lazy machine key generation.
var panicOnMachineKeyGeneration, _ = strconv.ParseBool(os.Getenv("TS_DEBUG_PANIC_MACHINE_KEY"))
func (b *LocalBackend) createGetMachinePrivateKeyFunc() func() (key.MachinePrivate, error) {
var cache atomic.Value
return func() (key.MachinePrivate, error) {
if panicOnMachineKeyGeneration {
panic("machine key generated")
}
if v, ok := cache.Load().(key.MachinePrivate); ok {
return v, nil
}
b.mu.Lock()
defer b.mu.Unlock()
if v, ok := cache.Load().(key.MachinePrivate); ok {
return v, nil
}
if err := b.initMachineKeyLocked(); err != nil {
return key.MachinePrivate{}, err
}
cache.Store(b.machinePrivKey)
return b.machinePrivKey, nil
}
}
// initMachineKeyLocked is called to initialize b.machinePrivKey.
//
// b.prefs must already be initialized.
// b.stateKey should be set too, but just for nicer log messages.
// b.mu must be held.
func (b *LocalBackend) initMachineKeyLocked() (err error) {
if !b.machinePrivKey.IsZero() {
// Already set.
return nil
}
var legacyMachineKey key.MachinePrivate
if b.prefs.Persist != nil {
legacyMachineKey = b.prefs.Persist.LegacyFrontendPrivateMachineKey
}
keyText, err := b.store.ReadState(ipn.MachineKeyStateKey)
if err == nil {
if err := b.machinePrivKey.UnmarshalText(keyText); err != nil {
return fmt.Errorf("invalid key in %s key of %v: %w", ipn.MachineKeyStateKey, b.store, err)
}
if b.machinePrivKey.IsZero() {
return fmt.Errorf("invalid zero key stored in %v key of %v", ipn.MachineKeyStateKey, b.store)
}
if !legacyMachineKey.IsZero() && !legacyMachineKey.Equal(b.machinePrivKey) {
b.logf("frontend-provided legacy machine key ignored; used value from server state")
}
return nil
}
if err != ipn.ErrStateNotExist {
return fmt.Errorf("error reading %v key of %v: %w", ipn.MachineKeyStateKey, b.store, err)
}
// If we didn't find one already on disk and the prefs already
// have a legacy machine key, use that. Otherwise generate a
// new one.
if !legacyMachineKey.IsZero() {
if b.stateKey == "" {
b.logf("using frontend-provided legacy machine key")
} else {
b.logf("using legacy machine key from state key %q", b.stateKey)
}
b.machinePrivKey = legacyMachineKey
} else {
b.logf("generating new machine key")
b.machinePrivKey = key.NewMachine()
}
keyText, _ = b.machinePrivKey.MarshalText()
if err := b.store.WriteState(ipn.MachineKeyStateKey, keyText); err != nil {
b.logf("error writing machine key to store: %v", err)
return err
}
b.logf("machine key written to store")
return nil
}
// writeServerModeStartState stores the ServerModeStartKey value based on the current
// user and prefs. If userID is blank or prefs is blank, no work is done.
//
// b.mu may either be held or not.
func (b *LocalBackend) writeServerModeStartState(userID string, prefs *ipn.Prefs) {
if userID == "" || prefs == nil {
return
}
if prefs.ForceDaemon {
stateKey := ipn.StateKey("user-" + userID)
if err := b.store.WriteState(ipn.ServerModeStartKey, []byte(stateKey)); err != nil {
b.logf("WriteState error: %v", err)
}
// It's important we do this here too, even if it looks
// redundant with the one in the 'if stateKey != ""'
// check block above. That one won't fire in the case
// where the Windows client started up in client mode.
// This happens when we transition into server mode:
if err := b.store.WriteState(stateKey, prefs.ToBytes()); err != nil {
b.logf("WriteState error: %v", err)
}
} else {
if err := b.store.WriteState(ipn.ServerModeStartKey, nil); err != nil {
b.logf("WriteState error: %v", err)
}
}
}
// loadStateLocked sets b.prefs and b.stateKey based on a complex
// combination of key, prefs, and legacyPath. b.mu must be held when
// calling.
func (b *LocalBackend) loadStateLocked(key ipn.StateKey, prefs *ipn.Prefs) (err error) {
if prefs == nil && key == "" {
panic("state key and prefs are both unset")
}
// Optimistically set stateKey (for initMachineKeyLocked's
// logging), but revert it if we return an error so a later SetPrefs
// call can't pick it up if it's bogus.
b.stateKey = key
defer func() {
if err != nil {
b.stateKey = ""
}
}()
if key == "" {
// Frontend owns the state, we just need to obey it.
//
// If the frontend (e.g. on Windows) supplied the
// optional/legacy machine key then it's used as the
// value instead of making up a new one.
b.logf("using frontend prefs: %s", prefs.Pretty())
b.prefs = prefs.Clone()
b.writeServerModeStartState(b.userID, b.prefs)
return nil
}
if prefs != nil {
// Backend owns the state, but frontend is trying to migrate
// state into the backend.
b.logf("importing frontend prefs into backend store; frontend prefs: %s", prefs.Pretty())
if err := b.store.WriteState(key, prefs.ToBytes()); err != nil {
return fmt.Errorf("store.WriteState: %v", err)
}
}
b.logf("using backend prefs")
bs, err := b.store.ReadState(key)
switch {
case errors.Is(err, ipn.ErrStateNotExist):
b.prefs = ipn.NewPrefs()
b.prefs.WantRunning = false
b.logf("created empty state for %q: %s", key, b.prefs.Pretty())
return nil
case err != nil:
return fmt.Errorf("store.ReadState(%q): %v", key, err)
}
b.prefs, err = ipn.PrefsFromBytes(bs, false)
if err != nil {
return fmt.Errorf("PrefsFromBytes: %v", err)
}
// On mobile platforms, ignore any old stored preferences for
// https://login.tailscale.com as the control server that
// would override the new default of controlplane.tailscale.com.
// This makes sure that mobile clients go through the new
// frontends where we're (2021-10-02) doing battery
// optimization work ahead of turning down the old backends.
// TODO(bradfitz): make this the default for all platforms
// later. But mobile is a relatively small chunk (compared to
// Linux, Windows, macOS) and moving mobile early for battery
// gains is nice.
switch runtime.GOOS {
case "android", "ios":
if b.prefs != nil && b.prefs.ControlURL != "" &&
b.prefs.ControlURL != ipn.DefaultControlURL &&
ipn.IsLoginServerSynonym(b.prefs.ControlURL) {
b.prefs.ControlURL = ""
}
}
b.logf("backend prefs for %q: %s", key, b.prefs.Pretty())
return nil
}
// State returns the backend state machine's current state.
func (b *LocalBackend) State() ipn.State {
b.mu.Lock()
defer b.mu.Unlock()
return b.state
}
func (b *LocalBackend) InServerMode() bool {
b.mu.Lock()
defer b.mu.Unlock()
return b.inServerMode
}
// Login implements Backend.
func (b *LocalBackend) Login(token *tailcfg.Oauth2Token) {
b.mu.Lock()
b.assertClientLocked()
cc := b.cc
b.mu.Unlock()
cc.Login(token, controlclient.LoginInteractive)
}
// StartLoginInteractive implements Backend. It requests a new
// interactive login from controlclient, unless such a flow is already
// in progress, in which case StartLoginInteractive attempts to pick
// up the in-progress flow where it left off.
func (b *LocalBackend) StartLoginInteractive() {
b.mu.Lock()
b.assertClientLocked()
b.interact = true
url := b.authURL
cc := b.cc
b.mu.Unlock()
b.logf("StartLoginInteractive: url=%v", url != "")
if url != "" {
b.popBrowserAuthNow()
} else {
flags := controlclient.LoginInteractive
if runtime.GOOS == "js" {
// The js/wasm client has no state storage so for now
// treat all interactive logins as ephemeral.
// TODO(bradfitz): if we start using browser LocalStorage
// or something, then rethink this.
flags |= controlclient.LoginEphemeral
}
cc.Login(nil, flags)
}
}
// FakeExpireAfter implements Backend.
func (b *LocalBackend) FakeExpireAfter(x time.Duration) {
b.logf("FakeExpireAfter: %v", x)
b.mu.Lock()
defer b.mu.Unlock()
if b.netMap == nil {
return
}
// This function is called very rarely,
// so we prefer to fully copy the netmap over introducing in-place modification here.
mapCopy := *b.netMap
e := mapCopy.Expiry
if e.IsZero() || time.Until(e) > x {
mapCopy.Expiry = time.Now().Add(x)
}
b.setNetMapLocked(&mapCopy)
b.send(ipn.Notify{NetMap: b.netMap})
}
func (b *LocalBackend) Ping(ipStr string, useTSMP bool) {
ip, err := netaddr.ParseIP(ipStr)
if err != nil {
b.logf("ignoring Ping request to invalid IP %q", ipStr)
return
}
b.e.Ping(ip, useTSMP, func(pr *ipnstate.PingResult) {
b.send(ipn.Notify{PingResult: pr})
})
}
// parseWgStatusLocked returns an EngineStatus based on s.
//
// b.mu must be held; mostly because the caller is about to anyway, and doing so
// gives us slightly better guarantees about the two peers stats lines not
// being intermixed if there are concurrent calls to our caller.
func (b *LocalBackend) parseWgStatusLocked(s *wgengine.Status) (ret ipn.EngineStatus) {
var peerStats, peerKeys strings.Builder
ret.LiveDERPs = s.DERPs
ret.LivePeers = map[key.NodePublic]ipnstate.PeerStatusLite{}
for _, p := range s.Peers {
if !p.LastHandshake.IsZero() {
fmt.Fprintf(&peerStats, "%d/%d ", p.RxBytes, p.TxBytes)
fmt.Fprintf(&peerKeys, "%s ", p.NodeKey.ShortString())
ret.NumLive++
ret.LivePeers[p.NodeKey] = p
}
ret.RBytes += p.RxBytes
ret.WBytes += p.TxBytes
}
// [GRINDER STATS LINES] - please don't remove (used for log parsing)
if peerStats.Len() > 0 {
b.keyLogf("[v1] peer keys: %s", strings.TrimSpace(peerKeys.String()))
b.statsLogf("[v1] v%v peers: %v", version.Long, strings.TrimSpace(peerStats.String()))
}
return ret
}
// shouldUploadServices reports whether this node should include services
// in Hostinfo. When the user preferences currently request "shields up"
// mode, all inbound connections are refused, so services are not reported.
// Otherwise, shouldUploadServices respects NetMap.CollectServices.
func (b *LocalBackend) shouldUploadServices() bool {
b.mu.Lock()
defer b.mu.Unlock()
if b.prefs == nil || b.netMap == nil {
return false // default to safest setting
}
return !b.prefs.ShieldsUp && b.netMap.CollectServices
}
func (b *LocalBackend) SetCurrentUserID(uid string) {
b.mu.Lock()
b.userID = uid
b.mu.Unlock()
}
func (b *LocalBackend) EditPrefs(mp *ipn.MaskedPrefs) (*ipn.Prefs, error) {
b.mu.Lock()
p0 := b.prefs.Clone()
p1 := b.prefs.Clone()
p1.ApplyEdits(mp)
if p1.Equals(p0) {
b.mu.Unlock()
return p1, nil
}
b.logf("EditPrefs: %v", mp.Pretty())
b.setPrefsLockedOnEntry("EditPrefs", p1) // does a b.mu.Unlock
// Note: don't perform any actions for the new prefs here. Not
// every prefs change goes through EditPrefs. Put your actions
// in setPrefsLocksOnEntry instead.
return p1, nil
}
// SetPrefs saves new user preferences and propagates them throughout
// the system. Implements Backend.
func (b *LocalBackend) SetPrefs(newp *ipn.Prefs) {
if newp == nil {
panic("SetPrefs got nil prefs")
}
b.mu.Lock()
b.setPrefsLockedOnEntry("SetPrefs", newp)
}
// setPrefsLockedOnEntry requires b.mu be held to call it, but it
// unlocks b.mu when done. newp ownership passes to this function.
func (b *LocalBackend) setPrefsLockedOnEntry(caller string, newp *ipn.Prefs) {
netMap := b.netMap
stateKey := b.stateKey
oldp := b.prefs
newp.Persist = oldp.Persist // caller isn't allowed to override this
b.prefs = newp
// findExitNodeIDLocked returns whether it updated b.prefs, but
// everything in this function treats b.prefs as completely new
// anyway. No-op if no exit node resolution is needed.
b.findExitNodeIDLocked(netMap)
b.inServerMode = newp.ForceDaemon
// We do this to avoid holding the lock while doing everything else.
newp = b.prefs.Clone()
oldHi := b.hostinfo
newHi := oldHi.Clone()
applyPrefsToHostinfo(newHi, newp)
b.hostinfo = newHi
hostInfoChanged := !oldHi.Equal(newHi)
userID := b.userID
cc := b.cc
b.mu.Unlock()
if stateKey != "" {
if err := b.store.WriteState(stateKey, newp.ToBytes()); err != nil {
b.logf("failed to save new controlclient state: %v", err)
}
}
b.writeServerModeStartState(userID, newp)
// [GRINDER STATS LINE] - please don't remove (used for log parsing)
if caller == "SetPrefs" {
b.logf("SetPrefs: %v", newp.Pretty())
}
if netMap != nil {
if login := netMap.UserProfiles[netMap.User].LoginName; login != "" {
if newp.Persist == nil {
b.logf("active login: %s", login)
} else if newp.Persist.LoginName != login {
// Corp issue 461: sometimes the wrong prefs are
// logged; the frontend isn't always getting
// notified (to update its prefs/persist) on
// account switch. Log this while we figure it
// out.
b.logf("active login: %q ([unexpected] corp#461, not %q)", newp.Persist.LoginName, login)
}
}
}
if oldp.ShieldsUp != newp.ShieldsUp || hostInfoChanged {
b.doSetHostinfoFilterServices(newHi)
}
b.updateFilter(netMap, newp)
if netMap != nil {
b.e.SetDERPMap(netMap.DERPMap)
}
if !oldp.WantRunning && newp.WantRunning {
b.logf("transitioning to running; doing Login...")
cc.Login(nil, controlclient.LoginDefault)
}
if oldp.WantRunning != newp.WantRunning {
b.stateMachine()
} else {
b.authReconfig()
}
b.send(ipn.Notify{Prefs: newp})
}
func (b *LocalBackend) getPeerAPIPortForTSMPPing(ip netaddr.IP) (port uint16, ok bool) {
b.mu.Lock()
defer b.mu.Unlock()
for _, pln := range b.peerAPIListeners {
if pln.ip == ip {
return uint16(pln.port), true
}
}
return 0, false
}
func (b *LocalBackend) peerAPIServicesLocked() (ret []tailcfg.Service) {
for _, pln := range b.peerAPIListeners {
proto := tailcfg.PeerAPI4
if pln.ip.Is6() {
proto = tailcfg.PeerAPI6
}
ret = append(ret, tailcfg.Service{
Proto: proto,
Port: uint16(pln.port),
})
}
switch runtime.GOOS {
case "linux", "freebsd", "openbsd", "illumos", "darwin", "windows":
// These are the platforms currently supported by
// net/dns/resolver/tsdns.go:Resolver.HandleExitNodeDNSQuery.
ret = append(ret, tailcfg.Service{
Proto: tailcfg.PeerAPIDNS,
Port: 1, // version
})
}
return ret
}
// doSetHostinfoFilterServices calls SetHostinfo on the controlclient,
// possibly after mangling the given hostinfo.
//
// TODO(danderson): we shouldn't be mangling hostinfo here after
// painstakingly constructing it in twelvety other places.
func (b *LocalBackend) doSetHostinfoFilterServices(hi *tailcfg.Hostinfo) {
if hi == nil {
b.logf("[unexpected] doSetHostinfoFilterServices with nil hostinfo")
return
}
b.mu.Lock()
cc := b.cc
if cc == nil {
// Control client isn't up yet.
b.mu.Unlock()
return
}
peerAPIServices := b.peerAPIServicesLocked()
b.mu.Unlock()
// Make a shallow copy of hostinfo so we can mutate
// at the Service field.
hi2 := *hi // shallow copy
if !b.shouldUploadServices() {
hi2.Services = []tailcfg.Service{}
}
// Don't mutate hi.Service's underlying array. Append to
// the slice with no free capacity.
c := len(hi2.Services)
hi2.Services = append(hi2.Services[:c:c], peerAPIServices...)
cc.SetHostinfo(&hi2)
}
// NetMap returns the latest cached network map received from
// controlclient, or nil if no network map was received yet.
func (b *LocalBackend) NetMap() *netmap.NetworkMap {
b.mu.Lock()
defer b.mu.Unlock()
return b.netMap
}
func (b *LocalBackend) isEngineBlocked() bool {
b.mu.Lock()
defer b.mu.Unlock()
return b.blocked
}
// blockEngineUpdate sets b.blocked to block, while holding b.mu. Its
// indirect effect is to turn b.authReconfig() into a no-op if block
// is true.
func (b *LocalBackend) blockEngineUpdates(block bool) {
b.logf("blockEngineUpdates(%v)", block)
b.mu.Lock()
b.blocked = block
b.mu.Unlock()
}
// authReconfig pushes a new configuration into wgengine, if engine
// updates are not currently blocked, based on the cached netmap and
// user prefs.
func (b *LocalBackend) authReconfig() {
b.mu.Lock()
blocked := b.blocked
prefs := b.prefs
nm := b.netMap
hasPAC := b.prevIfState.HasPAC()
disableSubnetsIfPAC := nm != nil && nm.Debug != nil && nm.Debug.DisableSubnetsIfPAC.EqualBool(true)
b.mu.Unlock()
if blocked {
b.logf("authReconfig: blocked, skipping.")
return
}
if nm == nil {
b.logf("authReconfig: netmap not yet valid. Skipping.")
return
}
if !prefs.WantRunning {
b.logf("authReconfig: skipping because !WantRunning.")
return
}
var flags netmap.WGConfigFlags
if prefs.RouteAll {
flags |= netmap.AllowSubnetRoutes
}
if prefs.AllowSingleHosts {
flags |= netmap.AllowSingleHosts
}
if hasPAC && disableSubnetsIfPAC {
if flags&netmap.AllowSubnetRoutes != 0 {
b.logf("authReconfig: have PAC; disabling subnet routes")
flags &^= netmap.AllowSubnetRoutes
}
}
// Keep the dialer updated about whether we're supposed to use
// an exit node's DNS server (so SOCKS5/HTTP outgoing dials
// can use it for name resolution)
if dohURL, ok := exitNodeCanProxyDNS(nm, prefs.ExitNodeID); ok {
b.dialer.SetExitDNSDoH(dohURL)
} else {
b.dialer.SetExitDNSDoH("")
}
cfg, err := nmcfg.WGCfg(nm, b.logf, flags, prefs.ExitNodeID)
if err != nil {
b.logf("wgcfg: %v", err)
return
}
rcfg := b.routerConfig(cfg, prefs)
dcfg := dnsConfigForNetmap(nm, prefs, b.logf, version.OS())
err = b.e.Reconfig(cfg, rcfg, dcfg, nm.Debug)
if err == wgengine.ErrNoChanges {
return
}
b.logf("[v1] authReconfig: ra=%v dns=%v 0x%02x: %v", prefs.RouteAll, prefs.CorpDNS, flags, err)
b.initPeerAPIListener()
}
// dnsConfigForNetmap returns a *dns.Config for the given netmap,
// prefs, and client OS version.
//
// The versionOS is a Tailscale-style version ("iOS", "macOS") and not
// a runtime.GOOS.
func dnsConfigForNetmap(nm *netmap.NetworkMap, prefs *ipn.Prefs, logf logger.Logf, versionOS string) *dns.Config {
dcfg := &dns.Config{
Routes: map[dnsname.FQDN][]dnstype.Resolver{},
Hosts: map[dnsname.FQDN][]netaddr.IP{},
}
// selfV6Only is whether we only have IPv6 addresses ourselves.
selfV6Only := tsaddr.PrefixesContainsFunc(nm.Addresses, tsaddr.PrefixIs6) &&
!tsaddr.PrefixesContainsFunc(nm.Addresses, tsaddr.PrefixIs4)
dcfg.OnlyIPv6 = selfV6Only
// Populate MagicDNS records. We do this unconditionally so that
// quad-100 can always respond to MagicDNS queries, even if the OS
// isn't configured to make MagicDNS resolution truly
// magic. Details in
// https://github.com/tailscale/tailscale/issues/1886.
set := func(name string, addrs []netaddr.IPPrefix) {
if len(addrs) == 0 || name == "" {
return
}
fqdn, err := dnsname.ToFQDN(name)
if err != nil {
return // TODO: propagate error?
}
have4 := tsaddr.PrefixesContainsFunc(addrs, tsaddr.PrefixIs4)
var ips []netaddr.IP
for _, addr := range addrs {
if selfV6Only {
if addr.IP().Is6() {
ips = append(ips, addr.IP())
}
continue
}
// If this node has an IPv4 address, then
// remove peers' IPv6 addresses for now, as we
// don't guarantee that the peer node actually
// can speak IPv6 correctly.
//
// https://github.com/tailscale/tailscale/issues/1152
// tracks adding the right capability reporting to
// enable AAAA in MagicDNS.
if addr.IP().Is6() && have4 {
continue
}
ips = append(ips, addr.IP())
}
dcfg.Hosts[fqdn] = ips
}
set(nm.Name, nm.Addresses)
for _, peer := range nm.Peers {
set(peer.Name, peer.Addresses)
}
for _, rec := range nm.DNS.ExtraRecords {
switch rec.Type {
case "", "A", "AAAA":
// Treat these all the same for now: infer from the value
default:
// TODO: more
continue
}
ip, err := netaddr.ParseIP(rec.Value)
if err != nil {
// Ignore.
continue
}
fqdn, err := dnsname.ToFQDN(rec.Name)
if err != nil {
continue
}
dcfg.Hosts[fqdn] = append(dcfg.Hosts[fqdn], ip)
}
if !prefs.CorpDNS {
return dcfg
}
for _, dom := range nm.DNS.Domains {
fqdn, err := dnsname.ToFQDN(dom)
if err != nil {
logf("[unexpected] non-FQDN search domain %q", dom)
}
dcfg.SearchDomains = append(dcfg.SearchDomains, fqdn)
}
if nm.DNS.Proxied { // actually means "enable MagicDNS"
for _, dom := range magicDNSRootDomains(nm) {
dcfg.Routes[dom] = nil // resolve internally with dcfg.Hosts
}
}
addDefault := func(resolvers []dnstype.Resolver) {
for _, r := range resolvers {
dcfg.DefaultResolvers = append(dcfg.DefaultResolvers, normalizeResolver(r))
}
}
// If we're using an exit node and that exit node is new enough (1.19.x+)
// to run a DoH DNS proxy, then send all our DNS traffic through it.
if dohURL, ok := exitNodeCanProxyDNS(nm, prefs.ExitNodeID); ok {
addDefault([]dnstype.Resolver{{Addr: dohURL}})
return dcfg
}
addDefault(nm.DNS.Resolvers)
for suffix, resolvers := range nm.DNS.Routes {
fqdn, err := dnsname.ToFQDN(suffix)
if err != nil {
logf("[unexpected] non-FQDN route suffix %q", suffix)
}
// Create map entry even if len(resolvers) == 0; Issue 2706.
// This lets the control plane send ExtraRecords for which we
// can authoritatively answer "name not exists" for when the
// control plane also sends this explicit but empty route
// making it as something we handle.
//
// While we're already populating it, might as well size the
// slice appropriately.
dcfg.Routes[fqdn] = make([]dnstype.Resolver, 0, len(resolvers))
for _, r := range resolvers {
dcfg.Routes[fqdn] = append(dcfg.Routes[fqdn], normalizeResolver(r))
}
}
// Set FallbackResolvers as the default resolvers in the
// scenarios that can't handle a purely split-DNS config. See
// https://github.com/tailscale/tailscale/issues/1743 for
// details.
switch {
case len(dcfg.DefaultResolvers) != 0:
// Default resolvers already set.
case !prefs.ExitNodeID.IsZero():
// When using exit nodes, it's very likely the LAN
// resolvers will become unreachable. So, force use of the
// fallback resolvers until we implement DNS forwarding to
// exit nodes.
//
// This is especially important on Apple OSes, where
// adding the default route to the tunnel interface makes
// it "primary", and we MUST provide VPN-sourced DNS
// settings or we break all DNS resolution.
//
// https://github.com/tailscale/tailscale/issues/1713
addDefault(nm.DNS.FallbackResolvers)
case len(dcfg.Routes) == 0:
// No settings requiring split DNS, no problem.
}
return dcfg
}
func normalizeResolver(cfg dnstype.Resolver) dnstype.Resolver {
if ip, err := netaddr.ParseIP(cfg.Addr); err == nil {
// Add 53 here for bare IPs for consistency with previous data type.
return dnstype.Resolver{
Addr: netaddr.IPPortFrom(ip, 53).String(),
}
}
return cfg
}
// SetVarRoot sets the root directory of Tailscale's writable
// storage area . (e.g. "/var/lib/tailscale")
//
// It should only be called before the LocalBackend is used.
func (b *LocalBackend) SetVarRoot(dir string) {
b.varRoot = dir
}
// TailscaleVarRoot returns the root directory of Tailscale's writable
// storage area. (e.g. "/var/lib/tailscale")
//
// It returns an empty string if there's no configured or discovered
// location.
func (b *LocalBackend) TailscaleVarRoot() string {
if b.varRoot != "" {
return b.varRoot
}
switch runtime.GOOS {
case "ios", "android", "darwin":
dir, _ := paths.AppSharedDir.Load().(string)
return dir
}
return ""
}
func (b *LocalBackend) fileRootLocked(uid tailcfg.UserID) string {
if v := b.directFileRoot; v != "" {
return v
}
varRoot := b.TailscaleVarRoot()
if varRoot == "" {
b.logf("Taildrop disabled; no state directory")
return ""
}
baseDir := fmt.Sprintf("%s-uid-%d",
strings.ReplaceAll(b.activeLogin, "@", "-"),
uid)
dir := filepath.Join(varRoot, "files", baseDir)
if err := os.MkdirAll(dir, 0700); err != nil {
b.logf("Taildrop disabled; error making directory: %v", err)
return ""
}
return dir
}
// closePeerAPIListenersLocked closes any existing peer API listeners
// and clears out the peer API server state.
//
// It does not kick off any Hostinfo update with new services.
//
// b.mu must be held.
func (b *LocalBackend) closePeerAPIListenersLocked() {
b.peerAPIServer = nil
for _, pln := range b.peerAPIListeners {
pln.Close()
}
b.peerAPIListeners = nil
}
// peerAPIListenAsync is whether the operating system requires that we
// retry listening on the peerAPI ip/port for whatever reason.
//
// On Windows, see Issue 1620.
// On Android, see Issue 1960.
const peerAPIListenAsync = runtime.GOOS == "windows" || runtime.GOOS == "android"
func (b *LocalBackend) initPeerAPIListener() {
b.mu.Lock()
defer b.mu.Unlock()
if b.netMap == nil {
// We're called from authReconfig which checks that
// netMap is non-nil, but if a concurrent Logout,
// ResetForClientDisconnect, or Start happens when its
// mutex was released, the netMap could be
// nil'ed out (Issue 1996). Bail out early here if so.
return
}
if len(b.netMap.Addresses) == len(b.peerAPIListeners) {
allSame := true
for i, pln := range b.peerAPIListeners {
if pln.ip != b.netMap.Addresses[i].IP() {
allSame = false
break
}
}
if allSame {
// Nothing to do.
return
}
}
b.closePeerAPIListenersLocked()
selfNode := b.netMap.SelfNode
if len(b.netMap.Addresses) == 0 || selfNode == nil {
return
}
fileRoot := b.fileRootLocked(selfNode.User)
if fileRoot == "" {
b.logf("peerapi starting without Taildrop directory configured")
}
ps := &peerAPIServer{
b: b,
rootDir: fileRoot,
selfNode: selfNode,
directFileMode: b.directFileRoot != "",
directFileDoFinalRename: b.directFileDoFinalRename,
}
if re, ok := b.e.(wgengine.ResolvingEngine); ok {
if r, ok := re.GetResolver(); ok {
ps.resolver = r
}
}
b.peerAPIServer = ps
isNetstack := wgengine.IsNetstack(b.e)
for i, a := range b.netMap.Addresses {
var ln net.Listener
var err error
skipListen := i > 0 && isNetstack
if !skipListen {
ln, err = ps.listen(a.IP(), b.prevIfState)
if err != nil {
if peerAPIListenAsync {
// Expected. But we fix it later in linkChange
// ("peerAPIListeners too low").
continue
}
b.logf("[unexpected] peerapi listen(%q) error: %v", a.IP(), err)
continue
}
}
pln := &peerAPIListener{
ps: ps,
ip: a.IP(),
ln: ln, // nil for 2nd+ on netstack
lb: b,
}
if skipListen {
pln.port = b.peerAPIListeners[0].port
} else {
pln.port = ln.Addr().(*net.TCPAddr).Port
}
pln.urlStr = "http://" + net.JoinHostPort(a.IP().String(), strconv.Itoa(pln.port))
b.logf("peerapi: serving on %s", pln.urlStr)
go pln.serve()
b.peerAPIListeners = append(b.peerAPIListeners, pln)
}
go b.doSetHostinfoFilterServices(b.hostinfo.Clone())
}
// magicDNSRootDomains returns the subset of nm.DNS.Domains that are the search domains for MagicDNS.
func magicDNSRootDomains(nm *netmap.NetworkMap) []dnsname.FQDN {
if v := nm.MagicDNSSuffix(); v != "" {
fqdn, err := dnsname.ToFQDN(v)
if err != nil {
// TODO: propagate error
return nil
}
ret := []dnsname.FQDN{
fqdn,
dnsname.FQDN("0.e.1.a.c.5.1.1.a.7.d.f.ip6.arpa."),
}
for i := 64; i <= 127; i++ {
fqdn, err = dnsname.ToFQDN(fmt.Sprintf("%d.100.in-addr.arpa.", i))
if err != nil {
// TODO: propagate error
continue
}
ret = append(ret, fqdn)
}
return ret
}
return nil
}
var (
ipv4Default = netaddr.MustParseIPPrefix("0.0.0.0/0")
ipv6Default = netaddr.MustParseIPPrefix("::/0")
)
// peerRoutes returns the routerConfig.Routes to access peers.
// If there are over cgnatThreshold CGNAT routes, one big CGNAT route
// is used instead.
func peerRoutes(peers []wgcfg.Peer, cgnatThreshold int) (routes []netaddr.IPPrefix) {
tsULA := tsaddr.TailscaleULARange()
cgNAT := tsaddr.CGNATRange()
var didULA bool
var cgNATIPs []netaddr.IPPrefix
for _, peer := range peers {
for _, aip := range peer.AllowedIPs {
aip = unmapIPPrefix(aip)
// Only add the Tailscale IPv6 ULA once, if we see anybody using part of it.
if aip.IP().Is6() && aip.IsSingleIP() && tsULA.Contains(aip.IP()) {
if !didULA {
didULA = true
routes = append(routes, tsULA)
}
continue
}
if aip.IsSingleIP() && cgNAT.Contains(aip.IP()) {
cgNATIPs = append(cgNATIPs, aip)
} else {
routes = append(routes, aip)
}
}
}
if len(cgNATIPs) > cgnatThreshold {
// Probably the hello server. Just append one big route.
routes = append(routes, cgNAT)
} else {
routes = append(routes, cgNATIPs...)
}
return routes
}
// routerConfig produces a router.Config from a wireguard config and IPN prefs.
func (b *LocalBackend) routerConfig(cfg *wgcfg.Config, prefs *ipn.Prefs) *router.Config {
rs := &router.Config{
LocalAddrs: unmapIPPrefixes(cfg.Addresses),
SubnetRoutes: unmapIPPrefixes(prefs.AdvertiseRoutes),
SNATSubnetRoutes: !prefs.NoSNAT,
NetfilterMode: prefs.NetfilterMode,
Routes: peerRoutes(cfg.Peers, 10_000),
}
if distro.Get() == distro.Synology {
// Issue 1995: we don't use iptables on Synology.
rs.NetfilterMode = preftype.NetfilterOff
}
// Sanity check: we expect the control server to program both a v4
// and a v6 default route, if default routing is on. Fill in
// blackhole routes appropriately if we're missing some. This is
// likely to break some functionality, but if the user expressed a
// preference for routing remotely, we want to avoid leaking
// traffic at the expense of functionality.
if prefs.ExitNodeID != "" || !prefs.ExitNodeIP.IsZero() {
var default4, default6 bool
for _, route := range rs.Routes {
switch route {
case ipv4Default:
default4 = true
case ipv6Default:
default6 = true
}
if default4 && default6 {
break
}
}
if !default4 {
rs.Routes = append(rs.Routes, ipv4Default)
}
if !default6 {
rs.Routes = append(rs.Routes, ipv6Default)
}
internalIPs, externalIPs, err := internalAndExternalInterfaces()
if err != nil {
b.logf("failed to discover interface ips: %v", err)
}
if runtime.GOOS == "linux" || runtime.GOOS == "darwin" || runtime.GOOS == "windows" {
rs.LocalRoutes = internalIPs // unconditionally allow access to guest VM networks
if prefs.ExitNodeAllowLANAccess {
rs.LocalRoutes = append(rs.LocalRoutes, externalIPs...)
if len(externalIPs) != 0 {
b.logf("allowing exit node access to internal IPs: %v", internalIPs)
}
} else {
// Explicitly add routes to the local network so that we do not
// leak any traffic.
rs.Routes = append(rs.Routes, externalIPs...)
}
}
}
if tsaddr.PrefixesContainsFunc(rs.LocalAddrs, tsaddr.PrefixIs4) {
rs.Routes = append(rs.Routes, netaddr.IPPrefixFrom(tsaddr.TailscaleServiceIP(), 32))
}
return rs
}
func unmapIPPrefix(ipp netaddr.IPPrefix) netaddr.IPPrefix {
return netaddr.IPPrefixFrom(ipp.IP().Unmap(), ipp.Bits())
}
func unmapIPPrefixes(ippsList ...[]netaddr.IPPrefix) (ret []netaddr.IPPrefix) {
for _, ipps := range ippsList {
for _, ipp := range ipps {
ret = append(ret, unmapIPPrefix(ipp))
}
}
return ret
}
func applyPrefsToHostinfo(hi *tailcfg.Hostinfo, prefs *ipn.Prefs) {
if h := prefs.Hostname; h != "" {
hi.Hostname = h
}
hi.RoutableIPs = append(prefs.AdvertiseRoutes[:0:0], prefs.AdvertiseRoutes...)
hi.RequestTags = append(prefs.AdvertiseTags[:0:0], prefs.AdvertiseTags...)
hi.ShieldsUp = prefs.ShieldsUp
}
// enterState transitions the backend into newState, updating internal
// state and propagating events out as needed.
//
// TODO(danderson): while this isn't a lie, exactly, a ton of other
// places twiddle IPN internal state without going through here, so
// really this is more "one of several places in which random things
// happen".
func (b *LocalBackend) enterState(newState ipn.State) {
b.mu.Lock()
oldState := b.state
b.state = newState
prefs := b.prefs
netMap := b.netMap
activeLogin := b.activeLogin
authURL := b.authURL
if newState == ipn.Running {
b.authURL = ""
b.authURLSticky = ""
} else if oldState == ipn.Running {
// Transitioning away from running.
b.closePeerAPIListenersLocked()
}
b.maybePauseControlClientLocked()
b.mu.Unlock()
if oldState == newState {
return
}
b.logf("Switching ipn state %v -> %v (WantRunning=%v, nm=%v)",
oldState, newState, prefs.WantRunning, netMap != nil)
health.SetIPNState(newState.String(), prefs.WantRunning)
b.send(ipn.Notify{State: &newState})
switch newState {
case ipn.NeedsLogin:
systemd.Status("Needs login: %s", authURL)
b.blockEngineUpdates(true)
fallthrough
case ipn.Stopped:
err := b.e.Reconfig(&wgcfg.Config{}, &router.Config{}, &dns.Config{}, nil)
if err != nil {
b.logf("Reconfig(down): %v", err)
}
if authURL == "" {
systemd.Status("Stopped; run 'tailscale up' to log in")
}
case ipn.Starting, ipn.NeedsMachineAuth:
b.authReconfig()
// Needed so that UpdateEndpoints can run
b.e.RequestStatus()
case ipn.Running:
var addrs []string
for _, addr := range netMap.Addresses {
addrs = append(addrs, addr.IP().String())
}
systemd.Status("Connected; %s; %s", activeLogin, strings.Join(addrs, " "))
default:
b.logf("[unexpected] unknown newState %#v", newState)
}
}
func (b *LocalBackend) hasNodeKey() bool {
// we can't use b.Prefs(), because it strips the keys, oops!
b.mu.Lock()
p := b.prefs
b.mu.Unlock()
return p.Persist != nil && !p.Persist.PrivateNodeKey.IsZero()
}
// nextState returns the state the backend seems to be in, based on
// its internal state.
func (b *LocalBackend) nextState() ipn.State {
b.mu.Lock()
b.assertClientLocked()
var (
cc = b.cc
netMap = b.netMap
state = b.state
blocked = b.blocked
wantRunning = b.prefs.WantRunning
loggedOut = b.prefs.LoggedOut
st = b.engineStatus
keyExpired = b.keyExpired
)
b.mu.Unlock()
switch {
case !wantRunning && !loggedOut && !blocked && b.hasNodeKey():
return ipn.Stopped
case netMap == nil:
if cc.AuthCantContinue() || loggedOut {
// Auth was interrupted or waiting for URL visit,
// so it won't proceed without human help.
return ipn.NeedsLogin
}
switch state {
case ipn.Stopped:
// If we were already in the Stopped state, then
// we can assume auth is in good shape (or we would
// have been in NeedsLogin), so transition to Starting
// right away.
return ipn.Starting
case ipn.NoState:
// Our first time connecting to control, and we
// don't know if we'll NeedsLogin or not yet.
// UIs should print "Loading..." in this state.
return ipn.NoState
case ipn.Starting, ipn.Running, ipn.NeedsLogin:
return state
default:
b.logf("unexpected no-netmap state transition for %v", state)
return state
}
case !wantRunning:
return ipn.Stopped
case keyExpired:
// NetMap must be non-nil for us to get here.
// The node key expired, need to relogin.
return ipn.NeedsLogin
case netMap.MachineStatus != tailcfg.MachineAuthorized:
// TODO(crawshaw): handle tailcfg.MachineInvalid
return ipn.NeedsMachineAuth
case state == ipn.NeedsMachineAuth:
// (if we get here, we know MachineAuthorized == true)
return ipn.Starting
case state == ipn.Starting:
if st.NumLive > 0 || st.LiveDERPs > 0 {
return ipn.Running
} else {
return state
}
case state == ipn.Running:
return ipn.Running
default:
return ipn.Starting
}
}
// RequestEngineStatus implements Backend.
func (b *LocalBackend) RequestEngineStatus() {
b.e.RequestStatus()
}
// stateMachine updates the state machine state based on other things
// that have happened. It is invoked from the various callbacks that
// feed events into LocalBackend.
//
// TODO(apenwarr): use a channel or something to prevent re-entrancy?
// Or maybe just call the state machine from fewer places.
func (b *LocalBackend) stateMachine() {
b.enterState(b.nextState())
}
// stopEngineAndWait deconfigures the local network data plane, and
// waits for it to deliver a status update before returning.
//
// TODO(danderson): this may be racy. We could unblock upon receiving
// a status update that predates the "I've shut down" update.
func (b *LocalBackend) stopEngineAndWait() {
b.logf("stopEngineAndWait...")
b.e.Reconfig(&wgcfg.Config{}, &router.Config{}, &dns.Config{}, nil)
b.requestEngineStatusAndWait()
b.logf("stopEngineAndWait: done.")
}
// Requests the wgengine status, and does not return until the status
// was delivered (to the usual callback).
func (b *LocalBackend) requestEngineStatusAndWait() {
b.logf("requestEngineStatusAndWait")
b.statusLock.Lock()
go b.e.RequestStatus()
b.logf("requestEngineStatusAndWait: waiting...")
b.statusChanged.Wait() // temporarily releases lock while waiting
b.logf("requestEngineStatusAndWait: got status update.")
b.statusLock.Unlock()
}
// ResetForClientDisconnect resets the backend for GUI clients running
// in interactive (non-headless) mode. This is currently used only by
// Windows. This causes all state to be cleared, lest an unrelated user
// connect to tailscaled next. But it does not trigger a logout; we
// don't want to the user to have to reauthenticate in the future
// when they restart the GUI.
func (b *LocalBackend) ResetForClientDisconnect() {
defer b.enterState(ipn.Stopped)
b.mu.Lock()
defer b.mu.Unlock()
b.logf("LocalBackend.ResetForClientDisconnect")
if b.cc != nil {
go b.cc.Shutdown()
b.cc = nil
}
b.stateKey = ""
b.userID = ""
b.setNetMapLocked(nil)
b.prefs = new(ipn.Prefs)
b.keyExpired = false
b.authURL = ""
b.authURLSticky = ""
b.activeLogin = ""
}
// Logout tells the controlclient that we want to log out, and
// transitions the local engine to the logged-out state without
// waiting for controlclient to be in that state.
func (b *LocalBackend) Logout() {
b.logout(context.Background(), false)
}
func (b *LocalBackend) LogoutSync(ctx context.Context) error {
return b.logout(ctx, true)
}
func (b *LocalBackend) logout(ctx context.Context, sync bool) error {
b.mu.Lock()
cc := b.cc
b.mu.Unlock()
b.EditPrefs(&ipn.MaskedPrefs{
WantRunningSet: true,
LoggedOutSet: true,
Prefs: ipn.Prefs{WantRunning: false, LoggedOut: true},
})
if cc == nil {
// Double Logout can happen via repeated IPN
// connections to ipnserver making it repeatedly
// transition from 1->0 total connections, which on
// Windows by default ("client mode") causes a Logout
// on the transition to zero.
// Previously this crashed when we asserted that c was non-nil
// here.
return errors.New("no controlclient")
}
var err error
if sync {
err = cc.Logout(ctx)
} else {
cc.StartLogout()
}
b.stateMachine()
return err
}
// assertClientLocked crashes if there is no controlclient in this backend.
func (b *LocalBackend) assertClientLocked() {
if b.cc == nil {
panic("LocalBackend.assertClient: b.cc == nil")
}
}
// setNetInfo sets b.hostinfo.NetInfo to ni, and passes ni along to the
// controlclient, if one exists.
func (b *LocalBackend) setNetInfo(ni *tailcfg.NetInfo) {
b.mu.Lock()
cc := b.cc
if b.hostinfo != nil {
b.hostinfo.NetInfo = ni.Clone()
}
b.mu.Unlock()
if cc == nil {
return
}
cc.SetNetInfo(ni)
}
func hasCapability(nm *netmap.NetworkMap, cap string) bool {
if nm != nil && nm.SelfNode != nil {
for _, c := range nm.SelfNode.Capabilities {
if c == cap {
return true
}
}
}
return false
}
func (b *LocalBackend) setNetMapLocked(nm *netmap.NetworkMap) {
b.dialer.SetNetMap(nm)
var login string
if nm != nil {
login = nm.UserProfiles[nm.User].LoginName
if login == "" {
login = "<missing-profile>"
}
}
b.netMap = nm
if login != b.activeLogin {
b.logf("active login: %v", login)
b.activeLogin = login
}
b.maybePauseControlClientLocked()
if nm != nil {
health.SetControlHealth(nm.ControlHealth)
} else {
health.SetControlHealth(nil)
}
// Determine if file sharing is enabled
fs := hasCapability(nm, tailcfg.CapabilityFileSharing)
if fs != b.capFileSharing {
osshare.SetFileSharingEnabled(fs, b.logf)
}
b.capFileSharing = fs
if nm == nil {
b.nodeByAddr = nil
return
}
// Update the nodeByAddr index.
if b.nodeByAddr == nil {
b.nodeByAddr = map[netaddr.IP]*tailcfg.Node{}
}
// First pass, mark everything unwanted.
for k := range b.nodeByAddr {
b.nodeByAddr[k] = nil
}
addNode := func(n *tailcfg.Node) {
for _, ipp := range n.Addresses {
if ipp.IsSingleIP() {
b.nodeByAddr[ipp.IP()] = n
}
}
}
if nm.SelfNode != nil {
addNode(nm.SelfNode)
}
for _, p := range nm.Peers {
addNode(p)
}
// Third pass, actually delete the unwanted items.
for k, v := range b.nodeByAddr {
if v == nil {
delete(b.nodeByAddr, k)
}
}
}
// OperatorUserID returns the current pref's OperatorUser's ID (in
// os/user.User.Uid string form), or the empty string if none.
func (b *LocalBackend) OperatorUserID() string {
b.mu.Lock()
if b.prefs == nil {
b.mu.Unlock()
return ""
}
opUserName := b.prefs.OperatorUser
b.mu.Unlock()
if opUserName == "" {
return ""
}
u, err := user.Lookup(opUserName)
if err != nil {
b.logf("error looking up operator %q uid: %v", opUserName, err)
return ""
}
return u.Uid
}
// TestOnlyPublicKeys returns the current machine and node public
// keys. Used in tests only to facilitate automated node authorization
// in the test harness.
func (b *LocalBackend) TestOnlyPublicKeys() (machineKey key.MachinePublic, nodeKey key.NodePublic) {
b.mu.Lock()
prefs := b.prefs
machinePrivKey := b.machinePrivKey
b.mu.Unlock()
if prefs == nil || machinePrivKey.IsZero() {
return
}
mk := machinePrivKey.Public()
nk := prefs.Persist.PrivateNodeKey.Public()
return mk, nk
}
func (b *LocalBackend) WaitingFiles() ([]apitype.WaitingFile, error) {
b.mu.Lock()
apiSrv := b.peerAPIServer
b.mu.Unlock()
return apiSrv.WaitingFiles()
}
func (b *LocalBackend) DeleteFile(name string) error {
b.mu.Lock()
apiSrv := b.peerAPIServer
b.mu.Unlock()
return apiSrv.DeleteFile(name)
}
func (b *LocalBackend) OpenFile(name string) (rc io.ReadCloser, size int64, err error) {
b.mu.Lock()
apiSrv := b.peerAPIServer
b.mu.Unlock()
return apiSrv.OpenFile(name)
}
// hasCapFileSharing reports whether the current node has the file
// sharing capability enabled.
func (b *LocalBackend) hasCapFileSharing() bool {
b.mu.Lock()
defer b.mu.Unlock()
return b.capFileSharing
}
// FileTargets lists nodes that the current node can send files to.
func (b *LocalBackend) FileTargets() ([]*apitype.FileTarget, error) {
var ret []*apitype.FileTarget
b.mu.Lock()
defer b.mu.Unlock()
nm := b.netMap
if b.state != ipn.Running || nm == nil {
return nil, errors.New("not connected")
}
if !b.capFileSharing {
return nil, errors.New("file sharing not enabled by Tailscale admin")
}
for _, p := range nm.Peers {
if p.User != nm.User {
continue
}
peerAPI := peerAPIBase(b.netMap, p)
if peerAPI == "" {
continue
}
ret = append(ret, &apitype.FileTarget{
Node: p,
PeerAPIURL: peerAPI,
})
}
// TODO: sort a different way than the netmap already is?
return ret, nil
}
// SetDNS adds a DNS record for the given domain name & TXT record
// value.
//
// It's meant for use with dns-01 ACME (LetsEncrypt) challenges.
//
// This is the low-level interface. Other layers will provide more
// friendly options to get HTTPS certs.
func (b *LocalBackend) SetDNS(ctx context.Context, name, value string) error {
req := &tailcfg.SetDNSRequest{
Version: 1,
Type: "TXT",
Name: name,
Value: value,
}
b.mu.Lock()
cc := b.cc
if prefs := b.prefs; prefs != nil {
req.NodeKey = prefs.Persist.PrivateNodeKey.Public()
}
b.mu.Unlock()
if cc == nil {
return errors.New("not connected")
}
if req.NodeKey.IsZero() {
return errors.New("no nodekey")
}
if name == "" {
return errors.New("missing 'name'")
}
if value == "" {
return errors.New("missing 'value'")
}
return cc.SetDNS(ctx, req)
}
func (b *LocalBackend) registerIncomingFile(inf *incomingFile, active bool) {
b.mu.Lock()
defer b.mu.Unlock()
if b.incomingFiles == nil {
b.incomingFiles = make(map[*incomingFile]bool)
}
if active {
b.incomingFiles[inf] = true
} else {
delete(b.incomingFiles, inf)
}
}
// peerAPIBase returns the "http://ip:port" URL base to reach peer's peerAPI.
// It returns the empty string if the peer doesn't support the peerapi
// or there's no matching address family based on the netmap's own addresses.
func peerAPIBase(nm *netmap.NetworkMap, peer *tailcfg.Node) string {
if nm == nil || peer == nil {
return ""
}
var have4, have6 bool
for _, a := range nm.Addresses {
if !a.IsSingleIP() {
continue
}
switch {
case a.IP().Is4():
have4 = true
case a.IP().Is6():
have6 = true
}
}
var p4, p6 uint16
for _, s := range peer.Hostinfo.Services {
switch s.Proto {
case tailcfg.PeerAPI4:
p4 = s.Port
case tailcfg.PeerAPI6:
p6 = s.Port
}
}
var ipp netaddr.IPPort
switch {
case have4 && p4 != 0:
ipp = netaddr.IPPortFrom(nodeIP(peer, netaddr.IP.Is4), p4)
case have6 && p6 != 0:
ipp = netaddr.IPPortFrom(nodeIP(peer, netaddr.IP.Is6), p6)
}
if ipp.IP().IsZero() {
return ""
}
return fmt.Sprintf("http://%v", ipp)
}
func nodeIP(n *tailcfg.Node, pred func(netaddr.IP) bool) netaddr.IP {
for _, a := range n.Addresses {
if a.IsSingleIP() && pred(a.IP()) {
return a.IP()
}
}
return netaddr.IP{}
}
func isBSD(s string) bool {
return s == "dragonfly" || s == "freebsd" || s == "netbsd" || s == "openbsd"
}
func (b *LocalBackend) CheckIPForwarding() error {
if wgengine.IsNetstackRouter(b.e) {
return nil
}
switch {
case isBSD(runtime.GOOS):
return fmt.Errorf("Subnet routing and exit nodes only work with additional manual configuration on %v, and is not currently officially supported.", runtime.GOOS)
case runtime.GOOS == "linux":
return checkIPForwardingLinux()
default:
// TODO: subnet routing and exit nodes probably don't work
// correctly on non-linux, non-netstack OSes either. Warn
// instead of being silent?
return nil
}
}
// checkIPForwardingLinux checks if IP forwarding is enabled correctly
// for subnet routing and exit node functionality. Returns an error
// describing configuration issues if the configuration is not
// definitely good.
func checkIPForwardingLinux() error {
const kbLink = "\nSee https://tailscale.com/kb/1104/enable-ip-forwarding/"
disabled, err := disabledSysctls("net.ipv4.ip_forward", "net.ipv6.conf.all.forwarding")
if err != nil {
return fmt.Errorf("Couldn't check system's IP forwarding configuration, subnet routing/exit nodes may not work: %w%s", err, kbLink)
}
if len(disabled) == 0 {
// IP forwarding is enabled systemwide, all is well.
return nil
}
// IP forwarding isn't enabled globally, but it might be enabled
// on a per-interface basis. Check if it's on for all interfaces,
// and warn appropriately if it's not.
ifaces, err := interfaces.GetList()
if err != nil {
return fmt.Errorf("Couldn't enumerate network interfaces, subnet routing/exit nodes may not work: %w%s", err, kbLink)
}
var (
warnings []string
anyEnabled bool
)
for _, iface := range ifaces {
if iface.Name == "lo" {
continue
}
disabled, err = disabledSysctls(fmt.Sprintf("net.ipv4.conf.%s.forwarding", iface.Name), fmt.Sprintf("net.ipv6.conf.%s.forwarding", iface.Name))
if err != nil {
return fmt.Errorf("Couldn't check system's IP forwarding configuration, subnet routing/exit nodes may not work: %w%s", err, kbLink)
}
if len(disabled) > 0 {
warnings = append(warnings, fmt.Sprintf("Traffic received on %s won't be forwarded (%s disabled)", iface.Name, strings.Join(disabled, ", ")))
} else {
anyEnabled = true
}
}
if !anyEnabled {
// IP forwarding is compeltely disabled, just say that rather
// than enumerate all the interfaces on the system.
return fmt.Errorf("IP forwarding is disabled, subnet routing/exit nodes will not work.%s", kbLink)
}
if len(warnings) > 0 {
// If partially enabled, enumerate the bits that won't work.
return fmt.Errorf("%s\nSubnet routes and exit nodes may not work correctly.%s", strings.Join(warnings, "\n"), kbLink)
}
return nil
}
// disabledSysctls checks if the given sysctl keys are off, according
// to strconv.ParseBool. Returns a list of keys that are disabled, or
// err if something went wrong which prevented the lookups from
// completing.
func disabledSysctls(sysctls ...string) (disabled []string, err error) {
for _, k := range sysctls {
// TODO: on linux, we can get at these values via /proc/sys,
// rather than fork subcommands that may not be installed.
bs, err := exec.Command("sysctl", "-n", k).Output()
if err != nil {
return nil, fmt.Errorf("couldn't check %s (%v)", k, err)
}
on, err := strconv.ParseBool(string(bytes.TrimSpace(bs)))
if err != nil {
return nil, fmt.Errorf("couldn't parse %s (%v)", k, err)
}
if !on {
disabled = append(disabled, k)
}
}
return disabled, nil
}
// DERPMap returns the current DERPMap in use, or nil if not connected.
func (b *LocalBackend) DERPMap() *tailcfg.DERPMap {
b.mu.Lock()
defer b.mu.Unlock()
if b.netMap == nil {
return nil
}
return b.netMap.DERPMap
}
// OfferingExitNode reports whether b is currently offering exit node
// access.
func (b *LocalBackend) OfferingExitNode() bool {
b.mu.Lock()
defer b.mu.Unlock()
if b.prefs == nil {
return false
}
var def4, def6 bool
for _, r := range b.prefs.AdvertiseRoutes {
if r.Bits() != 0 {
continue
}
if r.IP().Is4() {
def4 = true
} else if r.IP().Is6() {
def6 = true
}
}
return def4 && def6
}
// allowExitNodeDNSProxyToServeName reports whether the Exit Node DNS
// proxy is allowed to serve responses for the provided DNS name.
func (b *LocalBackend) allowExitNodeDNSProxyToServeName(name string) bool {
b.mu.Lock()
defer b.mu.Unlock()
nm := b.netMap
if nm == nil {
return false
}
name = strings.ToLower(name)
for _, bad := range nm.DNS.ExitNodeFilteredSet {
if bad == "" {
// Invalid, ignore.
continue
}
if bad[0] == '.' {
// Entries beginning with a dot are suffix matches.
if dnsname.HasSuffix(name, bad) {
return false
}
continue
}
// Otherwise entries are exact matches. They're
// guaranteed to be lowercase already.
if name == bad {
return false
}
}
return true
}
// exitNodeCanProxyDNS reports the DoH base URL ("http://foo/dns-query") without query parameters
// to exitNodeID's DoH service, if available.
//
// If exitNodeID is the zero valid, it returns "", false.
func exitNodeCanProxyDNS(nm *netmap.NetworkMap, exitNodeID tailcfg.StableNodeID) (dohURL string, ok bool) {
if exitNodeID.IsZero() {
return "", false
}
for _, p := range nm.Peers {
if p.StableID != exitNodeID {
continue
}
for _, s := range p.Hostinfo.Services {
if s.Proto == tailcfg.PeerAPIDNS && s.Port >= 1 {
return peerAPIBase(nm, p) + "/dns-query", true
}
}
}
return "", false
}
func (b *LocalBackend) DebugRebind() error {
mc, err := b.magicConn()
if err != nil {
return err
}
mc.Rebind()
return nil
}
func (b *LocalBackend) DebugReSTUN() error {
mc, err := b.magicConn()
if err != nil {
return err
}
mc.ReSTUN("explicit-debug")
return nil
}
func (b *LocalBackend) magicConn() (*magicsock.Conn, error) {
ig, ok := b.e.(wgengine.InternalsGetter)
if !ok {
return nil, errors.New("engine isn't InternalsGetter")
}
_, mc, ok := ig.GetInternals()
if !ok {
return nil, errors.New("failed to get internals")
}
return mc, nil
}