tailscale/control/controlclient/direct.go

1511 lines
45 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 controlclient
import (
"bytes"
"context"
"encoding/binary"
"encoding/json"
"errors"
"flag"
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"net/url"
"os"
"os/exec"
"reflect"
"runtime"
"strings"
"sync"
"sync/atomic"
"time"
"go4.org/mem"
"golang.org/x/sync/singleflight"
"inet.af/netaddr"
"tailscale.com/control/controlknobs"
"tailscale.com/envknob"
"tailscale.com/health"
"tailscale.com/hostinfo"
"tailscale.com/ipn/ipnstate"
"tailscale.com/log/logheap"
"tailscale.com/net/dnscache"
"tailscale.com/net/dnsfallback"
"tailscale.com/net/interfaces"
"tailscale.com/net/netns"
"tailscale.com/net/tlsdial"
"tailscale.com/net/tshttpproxy"
"tailscale.com/tailcfg"
"tailscale.com/types/key"
"tailscale.com/types/logger"
"tailscale.com/types/netmap"
"tailscale.com/types/opt"
"tailscale.com/types/persist"
"tailscale.com/util/clientmetric"
"tailscale.com/util/multierr"
"tailscale.com/util/systemd"
"tailscale.com/wgengine/monitor"
)
// Direct is the client that connects to a tailcontrol server for a node.
type Direct struct {
httpc *http.Client // HTTP client used to talk to tailcontrol
serverURL string // URL of the tailcontrol server
timeNow func() time.Time
lastPrintMap time.Time
newDecompressor func() (Decompressor, error)
keepAlive bool
logf logger.Logf
linkMon *monitor.Mon // or nil
discoPubKey key.DiscoPublic
getMachinePrivKey func() (key.MachinePrivate, error)
debugFlags []string
keepSharerAndUserSplit bool
skipIPForwardingCheck bool
pinger Pinger
mu sync.Mutex // mutex guards the following fields
serverKey key.MachinePublic // original ("legacy") nacl crypto_box-based public key
serverNoiseKey key.MachinePublic
sfGroup singleflight.Group // protects noiseClient creation.
noiseClient *noiseClient
persist persist.Persist
authKey string
tryingNewKey key.NodePrivate
expiry *time.Time
// hostinfo is mutated in-place while mu is held.
hostinfo *tailcfg.Hostinfo // always non-nil
endpoints []tailcfg.Endpoint
everEndpoints bool // whether we've ever had non-empty endpoints
localPort uint16 // or zero to mean auto
lastPingURL string // last PingRequest.URL received, for dup suppression
}
type Options struct {
Persist persist.Persist // initial persistent data
GetMachinePrivateKey func() (key.MachinePrivate, error) // returns the machine key to use
ServerURL string // URL of the tailcontrol server
AuthKey string // optional node auth key for auto registration
TimeNow func() time.Time // time.Now implementation used by Client
Hostinfo *tailcfg.Hostinfo // non-nil passes ownership, nil means to use default using os.Hostname, etc
DiscoPublicKey key.DiscoPublic
NewDecompressor func() (Decompressor, error)
KeepAlive bool
Logf logger.Logf
HTTPTestClient *http.Client // optional HTTP client to use (for tests only)
DebugFlags []string // debug settings to send to control
LinkMonitor *monitor.Mon // optional link monitor
// KeepSharerAndUserSplit controls whether the client
// understands Node.Sharer. If false, the Sharer is mapped to the User.
KeepSharerAndUserSplit bool
// SkipIPForwardingCheck declares that the host's IP
// forwarding works and should not be double-checked by the
// controlclient package.
SkipIPForwardingCheck bool
// Pinger optionally specifies the Pinger to use to satisfy
// MapResponse.PingRequest queries from the control plane.
// If nil, PingRequest queries are not answered.
Pinger Pinger
}
// Pinger is a subset of the wgengine.Engine interface, containing just the Ping method.
type Pinger interface {
// Ping is a request to start a discovery or TSMP ping with the peer handling
// the given IP and then call cb with its ping latency & method.
Ping(ip netaddr.IP, useTSMP bool, cb func(*ipnstate.PingResult))
}
type Decompressor interface {
DecodeAll(input, dst []byte) ([]byte, error)
Close()
}
// NewDirect returns a new Direct client.
func NewDirect(opts Options) (*Direct, error) {
if opts.ServerURL == "" {
return nil, errors.New("controlclient.New: no server URL specified")
}
if opts.GetMachinePrivateKey == nil {
return nil, errors.New("controlclient.New: no GetMachinePrivateKey specified")
}
opts.ServerURL = strings.TrimRight(opts.ServerURL, "/")
serverURL, err := url.Parse(opts.ServerURL)
if err != nil {
return nil, err
}
if opts.TimeNow == nil {
opts.TimeNow = time.Now
}
if opts.Logf == nil {
// TODO(apenwarr): remove this default and fail instead.
// TODO(bradfitz): ... but then it shouldn't be in Options.
opts.Logf = log.Printf
}
httpc := opts.HTTPTestClient
if httpc == nil && runtime.GOOS == "js" {
// In js/wasm, net/http.Transport (as of Go 1.18) will
// only use the browser's Fetch API if you're using
// the DefaultClient (or a client without dial hooks
// etc set).
httpc = http.DefaultClient
}
if httpc == nil {
dnsCache := &dnscache.Resolver{
Forward: dnscache.Get().Forward, // use default cache's forwarder
UseLastGood: true,
LookupIPFallback: dnsfallback.Lookup,
}
dialer := netns.NewDialer(opts.Logf)
tr := http.DefaultTransport.(*http.Transport).Clone()
tr.Proxy = tshttpproxy.ProxyFromEnvironment
tshttpproxy.SetTransportGetProxyConnectHeader(tr)
tr.TLSClientConfig = tlsdial.Config(serverURL.Hostname(), tr.TLSClientConfig)
tr.DialContext = dnscache.Dialer(dialer.DialContext, dnsCache)
tr.DialTLSContext = dnscache.TLSDialer(dialer.DialContext, dnsCache, tr.TLSClientConfig)
tr.ForceAttemptHTTP2 = true
// Disable implicit gzip compression; the various
// handlers (register, map, set-dns, etc) do their own
// zstd compression per naclbox.
tr.DisableCompression = true
httpc = &http.Client{Transport: tr}
}
c := &Direct{
httpc: httpc,
getMachinePrivKey: opts.GetMachinePrivateKey,
serverURL: opts.ServerURL,
timeNow: opts.TimeNow,
logf: opts.Logf,
newDecompressor: opts.NewDecompressor,
keepAlive: opts.KeepAlive,
persist: opts.Persist,
authKey: opts.AuthKey,
discoPubKey: opts.DiscoPublicKey,
debugFlags: opts.DebugFlags,
keepSharerAndUserSplit: opts.KeepSharerAndUserSplit,
linkMon: opts.LinkMonitor,
skipIPForwardingCheck: opts.SkipIPForwardingCheck,
pinger: opts.Pinger,
}
if opts.Hostinfo == nil {
c.SetHostinfo(hostinfo.New())
} else {
c.SetHostinfo(opts.Hostinfo)
}
return c, nil
}
// Close closes the underlying Noise connection(s).
func (c *Direct) Close() error {
c.mu.Lock()
defer c.mu.Unlock()
if c.noiseClient != nil {
if err := c.noiseClient.Close(); err != nil {
return err
}
}
c.noiseClient = nil
return nil
}
// SetHostinfo clones the provided Hostinfo and remembers it for the
// next update. It reports whether the Hostinfo has changed.
func (c *Direct) SetHostinfo(hi *tailcfg.Hostinfo) bool {
if hi == nil {
panic("nil Hostinfo")
}
c.mu.Lock()
defer c.mu.Unlock()
if hi.Equal(c.hostinfo) {
return false
}
c.hostinfo = hi.Clone()
j, _ := json.Marshal(c.hostinfo)
c.logf("[v1] HostInfo: %s", j)
return true
}
// SetNetInfo clones the provided NetInfo and remembers it for the
// next update. It reports whether the NetInfo has changed.
func (c *Direct) SetNetInfo(ni *tailcfg.NetInfo) bool {
if ni == nil {
panic("nil NetInfo")
}
c.mu.Lock()
defer c.mu.Unlock()
if c.hostinfo == nil {
c.logf("[unexpected] SetNetInfo called with no HostInfo; ignoring NetInfo update: %+v", ni)
return false
}
if reflect.DeepEqual(ni, c.hostinfo.NetInfo) {
return false
}
c.hostinfo.NetInfo = ni.Clone()
return true
}
func (c *Direct) GetPersist() persist.Persist {
c.mu.Lock()
defer c.mu.Unlock()
return c.persist
}
func (c *Direct) TryLogout(ctx context.Context) error {
c.logf("[v1] direct.TryLogout()")
mustRegen, newURL, err := c.doLogin(ctx, loginOpt{Logout: true})
c.logf("[v1] TryLogout control response: mustRegen=%v, newURL=%v, err=%v", mustRegen, newURL, err)
c.mu.Lock()
c.persist = persist.Persist{}
c.mu.Unlock()
return err
}
func (c *Direct) TryLogin(ctx context.Context, t *tailcfg.Oauth2Token, flags LoginFlags) (url string, err error) {
c.logf("[v1] direct.TryLogin(token=%v, flags=%v)", t != nil, flags)
return c.doLoginOrRegen(ctx, loginOpt{Token: t, Flags: flags})
}
// WaitLoginURL sits in a long poll waiting for the user to authenticate at url.
//
// On success, newURL and err will both be nil.
func (c *Direct) WaitLoginURL(ctx context.Context, url string) (newURL string, err error) {
c.logf("[v1] direct.WaitLoginURL")
return c.doLoginOrRegen(ctx, loginOpt{URL: url})
}
func (c *Direct) doLoginOrRegen(ctx context.Context, opt loginOpt) (newURL string, err error) {
mustRegen, url, err := c.doLogin(ctx, opt)
if err != nil {
return url, err
}
if mustRegen {
opt.Regen = true
_, url, err = c.doLogin(ctx, opt)
}
return url, err
}
// SetExpirySooner attempts to shorten the expiry to the specified time.
func (c *Direct) SetExpirySooner(ctx context.Context, expiry time.Time) error {
c.logf("[v1] direct.SetExpirySooner()")
newURL, err := c.doLoginOrRegen(ctx, loginOpt{Expiry: &expiry})
c.logf("[v1] SetExpirySooner control response: newURL=%v, err=%v", newURL, err)
return err
}
type loginOpt struct {
Token *tailcfg.Oauth2Token
Flags LoginFlags
Regen bool // generate a new nodekey, can be overridden in doLogin
URL string
Logout bool // set the expiry to the far past, expiring the node
// Expiry, if non-nil, attempts to set the node expiry to the
// specified time and cannot be used to extend the expiry.
// It is ignored if Logout is set since Logout works by setting a
// expiry time in the far past.
Expiry *time.Time
}
// httpClient provides a common interface for the noiseClient and
// the NaCl box http.Client.
type httpClient interface {
Do(req *http.Request) (*http.Response, error)
}
func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, newURL string, err error) {
c.mu.Lock()
persist := c.persist
tryingNewKey := c.tryingNewKey
serverKey := c.serverKey
serverNoiseKey := c.serverNoiseKey
authKey := c.authKey
hi := c.hostinfo.Clone()
backendLogID := hi.BackendLogID
expired := c.expiry != nil && !c.expiry.IsZero() && c.expiry.Before(c.timeNow())
c.mu.Unlock()
machinePrivKey, err := c.getMachinePrivKey()
if err != nil {
return false, "", fmt.Errorf("getMachinePrivKey: %w", err)
}
if machinePrivKey.IsZero() {
return false, "", errors.New("getMachinePrivKey returned zero key")
}
regen := opt.Regen
if opt.Logout {
c.logf("logging out...")
} else {
if expired {
c.logf("Old key expired -> regen=true")
systemd.Status("key expired; run 'tailscale up' to authenticate")
regen = true
}
if (opt.Flags & LoginInteractive) != 0 {
c.logf("LoginInteractive -> regen=true")
regen = true
}
}
c.logf("doLogin(regen=%v, hasUrl=%v)", regen, opt.URL != "")
if serverKey.IsZero() {
keys, err := loadServerPubKeys(ctx, c.httpc, c.serverURL)
if err != nil {
return regen, opt.URL, err
}
c.logf("control server key %s from %s", serverKey.ShortString(), c.serverURL)
c.mu.Lock()
c.serverKey = keys.LegacyPublicKey
c.serverNoiseKey = keys.PublicKey
c.mu.Unlock()
serverKey = keys.LegacyPublicKey
serverNoiseKey = keys.PublicKey
// For servers supporting the Noise transport,
// proactively shut down our TLS TCP connection.
// We're not going to need it and it's nicer to the
// server.
if !serverNoiseKey.IsZero() {
c.httpc.CloseIdleConnections()
}
}
var oldNodeKey key.NodePublic
switch {
case opt.Logout:
tryingNewKey = persist.PrivateNodeKey
case opt.URL != "":
// Nothing.
case regen || persist.PrivateNodeKey.IsZero():
c.logf("Generating a new nodekey.")
persist.OldPrivateNodeKey = persist.PrivateNodeKey
tryingNewKey = key.NewNode()
default:
// Try refreshing the current key first
tryingNewKey = persist.PrivateNodeKey
}
if !persist.OldPrivateNodeKey.IsZero() {
oldNodeKey = persist.OldPrivateNodeKey.Public()
}
if tryingNewKey.IsZero() {
if opt.Logout {
return false, "", errors.New("no nodekey to log out")
}
log.Fatalf("tryingNewKey is empty, give up")
}
if backendLogID == "" {
err = errors.New("hostinfo: BackendLogID missing")
return regen, opt.URL, err
}
now := time.Now().Round(time.Second)
request := tailcfg.RegisterRequest{
Version: 1,
OldNodeKey: oldNodeKey,
NodeKey: tryingNewKey.Public(),
Hostinfo: hi,
Followup: opt.URL,
Timestamp: &now,
Ephemeral: (opt.Flags & LoginEphemeral) != 0,
}
if opt.Logout {
request.Expiry = time.Unix(123, 0) // far in the past
} else if opt.Expiry != nil {
request.Expiry = *opt.Expiry
}
c.logf("RegisterReq: onode=%v node=%v fup=%v",
request.OldNodeKey.ShortString(),
request.NodeKey.ShortString(), opt.URL != "")
request.Auth.Oauth2Token = opt.Token
request.Auth.Provider = persist.Provider
request.Auth.LoginName = persist.LoginName
request.Auth.AuthKey = authKey
err = signRegisterRequest(&request, c.serverURL, c.serverKey, machinePrivKey.Public())
if err != nil {
// If signing failed, clear all related fields
request.SignatureType = tailcfg.SignatureNone
request.Timestamp = nil
request.DeviceCert = nil
request.Signature = nil
// Don't log the common error types. Signatures are not usually enabled,
// so these are expected.
if !errors.Is(err, errCertificateNotConfigured) && !errors.Is(err, errNoCertStore) {
c.logf("RegisterReq sign error: %v", err)
}
}
if debugRegister {
j, _ := json.MarshalIndent(request, "", "\t")
c.logf("RegisterRequest: %s", j)
}
// URL and httpc are protocol specific.
var url string
var httpc httpClient
if serverNoiseKey.IsZero() {
httpc = c.httpc
url = fmt.Sprintf("%s/machine/%s", c.serverURL, machinePrivKey.Public().UntypedHexString())
} else {
request.Version = tailcfg.CurrentCapabilityVersion
httpc, err = c.getNoiseClient()
if err != nil {
return regen, opt.URL, fmt.Errorf("getNoiseClient: %w", err)
}
url = fmt.Sprintf("%s/machine/register", c.serverURL)
url = strings.Replace(url, "http:", "https:", 1)
}
bodyData, err := encode(request, serverKey, serverNoiseKey, machinePrivKey)
if err != nil {
return regen, opt.URL, err
}
req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(bodyData))
if err != nil {
return regen, opt.URL, err
}
res, err := httpc.Do(req)
if err != nil {
return regen, opt.URL, fmt.Errorf("register request: %w", err)
}
if res.StatusCode != 200 {
msg, _ := ioutil.ReadAll(res.Body)
res.Body.Close()
return regen, opt.URL, fmt.Errorf("register request: http %d: %.200s",
res.StatusCode, strings.TrimSpace(string(msg)))
}
resp := tailcfg.RegisterResponse{}
if err := decode(res, &resp, serverKey, serverNoiseKey, machinePrivKey); err != nil {
c.logf("error decoding RegisterResponse with server key %s and machine key %s: %v", serverKey, machinePrivKey.Public(), err)
return regen, opt.URL, fmt.Errorf("register request: %v", err)
}
if debugRegister {
j, _ := json.MarshalIndent(resp, "", "\t")
c.logf("RegisterResponse: %s", j)
}
// Log without PII:
c.logf("RegisterReq: got response; nodeKeyExpired=%v, machineAuthorized=%v; authURL=%v",
resp.NodeKeyExpired, resp.MachineAuthorized, resp.AuthURL != "")
if resp.Error != "" {
return false, "", UserVisibleError(resp.Error)
}
if resp.NodeKeyExpired {
if regen {
return true, "", fmt.Errorf("weird: regen=true but server says NodeKeyExpired: %v", request.NodeKey)
}
c.logf("server reports new node key %v has expired",
request.NodeKey.ShortString())
return true, "", nil
}
if resp.Login.Provider != "" {
persist.Provider = resp.Login.Provider
}
if resp.Login.LoginName != "" {
persist.LoginName = resp.Login.LoginName
}
// TODO(crawshaw): RegisterResponse should be able to mechanically
// communicate some extra instructions from the server:
// - new node key required
// - machine key no longer supported
// - user is disabled
if resp.AuthURL != "" {
c.logf("AuthURL is %v", resp.AuthURL)
} else {
c.logf("[v1] No AuthURL")
}
c.mu.Lock()
if resp.AuthURL == "" {
// key rotation is complete
persist.PrivateNodeKey = tryingNewKey
} else {
// save it for the retry-with-URL
c.tryingNewKey = tryingNewKey
}
c.persist = persist
c.mu.Unlock()
if err != nil {
return regen, "", err
}
if ctx.Err() != nil {
return regen, "", ctx.Err()
}
return false, resp.AuthURL, nil
}
func sameEndpoints(a, b []tailcfg.Endpoint) bool {
if len(a) != len(b) {
return false
}
for i := range a {
if a[i] != b[i] {
return false
}
}
return true
}
// newEndpoints acquires c.mu and sets the local port and endpoints and reports
// whether they've changed.
//
// It does not retain the provided slice.
func (c *Direct) newEndpoints(localPort uint16, endpoints []tailcfg.Endpoint) (changed bool) {
c.mu.Lock()
defer c.mu.Unlock()
// Nothing new?
if c.localPort == localPort && sameEndpoints(c.endpoints, endpoints) {
return false // unchanged
}
var epStrs []string
for _, ep := range endpoints {
epStrs = append(epStrs, ep.Addr.String())
}
c.logf("[v2] client.newEndpoints(%v, %v)", localPort, epStrs)
c.localPort = localPort
c.endpoints = append(c.endpoints[:0], endpoints...)
if len(endpoints) > 0 {
c.everEndpoints = true
}
return true // changed
}
// SetEndpoints updates the list of locally advertised endpoints.
// It won't be replicated to the server until a *fresh* call to PollNetMap().
// You don't need to restart PollNetMap if we return changed==false.
func (c *Direct) SetEndpoints(localPort uint16, endpoints []tailcfg.Endpoint) (changed bool) {
// (no log message on function entry, because it clutters the logs
// if endpoints haven't changed. newEndpoints() will log it.)
return c.newEndpoints(localPort, endpoints)
}
func inTest() bool { return flag.Lookup("test.v") != nil }
// PollNetMap makes a /map request to download the network map, calling cb with
// each new netmap.
//
// maxPolls is how many network maps to download; common values are 1
// or -1 (to keep a long-poll query open to the server).
func (c *Direct) PollNetMap(ctx context.Context, maxPolls int, cb func(*netmap.NetworkMap)) error {
return c.sendMapRequest(ctx, maxPolls, cb)
}
// SendLiteMapUpdate makes a /map request to update the server of our latest state,
// but does not fetch anything. It returns an error if the server did not return a
// successful 200 OK response.
func (c *Direct) SendLiteMapUpdate(ctx context.Context) error {
return c.sendMapRequest(ctx, 1, nil)
}
// If we go more than pollTimeout without hearing from the server,
// end the long poll. We should be receiving a keep alive ping
// every minute.
const pollTimeout = 120 * time.Second
// cb nil means to omit peers.
func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netmap.NetworkMap)) error {
metricMapRequests.Add(1)
metricMapRequestsActive.Add(1)
defer metricMapRequestsActive.Add(-1)
if maxPolls == -1 {
metricMapRequestsPoll.Add(1)
} else {
metricMapRequestsLite.Add(1)
}
c.mu.Lock()
persist := c.persist
serverURL := c.serverURL
serverKey := c.serverKey
serverNoiseKey := c.serverNoiseKey
hi := c.hostinfo.Clone()
backendLogID := hi.BackendLogID
localPort := c.localPort
var epStrs []string
var epTypes []tailcfg.EndpointType
for _, ep := range c.endpoints {
epStrs = append(epStrs, ep.Addr.String())
epTypes = append(epTypes, ep.Type)
}
everEndpoints := c.everEndpoints
c.mu.Unlock()
machinePrivKey, err := c.getMachinePrivKey()
if err != nil {
return fmt.Errorf("getMachinePrivKey: %w", err)
}
if machinePrivKey.IsZero() {
return errors.New("getMachinePrivKey returned zero key")
}
if persist.PrivateNodeKey.IsZero() {
return errors.New("privateNodeKey is zero")
}
if backendLogID == "" {
return errors.New("hostinfo: BackendLogID missing")
}
allowStream := maxPolls != 1
c.logf("[v1] PollNetMap: stream=%v :%v ep=%v", allowStream, localPort, epStrs)
vlogf := logger.Discard
if Debug.NetMap {
// TODO(bradfitz): update this to use "[v2]" prefix perhaps? but we don't
// want to upload it always.
vlogf = c.logf
}
request := &tailcfg.MapRequest{
Version: tailcfg.CurrentCapabilityVersion,
KeepAlive: c.keepAlive,
NodeKey: persist.PrivateNodeKey.Public(),
DiscoKey: c.discoPubKey,
Endpoints: epStrs,
EndpointTypes: epTypes,
Stream: allowStream,
Hostinfo: hi,
DebugFlags: c.debugFlags,
OmitPeers: cb == nil,
}
var extraDebugFlags []string
if hi != nil && c.linkMon != nil && !c.skipIPForwardingCheck &&
ipForwardingBroken(hi.RoutableIPs, c.linkMon.InterfaceState()) {
extraDebugFlags = append(extraDebugFlags, "warn-ip-forwarding-off")
}
if health.RouterHealth() != nil {
extraDebugFlags = append(extraDebugFlags, "warn-router-unhealthy")
}
if health.NetworkCategoryHealth() != nil {
extraDebugFlags = append(extraDebugFlags, "warn-network-category-unhealthy")
}
if hostinfo.DisabledEtcAptSource() {
extraDebugFlags = append(extraDebugFlags, "warn-etc-apt-source-disabled")
}
if len(extraDebugFlags) > 0 {
old := request.DebugFlags
request.DebugFlags = append(old[:len(old):len(old)], extraDebugFlags...)
}
if c.newDecompressor != nil {
request.Compress = "zstd"
}
// On initial startup before we know our endpoints, set the ReadOnly flag
// to tell the control server not to distribute out our (empty) endpoints to peers.
// Presumably we'll learn our endpoints in a half second and do another post
// with useful results. The first POST just gets us the DERP map which we
// need to do the STUN queries to discover our endpoints.
// TODO(bradfitz): we skip this optimization in tests, though,
// because the e2e tests are currently hyperspecific about the
// ordering of things. The e2e tests need love.
if len(epStrs) == 0 && !everEndpoints && !inTest() {
request.ReadOnly = true
}
bodyData, err := encode(request, serverKey, serverNoiseKey, machinePrivKey)
if err != nil {
vlogf("netmap: encode: %v", err)
return err
}
ctx, cancel := context.WithCancel(ctx)
defer cancel()
machinePubKey := machinePrivKey.Public()
t0 := time.Now()
// Url and httpc are protocol specific.
var url string
var httpc httpClient
if serverNoiseKey.IsZero() {
httpc = c.httpc
url = fmt.Sprintf("%s/machine/%s/map", serverURL, machinePubKey.UntypedHexString())
} else {
httpc, err = c.getNoiseClient()
if err != nil {
return fmt.Errorf("getNoiseClient: %w", err)
}
url = fmt.Sprintf("%s/machine/map", serverURL)
url = strings.Replace(url, "http:", "https:", 1)
}
req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(bodyData))
if err != nil {
return err
}
res, err := httpc.Do(req)
if err != nil {
vlogf("netmap: Do: %v", err)
return err
}
vlogf("netmap: Do = %v after %v", res.StatusCode, time.Since(t0).Round(time.Millisecond))
if res.StatusCode != 200 {
msg, _ := ioutil.ReadAll(res.Body)
res.Body.Close()
return fmt.Errorf("initial fetch failed %d: %.200s",
res.StatusCode, strings.TrimSpace(string(msg)))
}
defer res.Body.Close()
health.NoteMapRequestHeard(request)
if cb == nil {
io.Copy(ioutil.Discard, res.Body)
return nil
}
timeout := time.NewTimer(pollTimeout)
timeoutReset := make(chan struct{})
pollDone := make(chan struct{})
defer close(pollDone)
go func() {
for {
select {
case <-pollDone:
vlogf("netmap: ending timeout goroutine")
return
case <-timeout.C:
c.logf("map response long-poll timed out!")
cancel()
return
case <-timeoutReset:
if !timeout.Stop() {
select {
case <-timeout.C:
case <-pollDone:
vlogf("netmap: ending timeout goroutine")
return
}
}
vlogf("netmap: reset timeout timer")
timeout.Reset(pollTimeout)
}
}
}()
sess := newMapSession(persist.PrivateNodeKey)
sess.logf = c.logf
sess.vlogf = vlogf
sess.machinePubKey = machinePubKey
sess.keepSharerAndUserSplit = c.keepSharerAndUserSplit
// If allowStream, then the server will use an HTTP long poll to
// return incremental results. There is always one response right
// away, followed by a delay, and eventually others.
// If !allowStream, it'll still send the first result in exactly
// the same format before just closing the connection.
// We can use this same read loop either way.
var msg []byte
for i := 0; i < maxPolls || maxPolls < 0; i++ {
vlogf("netmap: starting size read after %v (poll %v)", time.Since(t0).Round(time.Millisecond), i)
var siz [4]byte
if _, err := io.ReadFull(res.Body, siz[:]); err != nil {
vlogf("netmap: size read error after %v: %v", time.Since(t0).Round(time.Millisecond), err)
return err
}
size := binary.LittleEndian.Uint32(siz[:])
vlogf("netmap: read size %v after %v", size, time.Since(t0).Round(time.Millisecond))
msg = append(msg[:0], make([]byte, size)...)
if _, err := io.ReadFull(res.Body, msg); err != nil {
vlogf("netmap: body read error: %v", err)
return err
}
vlogf("netmap: read body after %v", time.Since(t0).Round(time.Millisecond))
var resp tailcfg.MapResponse
if err := c.decodeMsg(msg, &resp, machinePrivKey); err != nil {
vlogf("netmap: decode error: %v")
return err
}
metricMapResponseMessages.Add(1)
if allowStream {
health.GotStreamedMapResponse()
}
if pr := resp.PingRequest; pr != nil && c.isUniquePingRequest(pr) {
metricMapResponsePings.Add(1)
go answerPing(c.logf, c.httpc, pr)
}
if resp.ControlTime != nil && !resp.ControlTime.IsZero() {
c.logf.JSON(1, "controltime", resp.ControlTime.UTC())
}
if resp.KeepAlive {
vlogf("netmap: got keep-alive")
} else {
vlogf("netmap: got new map")
}
select {
case timeoutReset <- struct{}{}:
vlogf("netmap: sent timer reset")
case <-ctx.Done():
c.logf("[v1] netmap: not resetting timer; context done: %v", ctx.Err())
return ctx.Err()
}
if resp.KeepAlive {
metricMapResponseKeepAlives.Add(1)
continue
}
metricMapResponseMap.Add(1)
if i > 0 {
metricMapResponseMapDelta.Add(1)
}
hasDebug := resp.Debug != nil
// being conservative here, if Debug not present set to False
controlknobs.SetDisableUPnP(hasDebug && resp.Debug.DisableUPnP.EqualBool(true))
if hasDebug {
if code := resp.Debug.Exit; code != nil {
c.logf("exiting process with status %v per controlplane", *code)
os.Exit(*code)
}
if resp.Debug.LogHeapPprof {
go logheap.LogHeap(resp.Debug.LogHeapURL)
}
if resp.Debug.GoroutineDumpURL != "" {
go dumpGoroutinesToURL(c.httpc, resp.Debug.GoroutineDumpURL)
}
setControlAtomic(&controlUseDERPRoute, resp.Debug.DERPRoute)
setControlAtomic(&controlTrimWGConfig, resp.Debug.TrimWGConfig)
if sleep := time.Duration(resp.Debug.SleepSeconds * float64(time.Second)); sleep > 0 {
if err := sleepAsRequested(ctx, c.logf, timeoutReset, sleep); err != nil {
return err
}
}
}
nm := sess.netmapForResponse(&resp)
if nm.SelfNode == nil {
c.logf("MapResponse lacked node")
return errors.New("MapResponse lacked node")
}
if Debug.StripEndpoints {
for _, p := range resp.Peers {
p.Endpoints = nil
}
}
if Debug.StripCaps {
nm.SelfNode.Capabilities = nil
}
// Get latest localPort. This might've changed if
// a lite map update occurred meanwhile. This only affects
// the end-to-end test.
// TODO(bradfitz): remove the NetworkMap.LocalPort field entirely.
c.mu.Lock()
nm.LocalPort = c.localPort
c.mu.Unlock()
// Occasionally print the netmap header.
// This is handy for debugging, and our logs processing
// pipeline depends on it. (TODO: Remove this dependency.)
// Code elsewhere prints netmap diffs every time they are received.
now := c.timeNow()
if now.Sub(c.lastPrintMap) >= 5*time.Minute {
c.lastPrintMap = now
c.logf("[v1] new network map[%d]:\n%s", i, nm.VeryConcise())
}
c.mu.Lock()
c.expiry = &nm.Expiry
c.mu.Unlock()
cb(nm)
}
if ctx.Err() != nil {
return ctx.Err()
}
return nil
}
// decode JSON decodes the res.Body into v. If serverNoiseKey is not specified,
// it uses the serverKey and mkey to decode the message from the NaCl-crypto-box.
func decode(res *http.Response, v any, serverKey, serverNoiseKey key.MachinePublic, mkey key.MachinePrivate) error {
defer res.Body.Close()
msg, err := ioutil.ReadAll(io.LimitReader(res.Body, 1<<20))
if err != nil {
return err
}
if res.StatusCode != 200 {
return fmt.Errorf("%d: %v", res.StatusCode, string(msg))
}
if !serverNoiseKey.IsZero() {
return json.Unmarshal(msg, v)
}
return decodeMsg(msg, v, serverKey, mkey)
}
var (
debugMap = envknob.Bool("TS_DEBUG_MAP")
debugRegister = envknob.Bool("TS_DEBUG_REGISTER")
)
var jsonEscapedZero = []byte(`\u0000`)
// decodeMsg is responsible for uncompressing msg and unmarshaling into v.
// If c.serverNoiseKey is not specified, it uses the c.serverKey and mkey
// to first the decrypt msg from the NaCl-crypto-box.
func (c *Direct) decodeMsg(msg []byte, v any, mkey key.MachinePrivate) error {
c.mu.Lock()
serverKey := c.serverKey
serverNoiseKey := c.serverNoiseKey
c.mu.Unlock()
var decrypted []byte
if serverNoiseKey.IsZero() {
var ok bool
decrypted, ok = mkey.OpenFrom(serverKey, msg)
if !ok {
return errors.New("cannot decrypt response")
}
} else {
decrypted = msg
}
var b []byte
if c.newDecompressor == nil {
b = decrypted
} else {
decoder, err := c.newDecompressor()
if err != nil {
return err
}
defer decoder.Close()
b, err = decoder.DecodeAll(decrypted, nil)
if err != nil {
return err
}
}
if debugMap {
var buf bytes.Buffer
json.Indent(&buf, b, "", " ")
log.Printf("MapResponse: %s", buf.Bytes())
}
if bytes.Contains(b, jsonEscapedZero) {
log.Printf("[unexpected] zero byte in controlclient.Direct.decodeMsg into %T: %q", v, b)
}
if err := json.Unmarshal(b, v); err != nil {
return fmt.Errorf("response: %v", err)
}
return nil
}
func decodeMsg(msg []byte, v any, serverKey key.MachinePublic, machinePrivKey key.MachinePrivate) error {
decrypted, ok := machinePrivKey.OpenFrom(serverKey, msg)
if !ok {
return errors.New("cannot decrypt response")
}
if bytes.Contains(decrypted, jsonEscapedZero) {
log.Printf("[unexpected] zero byte in controlclient decodeMsg into %T: %q", v, decrypted)
}
if err := json.Unmarshal(decrypted, v); err != nil {
return fmt.Errorf("response: %v", err)
}
return nil
}
// encode JSON encodes v. If serverNoiseKey is not specified, it uses the serverKey and mkey to
// seal the message into a NaCl-crypto-box.
func encode(v any, serverKey, serverNoiseKey key.MachinePublic, mkey key.MachinePrivate) ([]byte, error) {
b, err := json.Marshal(v)
if err != nil {
return nil, err
}
if debugMap {
if _, ok := v.(*tailcfg.MapRequest); ok {
log.Printf("MapRequest: %s", b)
}
}
if !serverNoiseKey.IsZero() {
return b, nil
}
return mkey.SealTo(serverKey, b), nil
}
func loadServerPubKeys(ctx context.Context, httpc *http.Client, serverURL string) (*tailcfg.OverTLSPublicKeyResponse, error) {
keyURL := fmt.Sprintf("%v/key?v=%d", serverURL, tailcfg.CurrentCapabilityVersion)
req, err := http.NewRequestWithContext(ctx, "GET", keyURL, nil)
if err != nil {
return nil, fmt.Errorf("create control key request: %v", err)
}
res, err := httpc.Do(req)
if err != nil {
return nil, fmt.Errorf("fetch control key: %v", err)
}
defer res.Body.Close()
b, err := ioutil.ReadAll(io.LimitReader(res.Body, 64<<10))
if err != nil {
return nil, fmt.Errorf("fetch control key response: %v", err)
}
if res.StatusCode != 200 {
return nil, fmt.Errorf("fetch control key: %d", res.StatusCode)
}
var out tailcfg.OverTLSPublicKeyResponse
jsonErr := json.Unmarshal(b, &out)
if jsonErr == nil {
return &out, nil
}
// Some old control servers might not be updated to send the new format.
// Accept the old pre-JSON format too.
out = tailcfg.OverTLSPublicKeyResponse{}
k, err := key.ParseMachinePublicUntyped(mem.B(b))
if err != nil {
return nil, multierr.New(jsonErr, err)
}
out.LegacyPublicKey = k
return &out, nil
}
// Debug contains temporary internal-only debug knobs.
// They're unexported to not draw attention to them.
var Debug = initDebug()
type debug struct {
NetMap bool
ProxyDNS bool
Disco bool
StripEndpoints bool // strip endpoints from control (only use disco messages)
StripCaps bool // strip all local node's control-provided capabilities
}
func initDebug() debug {
return debug{
NetMap: envknob.Bool("TS_DEBUG_NETMAP"),
ProxyDNS: envknob.Bool("TS_DEBUG_PROXY_DNS"),
StripEndpoints: envknob.Bool("TS_DEBUG_STRIP_ENDPOINTS"),
StripCaps: envknob.Bool("TS_DEBUG_STRIP_CAPS"),
Disco: envknob.BoolDefaultTrue("TS_DEBUG_USE_DISCO"),
}
}
var clockNow = time.Now
// opt.Bool configs from control.
var (
controlUseDERPRoute atomic.Value
controlTrimWGConfig atomic.Value
)
func setControlAtomic(dst *atomic.Value, v opt.Bool) {
old, ok := dst.Load().(opt.Bool)
if !ok || old != v {
dst.Store(v)
}
}
// DERPRouteFlag reports the last reported value from control for whether
// DERP route optimization (Issue 150) should be enabled.
func DERPRouteFlag() opt.Bool {
v, _ := controlUseDERPRoute.Load().(opt.Bool)
return v
}
// TrimWGConfig reports the last reported value from control for whether
// we should do lazy wireguard configuration.
func TrimWGConfig() opt.Bool {
v, _ := controlTrimWGConfig.Load().(opt.Bool)
return v
}
// ipForwardingBroken reports whether the system's IP forwarding is disabled
// and will definitely not work for the routes provided.
//
// It should not return false positives.
//
// TODO(bradfitz): merge this code into LocalBackend.CheckIPForwarding
// and change controlclient.Options.SkipIPForwardingCheck into a
// func([]netaddr.IPPrefix) error signature instead. Then we only have
// one copy of this code.
func ipForwardingBroken(routes []netaddr.IPPrefix, state *interfaces.State) bool {
if len(routes) == 0 {
// Nothing to route, so no need to warn.
return false
}
if runtime.GOOS != "linux" {
// We only do subnet routing on Linux for now.
// It might work on darwin/macOS when building from source, so
// don't return true for other OSes. We can OS-based warnings
// already in the admin panel.
return false
}
localIPs := map[netaddr.IP]bool{}
for _, addrs := range state.InterfaceIPs {
for _, pfx := range addrs {
localIPs[pfx.IP()] = true
}
}
v4Routes, v6Routes := false, false
for _, r := range routes {
// It's possible to advertise a route to one of the local
// machine's local IPs. IP forwarding isn't required for this
// to work, so we shouldn't warn for such exports.
if r.IsSingleIP() && localIPs[r.IP()] {
continue
}
if r.IP().Is4() {
v4Routes = true
} else {
v6Routes = true
}
}
if v4Routes {
out, err := ioutil.ReadFile("/proc/sys/net/ipv4/ip_forward")
if err != nil {
// Try another way.
out, err = exec.Command("sysctl", "-n", "net.ipv4.ip_forward").Output()
}
if err != nil {
// Oh well, we tried. This is just for debugging.
// We don't want false positives.
// TODO: maybe we want a different warning for inability to check?
return false
}
if strings.TrimSpace(string(out)) == "0" {
return true
}
}
if v6Routes {
// Note: you might be wondering why we check only the state of
// conf.all.forwarding, rather than per-interface forwarding
// configuration. According to kernel documentation, it seems
// that to actually forward packets, you need to enable
// forwarding globally, and the per-interface forwarding
// setting only alters other things such as how router
// advertisements are handled. The kernel itself warns that
// enabling forwarding per-interface and not globally will
// probably not work, so I feel okay calling those configs
// broken until we have proof otherwise.
out, err := ioutil.ReadFile("/proc/sys/net/ipv6/conf/all/forwarding")
if err != nil {
out, err = exec.Command("sysctl", "-n", "net.ipv6.conf.all.forwarding").Output()
}
if err != nil {
// Oh well, we tried. This is just for debugging.
// We don't want false positives.
// TODO: maybe we want a different warning for inability to check?
return false
}
if strings.TrimSpace(string(out)) == "0" {
return true
}
}
return false
}
// isUniquePingRequest reports whether pr contains a new PingRequest.URL
// not already handled, noting its value when returning true.
func (c *Direct) isUniquePingRequest(pr *tailcfg.PingRequest) bool {
if pr == nil || pr.URL == "" {
// Bogus.
return false
}
c.mu.Lock()
defer c.mu.Unlock()
if pr.URL == c.lastPingURL {
return false
}
c.lastPingURL = pr.URL
return true
}
func answerPing(logf logger.Logf, c *http.Client, pr *tailcfg.PingRequest) {
if pr.URL == "" {
logf("invalid PingRequest with no URL")
return
}
ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
defer cancel()
req, err := http.NewRequestWithContext(ctx, "HEAD", pr.URL, nil)
if err != nil {
logf("http.NewRequestWithContext(%q): %v", pr.URL, err)
return
}
if pr.Log {
logf("answerPing: sending ping to %v ...", pr.URL)
}
t0 := time.Now()
_, err = c.Do(req)
d := time.Since(t0).Round(time.Millisecond)
if err != nil {
logf("answerPing error: %v to %v (after %v)", err, pr.URL, d)
} else if pr.Log {
logf("answerPing complete to %v (after %v)", pr.URL, d)
}
}
func sleepAsRequested(ctx context.Context, logf logger.Logf, timeoutReset chan<- struct{}, d time.Duration) error {
const maxSleep = 5 * time.Minute
if d > maxSleep {
logf("sleeping for %v, capped from server-requested %v ...", maxSleep, d)
d = maxSleep
} else {
logf("sleeping for server-requested %v ...", d)
}
ticker := time.NewTicker(pollTimeout / 2)
defer ticker.Stop()
timer := time.NewTimer(d)
defer timer.Stop()
for {
select {
case <-ctx.Done():
return ctx.Err()
case <-timer.C:
return nil
case <-ticker.C:
select {
case timeoutReset <- struct{}{}:
case <-timer.C:
return nil
case <-ctx.Done():
return ctx.Err()
}
}
}
}
// getNoiseClient returns the noise client, creating one if one doesn't exist.
func (c *Direct) getNoiseClient() (*noiseClient, error) {
c.mu.Lock()
serverNoiseKey := c.serverNoiseKey
nc := c.noiseClient
c.mu.Unlock()
if serverNoiseKey.IsZero() {
return nil, errors.New("zero serverNoiseKey")
}
if nc != nil {
return nc, nil
}
np, err, _ := c.sfGroup.Do("noise", func() (any, error) {
k, err := c.getMachinePrivKey()
if err != nil {
return nil, err
}
nc, err = newNoiseClient(k, serverNoiseKey, c.serverURL)
if err != nil {
return nil, err
}
c.mu.Lock()
defer c.mu.Unlock()
c.noiseClient = nc
return nc, nil
})
if err != nil {
return nil, err
}
return np.(*noiseClient), nil
}
// setDNSNoise sends the SetDNSRequest request to the control plane server over Noise,
// requesting a DNS record be created or updated.
func (c *Direct) setDNSNoise(ctx context.Context, req *tailcfg.SetDNSRequest) error {
newReq := *req
newReq.Version = tailcfg.CurrentCapabilityVersion
np, err := c.getNoiseClient()
if err != nil {
return err
}
bodyData, err := json.Marshal(newReq)
if err != nil {
return err
}
res, err := np.Post(fmt.Sprintf("https://%v/%v", np.serverHost, "machine/set-dns"), "application/json", bytes.NewReader(bodyData))
if err != nil {
return err
}
defer res.Body.Close()
if res.StatusCode != 200 {
msg, _ := ioutil.ReadAll(res.Body)
return fmt.Errorf("set-dns response: %v, %.200s", res.Status, strings.TrimSpace(string(msg)))
}
var setDNSRes tailcfg.SetDNSResponse
if err := json.NewDecoder(res.Body).Decode(&setDNSRes); err != nil {
c.logf("error decoding SetDNSResponse: %v", err)
return fmt.Errorf("set-dns-response: %w", err)
}
return nil
}
// noiseConfigured reports whether the client can communicate with Control
// over Noise.
func (c *Direct) noiseConfigured() bool {
c.mu.Lock()
defer c.mu.Unlock()
return !c.serverNoiseKey.IsZero()
}
// SetDNS sends the SetDNSRequest request to the control plane server,
// requesting a DNS record be created or updated.
func (c *Direct) SetDNS(ctx context.Context, req *tailcfg.SetDNSRequest) (err error) {
metricSetDNS.Add(1)
defer func() {
if err != nil {
metricSetDNSError.Add(1)
}
}()
if c.noiseConfigured() {
return c.setDNSNoise(ctx, req)
}
c.mu.Lock()
serverKey := c.serverKey
c.mu.Unlock()
if serverKey.IsZero() {
return errors.New("zero serverKey")
}
machinePrivKey, err := c.getMachinePrivKey()
if err != nil {
return fmt.Errorf("getMachinePrivKey: %w", err)
}
if machinePrivKey.IsZero() {
return errors.New("getMachinePrivKey returned zero key")
}
// TODO(maisem): dedupe this codepath from SetDNSNoise.
var serverNoiseKey key.MachinePublic
bodyData, err := encode(req, serverKey, serverNoiseKey, machinePrivKey)
if err != nil {
return err
}
body := bytes.NewReader(bodyData)
u := fmt.Sprintf("%s/machine/%s/set-dns", c.serverURL, machinePrivKey.Public().UntypedHexString())
hreq, err := http.NewRequestWithContext(ctx, "POST", u, body)
if err != nil {
return err
}
res, err := c.httpc.Do(hreq)
if err != nil {
return err
}
defer res.Body.Close()
if res.StatusCode != 200 {
msg, _ := ioutil.ReadAll(res.Body)
return fmt.Errorf("set-dns response: %v, %.200s", res.Status, strings.TrimSpace(string(msg)))
}
var setDNSRes tailcfg.SetDNSResponse
if err := decode(res, &setDNSRes, serverKey, serverNoiseKey, machinePrivKey); err != nil {
c.logf("error decoding SetDNSResponse with server key %s and machine key %s: %v", serverKey, machinePrivKey.Public(), err)
return fmt.Errorf("set-dns-response: %w", err)
}
return nil
}
func (c *Direct) DoNoiseRequest(req *http.Request) (*http.Response, error) {
nc, err := c.getNoiseClient()
if err != nil {
return nil, err
}
return nc.Do(req)
}
// tsmpPing sends a Ping to pr.IP, and sends an http request back to pr.URL
// with ping response data.
func tsmpPing(logf logger.Logf, c *http.Client, pr *tailcfg.PingRequest, pinger Pinger) error {
var err error
if pr.URL == "" {
return errors.New("invalid PingRequest with no URL")
}
if pr.IP.IsZero() {
return errors.New("PingRequest without IP")
}
if !strings.Contains(pr.Types, "TSMP") {
return fmt.Errorf("PingRequest with no TSMP in Types, got %q", pr.Types)
}
now := time.Now()
pinger.Ping(pr.IP, true, func(res *ipnstate.PingResult) {
// Currently does not check for error since we just return if it fails.
err = postPingResult(now, logf, c, pr, res)
})
return err
}
func postPingResult(now time.Time, logf logger.Logf, c *http.Client, pr *tailcfg.PingRequest, res *ipnstate.PingResult) error {
if res.Err != "" {
return errors.New(res.Err)
}
duration := time.Since(now)
if pr.Log {
logf("TSMP ping to %v completed in %v seconds. pinger.Ping took %v seconds", pr.IP, res.LatencySeconds, duration.Seconds())
}
ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
defer cancel()
jsonPingRes, err := json.Marshal(res)
if err != nil {
return err
}
// Send the results of the Ping, back to control URL.
req, err := http.NewRequestWithContext(ctx, "POST", pr.URL, bytes.NewBuffer(jsonPingRes))
if err != nil {
return fmt.Errorf("http.NewRequestWithContext(%q): %w", pr.URL, err)
}
if pr.Log {
logf("tsmpPing: sending ping results to %v ...", pr.URL)
}
t0 := time.Now()
_, err = c.Do(req)
d := time.Since(t0).Round(time.Millisecond)
if err != nil {
return fmt.Errorf("tsmpPing error: %w to %v (after %v)", err, pr.URL, d)
} else if pr.Log {
logf("tsmpPing complete to %v (after %v)", pr.URL, d)
}
return nil
}
var (
metricMapRequestsActive = clientmetric.NewGauge("controlclient_map_requests_active")
metricMapRequests = clientmetric.NewCounter("controlclient_map_requests")
metricMapRequestsLite = clientmetric.NewCounter("controlclient_map_requests_lite")
metricMapRequestsPoll = clientmetric.NewCounter("controlclient_map_requests_poll")
metricMapResponseMessages = clientmetric.NewCounter("controlclient_map_response_message") // any message type
metricMapResponsePings = clientmetric.NewCounter("controlclient_map_response_ping")
metricMapResponseKeepAlives = clientmetric.NewCounter("controlclient_map_response_keepalive")
metricMapResponseMap = clientmetric.NewCounter("controlclient_map_response_map") // any non-keepalive map response
metricMapResponseMapDelta = clientmetric.NewCounter("controlclient_map_response_map_delta") // 2nd+ non-keepalive map response
metricSetDNS = clientmetric.NewCounter("controlclient_setdns")
metricSetDNSError = clientmetric.NewCounter("controlclient_setdns_error")
)