tailscale/control/controlclient/direct.go
Brad Fitzpatrick a2d78b4d3e net/dnscache, control/controlclient: use DNS cache when dialing control
Cache DNS results of earlier login.tailscale.com control dials, and use
them for future dials if DNS is slow or broken.

Fixes various issues with trickier setups with the domain's DNS server
behind a subnet router.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2020-11-11 12:50:04 -08:00

1100 lines
30 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
//go:generate go run tailscale.com/cmd/cloner -type=Persist -output=direct_clone.go
import (
"bytes"
"context"
"crypto/rand"
"encoding/binary"
"encoding/json"
"errors"
"flag"
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"net/url"
"os"
"os/exec"
"reflect"
"runtime"
"sort"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/tailscale/wireguard-go/wgcfg"
"golang.org/x/crypto/nacl/box"
"golang.org/x/oauth2"
"inet.af/netaddr"
"tailscale.com/log/logheap"
"tailscale.com/net/dnscache"
"tailscale.com/net/netns"
"tailscale.com/net/tlsdial"
"tailscale.com/net/tshttpproxy"
"tailscale.com/tailcfg"
"tailscale.com/types/logger"
"tailscale.com/types/opt"
"tailscale.com/types/structs"
"tailscale.com/version"
)
type Persist struct {
_ structs.Incomparable
// LegacyFrontendPrivateMachineKey is here temporarily
// (starting 2020-09-28) during migration of Windows users'
// machine keys from frontend storage to the backend. On the
// first LocalBackend.Start call, the backend will initialize
// the real (backend-owned) machine key from the frontend's
// provided value (if non-zero), picking a new random one if
// needed. This field should be considered read-only from GUI
// frontends. The real value should not be written back in
// this field, lest the frontend persist it to disk.
LegacyFrontendPrivateMachineKey wgcfg.PrivateKey `json:"PrivateMachineKey"`
PrivateNodeKey wgcfg.PrivateKey
OldPrivateNodeKey wgcfg.PrivateKey // needed to request key rotation
Provider string
LoginName string
}
func (p *Persist) Equals(p2 *Persist) bool {
if p == nil && p2 == nil {
return true
}
if p == nil || p2 == nil {
return false
}
return p.LegacyFrontendPrivateMachineKey.Equal(p2.LegacyFrontendPrivateMachineKey) &&
p.PrivateNodeKey.Equal(p2.PrivateNodeKey) &&
p.OldPrivateNodeKey.Equal(p2.OldPrivateNodeKey) &&
p.Provider == p2.Provider &&
p.LoginName == p2.LoginName
}
func (p *Persist) Pretty() string {
var mk, ok, nk wgcfg.Key
if !p.LegacyFrontendPrivateMachineKey.IsZero() {
mk = p.LegacyFrontendPrivateMachineKey.Public()
}
if !p.OldPrivateNodeKey.IsZero() {
ok = p.OldPrivateNodeKey.Public()
}
if !p.PrivateNodeKey.IsZero() {
nk = p.PrivateNodeKey.Public()
}
ss := func(k wgcfg.Key) string {
if k.IsZero() {
return ""
}
return k.ShortString()
}
return fmt.Sprintf("Persist{lm=%v, o=%v, n=%v u=%#v}",
ss(mk), ss(ok), ss(nk), p.LoginName)
}
// 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
discoPubKey tailcfg.DiscoKey
machinePrivKey wgcfg.PrivateKey
debugFlags []string
mu sync.Mutex // mutex guards the following fields
serverKey wgcfg.Key
persist Persist
authKey string
tryingNewKey wgcfg.PrivateKey
expiry *time.Time
// hostinfo is mutated in-place while mu is held.
hostinfo *tailcfg.Hostinfo // always non-nil
endpoints []string
everEndpoints bool // whether we've ever had non-empty endpoints
localPort uint16 // or zero to mean auto
}
type Options struct {
Persist Persist // initial persistent data
MachinePrivateKey wgcfg.PrivateKey // 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 tailcfg.DiscoKey
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
}
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.MachinePrivateKey.IsZero() {
return nil, errors.New("controlclient.New: no MachinePrivateKey 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 {
dnsCache := &dnscache.Resolver{
Forward: dnscache.Get().Forward, // use default cache's forwarder
UseLastGood: true,
}
dialer := netns.NewDialer()
tr := http.DefaultTransport.(*http.Transport).Clone()
tr.Proxy = tshttpproxy.ProxyFromEnvironment
tshttpproxy.SetTransportGetProxyConnectHeader(tr)
tr.DialContext = dnscache.Dialer(dialer.DialContext, dnsCache)
tr.ForceAttemptHTTP2 = true
tr.TLSClientConfig = tlsdial.Config(serverURL.Host, tr.TLSClientConfig)
httpc = &http.Client{Transport: tr}
}
c := &Direct{
httpc: httpc,
machinePrivKey: opts.MachinePrivateKey,
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,
}
if opts.Hostinfo == nil {
c.SetHostinfo(NewHostinfo())
} else {
c.SetHostinfo(opts.Hostinfo)
}
return c, nil
}
var osVersion func() string // non-nil on some platforms
func NewHostinfo() *tailcfg.Hostinfo {
hostname, _ := os.Hostname()
var osv string
if osVersion != nil {
osv = osVersion()
}
return &tailcfg.Hostinfo{
IPNVersion: version.Long,
Hostname: hostname,
OS: version.OS(),
OSVersion: osv,
GoArch: runtime.GOARCH,
}
}
// 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("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 {
c.mu.Lock()
defer c.mu.Unlock()
return c.persist
}
type LoginFlags int
const (
LoginDefault = LoginFlags(0)
LoginInteractive = LoginFlags(1 << iota) // force user login and key refresh
)
func (c *Direct) TryLogout(ctx context.Context) error {
c.logf("direct.TryLogout()")
c.mu.Lock()
defer c.mu.Unlock()
// TODO(crawshaw): Tell the server. This node key should be
// immediately invalidated.
//if !c.persist.PrivateNodeKey.IsZero() {
//}
c.persist = Persist{}
return nil
}
func (c *Direct) TryLogin(ctx context.Context, t *oauth2.Token, flags LoginFlags) (url string, err error) {
c.logf("direct.TryLogin(token=%v, flags=%v)", t != nil, flags)
return c.doLoginOrRegen(ctx, t, flags, false, "")
}
func (c *Direct) WaitLoginURL(ctx context.Context, url string) (newUrl string, err error) {
c.logf("direct.WaitLoginURL")
return c.doLoginOrRegen(ctx, nil, LoginDefault, false, url)
}
func (c *Direct) doLoginOrRegen(ctx context.Context, t *oauth2.Token, flags LoginFlags, regen bool, url string) (newUrl string, err error) {
mustregen, url, err := c.doLogin(ctx, t, flags, regen, url)
if err != nil {
return url, err
}
if mustregen {
_, url, err = c.doLogin(ctx, t, flags, true, url)
}
return url, err
}
func (c *Direct) doLogin(ctx context.Context, t *oauth2.Token, flags LoginFlags, regen bool, url string) (mustregen bool, newurl string, err error) {
c.mu.Lock()
persist := c.persist
tryingNewKey := c.tryingNewKey
serverKey := c.serverKey
authKey := c.authKey
hostinfo := c.hostinfo.Clone()
backendLogID := hostinfo.BackendLogID
expired := c.expiry != nil && !c.expiry.IsZero() && c.expiry.Before(c.timeNow())
c.mu.Unlock()
if c.machinePrivKey.IsZero() {
return false, "", errors.New("controlclient.Direct requires a machine private key")
}
if expired {
c.logf("Old key expired -> regen=true")
regen = true
}
if (flags & LoginInteractive) != 0 {
c.logf("LoginInteractive -> regen=true")
regen = true
}
c.logf("doLogin(regen=%v, hasUrl=%v)", regen, url != "")
if serverKey == (wgcfg.Key{}) {
var err error
serverKey, err = loadServerKey(ctx, c.httpc, c.serverURL)
if err != nil {
return regen, url, err
}
c.mu.Lock()
c.serverKey = serverKey
c.mu.Unlock()
}
var oldNodeKey wgcfg.Key
if url != "" {
} else if regen || persist.PrivateNodeKey.IsZero() {
c.logf("Generating a new nodekey.")
persist.OldPrivateNodeKey = persist.PrivateNodeKey
key, err := wgcfg.NewPrivateKey()
if err != nil {
c.logf("login keygen: %v", err)
return regen, url, err
}
tryingNewKey = key
} else {
// Try refreshing the current key first
tryingNewKey = persist.PrivateNodeKey
}
if !persist.OldPrivateNodeKey.IsZero() {
oldNodeKey = persist.OldPrivateNodeKey.Public()
}
if tryingNewKey.IsZero() {
log.Fatalf("tryingNewKey is empty, give up")
}
if backendLogID == "" {
err = errors.New("hostinfo: BackendLogID missing")
return regen, url, err
}
request := tailcfg.RegisterRequest{
Version: 1,
OldNodeKey: tailcfg.NodeKey(oldNodeKey),
NodeKey: tailcfg.NodeKey(tryingNewKey.Public()),
Hostinfo: hostinfo,
Followup: url,
}
c.logf("RegisterReq: onode=%v node=%v fup=%v",
request.OldNodeKey.ShortString(),
request.NodeKey.ShortString(), url != "")
request.Auth.Oauth2Token = t
request.Auth.Provider = persist.Provider
request.Auth.LoginName = persist.LoginName
request.Auth.AuthKey = authKey
bodyData, err := encode(request, &serverKey, &c.machinePrivKey)
if err != nil {
return regen, url, err
}
body := bytes.NewReader(bodyData)
u := fmt.Sprintf("%s/machine/%s", c.serverURL, c.machinePrivKey.Public().HexString())
req, err := http.NewRequest("POST", u, body)
if err != nil {
return regen, url, err
}
req = req.WithContext(ctx)
res, err := c.httpc.Do(req)
if err != nil {
return regen, url, fmt.Errorf("register request: %v", err)
}
if res.StatusCode != 200 {
msg, _ := ioutil.ReadAll(res.Body)
res.Body.Close()
return regen, url, fmt.Errorf("register request: http %d: %.200s",
res.StatusCode, strings.TrimSpace(string(msg)))
}
resp := tailcfg.RegisterResponse{}
if err := decode(res, &resp, &serverKey, &c.machinePrivKey); err != nil {
c.logf("error decoding RegisterResponse with server key %s and machine key %s: %v", serverKey, c.machinePrivKey.Public(), err)
return regen, url, fmt.Errorf("register request: %v", err)
}
// Log without PII:
c.logf("RegisterReq: got response; nodeKeyExpired=%v, machineAuthorized=%v; authURL=%v",
resp.NodeKeyExpired, resp.MachineAuthorized, resp.AuthURL != "")
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 persist.Provider == "" {
persist.Provider = resp.Login.Provider
}
if persist.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("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 sameStrings(a, b []string) 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 []string) (changed bool) {
c.mu.Lock()
defer c.mu.Unlock()
// Nothing new?
if c.localPort == localPort && sameStrings(c.endpoints, endpoints) {
return false // unchanged
}
c.logf("client.newEndpoints(%v, %v)", localPort, endpoints)
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 []string) (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(*NetworkMap)) error {
c.mu.Lock()
persist := c.persist
serverURL := c.serverURL
serverKey := c.serverKey
hostinfo := c.hostinfo.Clone()
backendLogID := hostinfo.BackendLogID
localPort := c.localPort
ep := append([]string(nil), c.endpoints...)
everEndpoints := c.everEndpoints
c.mu.Unlock()
if backendLogID == "" {
return errors.New("hostinfo: BackendLogID missing")
}
allowStream := maxPolls != 1
c.logf("PollNetMap: stream=%v :%v ep=%v", allowStream, localPort, ep)
vlogf := logger.Discard
if Debug.NetMap {
vlogf = c.logf
}
request := tailcfg.MapRequest{
Version: 5,
KeepAlive: c.keepAlive,
NodeKey: tailcfg.NodeKey(persist.PrivateNodeKey.Public()),
DiscoKey: c.discoPubKey,
Endpoints: ep,
Stream: allowStream,
Hostinfo: hostinfo,
DebugFlags: c.debugFlags,
}
if hostinfo != nil && ipForwardingBroken(hostinfo.RoutableIPs) {
old := request.DebugFlags
request.DebugFlags = append(old[:len(old):len(old)], "warn-ip-forwarding-off")
}
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(ep) == 0 && !everEndpoints && !inTest() {
request.ReadOnly = true
}
bodyData, err := encode(request, &serverKey, &c.machinePrivKey)
if err != nil {
vlogf("netmap: encode: %v", err)
return err
}
ctx, cancel := context.WithCancel(ctx)
defer cancel()
machinePubKey := tailcfg.MachineKey(c.machinePrivKey.Public())
t0 := time.Now()
u := fmt.Sprintf("%s/machine/%s/map", serverURL, machinePubKey.HexString())
req, err := http.NewRequestWithContext(ctx, "POST", u, bytes.NewReader(bodyData))
if err != nil {
return err
}
res, err := c.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()
// 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
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)
}
}
}()
var lastDERPMap *tailcfg.DERPMap
var lastUserProfile = map[tailcfg.UserID]tailcfg.UserProfile{}
// 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
var previousPeers []*tailcfg.Node // for delta-purposes
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); err != nil {
vlogf("netmap: decode error: %v")
return err
}
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("netmap: not resetting timer; context done: %v", ctx.Err())
return ctx.Err()
}
if resp.KeepAlive {
continue
}
undeltaPeers(&resp, previousPeers)
previousPeers = cloneNodes(resp.Peers) // defensive/lazy clone, since this escapes to who knows where
for _, up := range resp.UserProfiles {
lastUserProfile[up.ID] = up
}
if resp.DERPMap != nil {
vlogf("netmap: new map contains DERP map")
lastDERPMap = resp.DERPMap
}
if resp.Debug != nil {
if resp.Debug.LogHeapPprof {
go logheap.LogHeap(resp.Debug.LogHeapURL)
}
setControlAtomic(&controlUseDERPRoute, resp.Debug.DERPRoute)
setControlAtomic(&controlTrimWGConfig, resp.Debug.TrimWGConfig)
}
// Temporarily (2020-06-29) support removing all but
// discovery-supporting nodes during development, for
// less noise.
if Debug.OnlyDisco {
filtered := resp.Peers[:0]
for _, p := range resp.Peers {
if !p.DiscoKey.IsZero() {
filtered = append(filtered, p)
}
}
resp.Peers = filtered
}
nm := &NetworkMap{
NodeKey: tailcfg.NodeKey(persist.PrivateNodeKey.Public()),
PrivateKey: persist.PrivateNodeKey,
MachineKey: machinePubKey,
Expiry: resp.Node.KeyExpiry,
Name: resp.Node.Name,
Addresses: resp.Node.Addresses,
Peers: resp.Peers,
LocalPort: localPort,
User: resp.Node.User,
UserProfiles: make(map[tailcfg.UserID]tailcfg.UserProfile),
Domain: resp.Domain,
DNS: resp.DNSConfig,
Hostinfo: resp.Node.Hostinfo,
PacketFilter: c.parsePacketFilter(resp.PacketFilter),
DERPMap: lastDERPMap,
Debug: resp.Debug,
}
addUserProfile := func(userID tailcfg.UserID) {
if _, dup := nm.UserProfiles[userID]; dup {
// Already populated it from a previous peer.
return
}
if up, ok := lastUserProfile[userID]; ok {
nm.UserProfiles[userID] = up
}
}
addUserProfile(nm.User)
for _, peer := range resp.Peers {
addUserProfile(peer.User)
}
if resp.Node.MachineAuthorized {
nm.MachineStatus = tailcfg.MachineAuthorized
} else {
nm.MachineStatus = tailcfg.MachineUnauthorized
}
if len(resp.DNS) > 0 {
nm.DNS.Nameservers = wgIPToNetaddr(resp.DNS)
}
if len(resp.SearchPaths) > 0 {
nm.DNS.Domains = resp.SearchPaths
}
if Debug.ProxyDNS {
nm.DNS.Proxied = true
}
// Printing the netmap can be extremely verbose, but is very
// handy for debugging. Let's limit how often we do it.
// Code elsewhere prints netmap diffs every time, so this
// occasional full dump, plus incremental diffs, should do
// the job.
now := c.timeNow()
if now.Sub(c.lastPrintMap) >= 5*time.Minute {
c.lastPrintMap = now
c.logf("new network map[%d]:\n%s", i, nm.Concise())
}
c.mu.Lock()
c.expiry = &nm.Expiry
c.mu.Unlock()
cb(nm)
}
if ctx.Err() != nil {
return ctx.Err()
}
return nil
}
func decode(res *http.Response, v interface{}, serverKey *wgcfg.Key, mkey *wgcfg.PrivateKey) 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))
}
return decodeMsg(msg, v, serverKey, mkey)
}
var debugMap, _ = strconv.ParseBool(os.Getenv("TS_DEBUG_MAP"))
func (c *Direct) decodeMsg(msg []byte, v interface{}) error {
c.mu.Lock()
serverKey := c.serverKey
c.mu.Unlock()
decrypted, err := decryptMsg(msg, &serverKey, &c.machinePrivKey)
if err != nil {
return err
}
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 err := json.Unmarshal(b, v); err != nil {
return fmt.Errorf("response: %v", err)
}
return nil
}
func decodeMsg(msg []byte, v interface{}, serverKey *wgcfg.Key, mkey *wgcfg.PrivateKey) error {
decrypted, err := decryptMsg(msg, serverKey, mkey)
if err != nil {
return err
}
if err := json.Unmarshal(decrypted, v); err != nil {
return fmt.Errorf("response: %v", err)
}
return nil
}
func decryptMsg(msg []byte, serverKey *wgcfg.Key, mkey *wgcfg.PrivateKey) ([]byte, error) {
var nonce [24]byte
if len(msg) < len(nonce)+1 {
return nil, fmt.Errorf("response missing nonce, len=%d", len(msg))
}
copy(nonce[:], msg)
msg = msg[len(nonce):]
pub, pri := (*[32]byte)(serverKey), (*[32]byte)(mkey)
decrypted, ok := box.Open(nil, msg, &nonce, pub, pri)
if !ok {
return nil, fmt.Errorf("cannot decrypt response (len %d + nonce %d = %d)", len(msg), len(nonce), len(msg)+len(nonce))
}
return decrypted, nil
}
func encode(v interface{}, serverKey *wgcfg.Key, mkey *wgcfg.PrivateKey) ([]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)
}
}
var nonce [24]byte
if _, err := io.ReadFull(rand.Reader, nonce[:]); err != nil {
panic(err)
}
pub, pri := (*[32]byte)(serverKey), (*[32]byte)(mkey)
msg := box.Seal(nonce[:], b, &nonce, pub, pri)
return msg, nil
}
func loadServerKey(ctx context.Context, httpc *http.Client, serverURL string) (wgcfg.Key, error) {
req, err := http.NewRequest("GET", serverURL+"/key", nil)
if err != nil {
return wgcfg.Key{}, fmt.Errorf("create control key request: %v", err)
}
req = req.WithContext(ctx)
res, err := httpc.Do(req)
if err != nil {
return wgcfg.Key{}, fmt.Errorf("fetch control key: %v", err)
}
defer res.Body.Close()
b, err := ioutil.ReadAll(io.LimitReader(res.Body, 1<<16))
if err != nil {
return wgcfg.Key{}, fmt.Errorf("fetch control key response: %v", err)
}
if res.StatusCode != 200 {
return wgcfg.Key{}, fmt.Errorf("fetch control key: %d: %s", res.StatusCode, string(b))
}
key, err := wgcfg.ParseHexKey(string(b))
if err != nil {
return wgcfg.Key{}, fmt.Errorf("fetch control key: %v", err)
}
return key, nil
}
func wgIPToNetaddr(ips []wgcfg.IP) (ret []netaddr.IP) {
for _, ip := range ips {
nip, ok := netaddr.FromStdIP(ip.IP())
if !ok {
panic(fmt.Sprintf("conversion of %s from wgcfg to netaddr IP failed", ip))
}
ret = append(ret, nip.Unmap())
}
return ret
}
// 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
OnlyDisco bool
Disco bool
}
func initDebug() debug {
use := os.Getenv("TS_DEBUG_USE_DISCO")
return debug{
NetMap: envBool("TS_DEBUG_NETMAP"),
ProxyDNS: envBool("TS_DEBUG_PROXY_DNS"),
OnlyDisco: use == "only",
Disco: use == "only" || use == "" || envBool("TS_DEBUG_USE_DISCO"),
}
}
func envBool(k string) bool {
e := os.Getenv(k)
if e == "" {
return false
}
v, err := strconv.ParseBool(e)
if err != nil {
panic(fmt.Sprintf("invalid non-bool %q for env var %q", e, k))
}
return v
}
// undeltaPeers updates mapRes.Peers to be complete based on the provided previous peer list
// and the PeersRemoved and PeersChanged fields in mapRes.
// It then also nils out the delta fields.
func undeltaPeers(mapRes *tailcfg.MapResponse, prev []*tailcfg.Node) {
if len(mapRes.Peers) > 0 {
// Not delta encoded.
if !nodesSorted(mapRes.Peers) {
log.Printf("netmap: undeltaPeers: MapResponse.Peers not sorted; sorting")
sortNodes(mapRes.Peers)
}
return
}
var removed map[tailcfg.NodeID]bool
if pr := mapRes.PeersRemoved; len(pr) > 0 {
removed = make(map[tailcfg.NodeID]bool, len(pr))
for _, id := range pr {
removed[id] = true
}
}
changed := mapRes.PeersChanged
if len(removed) == 0 && len(changed) == 0 {
// No changes fast path.
mapRes.Peers = prev
return
}
if !nodesSorted(changed) {
log.Printf("netmap: undeltaPeers: MapResponse.PeersChanged not sorted; sorting")
sortNodes(changed)
}
if !nodesSorted(prev) {
// Internal error (unrelated to the network) if we get here.
log.Printf("netmap: undeltaPeers: [unexpected] prev not sorted; sorting")
sortNodes(prev)
}
newFull := make([]*tailcfg.Node, 0, len(prev)-len(removed))
for len(prev) > 0 && len(changed) > 0 {
pID := prev[0].ID
cID := changed[0].ID
if removed[pID] {
prev = prev[1:]
continue
}
switch {
case pID < cID:
newFull = append(newFull, prev[0])
prev = prev[1:]
case pID == cID:
newFull = append(newFull, changed[0])
prev, changed = prev[1:], changed[1:]
case cID < pID:
newFull = append(newFull, changed[0])
changed = changed[1:]
}
}
newFull = append(newFull, changed...)
for _, n := range prev {
if !removed[n.ID] {
newFull = append(newFull, n)
}
}
sortNodes(newFull)
mapRes.Peers = newFull
mapRes.PeersChanged = nil
mapRes.PeersRemoved = nil
}
func nodesSorted(v []*tailcfg.Node) bool {
for i, n := range v {
if i > 0 && n.ID <= v[i-1].ID {
return false
}
}
return true
}
func sortNodes(v []*tailcfg.Node) {
sort.Slice(v, func(i, j int) bool { return v[i].ID < v[j].ID })
}
func cloneNodes(v1 []*tailcfg.Node) []*tailcfg.Node {
if v1 == nil {
return nil
}
v2 := make([]*tailcfg.Node, len(v1))
for i, n := range v1 {
v2[i] = n.Clone()
}
return v2
}
// 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.
func ipForwardingBroken(routes []wgcfg.CIDR) 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
}
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
}
return strings.TrimSpace(string(out)) == "0"
// TODO: also check IPv6 if 'routes' contains any IPv6 routes
}