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ipn/ipnserver: remove IPN protocol server

Browse Source 
Unused in this repo as of the earlier #6450 (300aba61a6)
and unused in the Windows GUI as of tailscale/corp#8065.

With this ipn.BackendServer is no longer used and could also be
removed from this repo. The macOS and iOS clients still temporarily
depend on it, but I can move it to that repo instead while and let its
migration proceed on its own schedule while we clean this repo up.

Updates #6417
Updates tailscale/corp#8051

Change-Id: Ie13f82af3eb9f96b3a21c56cdda51be31ddebdcf
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
pull/6515/head
Brad Fitzpatrick 1 year ago committed by Brad Fitzpatrick
parent 624d9c759b
commit 7e016c1d90
7 changed files with 32 additions and 759 deletions
Show Stats Download Patch File Download Diff File

8
cmd/tailscale/cli/up.go
Unescape Escape View File

@ -571,14 +571,6 @@ func runUp(ctx context.Context, cmd string, args []string, upArgs upArgsT) (retE
}
if n.ErrMessage != nil {
msg := *n.ErrMessage
if msg == ipn.ErrMsgPermissionDenied {
switch effectiveGOOS() {
case "windows":
msg += " (Tailscale service in use by other user?)"
default:
msg += " (try 'sudo tailscale up [...]')"
}
}
fatalf("backend error: %v\n", msg)
}
if s := n.State; s != nil {

9
cmd/tailscale/cli/web.go
Unescape Escape View File

@ -23,7 +23,6 @@ import (
"net/url"
"os"
"os/exec"
"runtime"
"strings"
"github.com/peterbourgon/ff/v3/ffcli"
@ -470,14 +469,6 @@ func tailscaleUp(ctx context.Context, st *ipnstate.Status, forceReauth bool) (au
}
if n.ErrMessage != nil {
msg := *n.ErrMessage
if msg == ipn.ErrMsgPermissionDenied {
switch runtime.GOOS {
case "windows":
msg += " (Tailscale service in use by other user?)"
default:
msg += " (try 'sudo tailscale up [...]')"
}
}
return "", fmt.Errorf("backend error: %v", msg)
}
if url := n.BrowseToURL; url != nil && printAuthURL(*url) {

295
ipn/ipnserver/server.go
Unescape Escape View File

@ -6,10 +6,7 @@ package ipnserver
import (
"bufio"
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"log"
@ -38,11 +35,9 @@ import (
"tailscale.com/net/dnsfallback"
"tailscale.com/net/netutil"
"tailscale.com/net/tsdial"
"tailscale.com/safesocket"
"tailscale.com/smallzstd"
"tailscale.com/types/logger"
"tailscale.com/util/systemd"
"tailscale.com/version"
"tailscale.com/version/distro"
"tailscale.com/wgengine"
"tailscale.com/wgengine/monitor"
@ -97,66 +92,16 @@ type Server struct {
// is true, the ForceDaemon pref can override this.
resetOnZero bool
bsMu sync.Mutex // lock order: bsMu, then mu
bs *ipn.BackendServer
// mu guards the fields that follow.
// lock order: mu, then LocalBackend.mu
mu sync.Mutex
lastUserID string // tracks last userid; on change, Reset state for paranoia
allClients map[net.Conn]*ipnauth.ConnIdentity // HTTP or IPN
clients map[net.Conn]bool // subset of allClients; only IPN protocol
disconnectSub map[chan<- struct{}]struct{} // keys are subscribers of disconnects
mu sync.Mutex
lastUserID string // tracks last userid; on change, Reset state for paranoia
allClients map[net.Conn]*ipnauth.ConnIdentity
}
// LocalBackend returns the server's LocalBackend.
func (s *Server) LocalBackend() *ipnlocal.LocalBackend { return s.b }
// blockWhileInUse blocks while until either a Read from conn fails
// (i.e. it's closed) or until the server is able to accept ci as a
// user.
func (s *Server) blockWhileInUse(conn io.Reader, ci *ipnauth.ConnIdentity) {
s.logf("blocking client while server in use; connIdentity=%v", ci)
connDone := make(chan struct{})
go func() {
io.Copy(io.Discard, conn)
close(connDone)
}()
ch := make(chan struct{}, 1)
s.registerDisconnectSub(ch, true)
defer s.registerDisconnectSub(ch, false)
for {
select {
case <-connDone:
s.logf("blocked client Read completed; connIdentity=%v", ci)
return
case <-ch:
s.mu.Lock()
err := s.checkConnIdentityLocked(ci)
s.mu.Unlock()
if err == nil {
s.logf("unblocking client, server is free; connIdentity=%v", ci)
// Server is now available again for a new user.
// TODO(bradfitz): keep this connection alive. But for
// now just return and have our caller close the connection
// (which unblocks the io.Copy goroutine we started above)
// and then the client (e.g. Windows) will reconnect and
// discover that it works.
return
}
}
}
}
// bufferHasHTTPRequest reports whether br looks like it has an HTTP
// request in it, without reading any bytes from it.
func bufferHasHTTPRequest(br *bufio.Reader) bool {
peek, _ := br.Peek(br.Buffered())
return mem.HasPrefix(mem.B(peek), mem.S("GET ")) ||
mem.HasPrefix(mem.B(peek), mem.S("POST ")) ||
mem.Contains(mem.B(peek), mem.S(" HTTP/"))
}
// bufferIsConnect reports whether br looks like it's likely an HTTP
// CONNECT request.
//
@ -166,38 +111,11 @@ func bufferIsConnect(br *bufio.Reader) bool {
return mem.HasPrefix(mem.B(peek), mem.S("CONN"))
}
// permitOldProtocol is whether we permit the old pre-HTTP protocol from the
// client (cmd/tailscale or GUI client) to the tailscaled server.
//
// This is currently (2022-11-24) only permitted on Windows. There is an
// outstanding change to the Windows GUI to finish the migration to the
// HTTP-based protocol. Once it's in, this constant will go away and the old
// protocol will not be permitted for any platform.
const permitOldProtocol = runtime.GOOS == "windows"
// ipnProtoAndMethodSniffTimeout returns the read timeout to try to read a few
// bytes from incoming IPN connection to determine whether it's an old-style
// IPN bus connection or a new-style HTTP connection. And if an HTTP connection,
// what its HTTP method is.
func ipnProtoAndMethodSniffTimeout() time.Duration {
if permitOldProtocol {
// In the old protocol, the client might not be sending anything at all
// and only receiving, so keep a short timeout as to not delay
// connecting to the IPN bus and getting ipn.Notify messages.
return 1 * time.Second
}
// But in the new protocol, there will always be an HTTP request to start,
// so we can take a long time to receive the first few bytes. 30s is
// overkill.
return 30 * time.Second
}
func (s *Server) serveConn(ctx context.Context, c net.Conn, logf logger.Logf) {
// First sniff a few bytes to see if it's an HTTP request. And if so, which
// HTTP method.
// First sniff a few bytes to check its HTTP method.
br := bufio.NewReader(c)
c.SetReadDeadline(time.Now().Add(ipnProtoAndMethodSniffTimeout()))
br.Peek(4) // either 4 bytes old protocol length header, or HTTP "GET " etc.
c.SetReadDeadline(time.Now().Add(30 * time.Second))
br.Peek(len("GET / HTTP/1.1\r\n")) // reasonable sniff size to get HTTP method
c.SetReadDeadline(time.Time{})
// Handle logtail CONNECT requests early. (See docs on handleProxyConnectConn)
@ -206,78 +124,28 @@ func (s *Server) serveConn(ctx context.Context, c net.Conn, logf logger.Logf) {
return
}
// If we don't permit the old "IPN bus" JSON bidi stream protocol, then
// assume it's HTTP. Otherwise sniff the first few bytes to see if it looks
// like HTTP.
isHTTPReq := !permitOldProtocol || bufferHasHTTPRequest(br)
ci, err := s.addConn(c, isHTTPReq)
ci, err := s.addConn(c)
if err != nil {
if isHTTPReq {
fmt.Fprintf(c, "HTTP/1.0 500 Nope\r\nContent-Type: text/plain\r\nX-Content-Type-Options: nosniff\r\n\r\n%s\n", err.Error())
c.Close()
return
}
defer c.Close()
bs := ipn.NewBackendServer(logf, nil, jsonNotifier(c, s.logf))
_, occupied := err.(inUseOtherUserError)
if occupied {
bs.SendInUseOtherUserErrorMessage(err.Error())
s.blockWhileInUse(c, ci)
} else {
bs.SendErrorMessage(err.Error())
time.Sleep(time.Second)
}
return
fmt.Fprintf(c, "HTTP/1.0 500 Nope\r\nContent-Type: text/plain\r\nX-Content-Type-Options: nosniff\r\n\r\n%s\n", err.Error())
c.Close()
}
// Tell the LocalBackend about the identity we're now running as.
s.b.SetCurrentUserID(ci.UserID())
if isHTTPReq {
httpServer := &http.Server{
// Localhost connections are cheap; so only do
// keep-alives for a short period of time, as these
// active connections lock the server into only serving
// that user. If the user has this page open, we don't
// want another switching user to be locked out for
// minutes. 5 seconds is enough to let browser hit
// favicon.ico and such.
IdleTimeout: 5 * time.Second,
ErrorLog: logger.StdLogger(logf),
Handler: s.localhostHandler(ci),
}
httpServer.Serve(netutil.NewOneConnListener(&protoSwitchConn{s: s, br: br, Conn: c}, nil))
return
}
defer s.removeAndCloseConn(c)
logf("[v1] incoming control connection")
if ci.IsReadonlyConn(s.b.OperatorUserID(), logf) {
ctx = ipn.ReadonlyContextOf(ctx)
}
for ctx.Err() == nil {
msg, err := ipn.ReadMsg(br)
if err != nil {
if errors.Is(err, io.EOF) {
logf("[v1] ReadMsg: %v", err)
} else if ctx.Err() == nil {
logf("ReadMsg: %v", err)
}
return
}
s.bsMu.Lock()
if err := s.bs.GotCommandMsg(ctx, msg); err != nil {
logf("GotCommandMsg: %v", err)
}
gotQuit := s.bs.GotQuit
s.bsMu.Unlock()
if gotQuit {
return
}
httpServer := &http.Server{
// Localhost connections are cheap; so only do
// keep-alives for a short period of time, as these
// active connections lock the server into only serving
// that user. If the user has this page open, we don't
// want another switching user to be locked out for
// minutes. 5 seconds is enough to let browser hit
// favicon.ico and such.
IdleTimeout: 5 * time.Second,
ErrorLog: logger.StdLogger(logf),
Handler: s.localhostHandler(ci),
}
httpServer.Serve(netutil.NewOneConnListener(&protoSwitchConn{s: s, br: br, Conn: c}, nil))
}
// inUseOtherUserError is the error type for when the server is in use
@ -375,27 +243,11 @@ func (s *Server) connCanFetchCerts(ci *ipnauth.ConnIdentity) bool {
return false
}
// registerDisconnectSub adds ch as a subscribe to connection disconnect
// events. If add is false, the subscriber is removed.
func (s *Server) registerDisconnectSub(ch chan<- struct{}, add bool) {
s.mu.Lock()
defer s.mu.Unlock()
if add {
if s.disconnectSub == nil {
s.disconnectSub = make(map[chan<- struct{}]struct{})
}
s.disconnectSub[ch] = struct{}{}
} else {
delete(s.disconnectSub, ch)
}
}
// addConn adds c to the server's list of clients.
//
// If the returned error is of type inUseOtherUserError then the
// returned connIdentity is also valid.
func (s *Server) addConn(c net.Conn, isHTTP bool) (ci *ipnauth.ConnIdentity, err error) {
func (s *Server) addConn(c net.Conn) (ci *ipnauth.ConnIdentity, err error) {
ci, err = ipnauth.GetConnIdentity(s.logf, c)
if err != nil {
return
@ -414,9 +266,6 @@ func (s *Server) addConn(c net.Conn, isHTTP bool) (ci *ipnauth.ConnIdentity, err
s.mu.Lock()
defer s.mu.Unlock()
if s.clients == nil {
s.clients = map[net.Conn]bool{}
}
if s.allClients == nil {
s.allClients = map[net.Conn]*ipnauth.ConnIdentity{}
}
@ -425,9 +274,6 @@ func (s *Server) addConn(c net.Conn, isHTTP bool) (ci *ipnauth.ConnIdentity, err
return ci, err
}
if !isHTTP {
s.clients[c] = true
}
s.allClients[c] = ci
if s.lastUserID != ci.UserID() {
@ -441,15 +287,8 @@ func (s *Server) addConn(c net.Conn, isHTTP bool) (ci *ipnauth.ConnIdentity, err
func (s *Server) removeAndCloseConn(c net.Conn) {
s.mu.Lock()
delete(s.clients, c)
delete(s.allClients, c)
remain := len(s.allClients)
for sub := range s.disconnectSub {
select {
case sub <- struct{}{}:
default:
}
}
s.mu.Unlock()
if remain == 0 && s.resetOnZero {
@ -463,36 +302,6 @@ func (s *Server) removeAndCloseConn(c net.Conn) {
c.Close()
}
func (s *Server) stopAll() {
s.mu.Lock()
defer s.mu.Unlock()
for c := range s.clients {
safesocket.ConnCloseRead(c)
safesocket.ConnCloseWrite(c)
}
s.clients = nil
}
var jsonEscapedZero = []byte(`\u0000`)
func (s *Server) writeToClients(n ipn.Notify) {
s.mu.Lock()
defer s.mu.Unlock()
if len(s.clients) == 0 {
// Common case (at least on busy servers): nobody
// connected (no GUI, etc), so return before
// serializing JSON.
return
}
if b, ok := marshalNotify(n, s.logf); ok {
for c := range s.clients {
ipn.WriteMsg(c, b)
}
}
}
// Run runs a Tailscale backend service.
// The getEngine func is called repeatedly, once per connection, until it returns an engine successfully.
//
@ -502,9 +311,6 @@ func Run(ctx context.Context, logf logger.Logf, ln net.Listener, store ipn.State
runDone := make(chan struct{})
defer close(runDone)
var serverMu sync.Mutex
var serverOrNil *Server
// When the context is closed or when we return, whichever is first, close our listener
// and all open connections.
go func() {
@ -512,11 +318,6 @@ func Run(ctx context.Context, logf logger.Logf, ln net.Listener, store ipn.State
case <-ctx.Done():
case <-runDone:
}
serverMu.Lock()
if s := serverOrNil; s != nil {
s.stopAll()
}
serverMu.Unlock()
ln.Close()
}()
logf("Listening on %v", ln.Addr())
@ -542,13 +343,10 @@ func Run(ctx context.Context, logf logger.Logf, ln net.Listener, store ipn.State
break
}
logf("ipnserver%d: getEngine failed again: %v", i, err)
errMsg := err.Error()
go func() {
defer c.Close()
bs := ipn.NewBackendServer(logf, nil, jsonNotifier(c, logf))
bs.SendErrorMessage(errMsg)
time.Sleep(time.Second)
}()
// TODO(bradfitz): queue this error up for the next IPN bus watcher call
// to get for the Windows GUI? We used to send it over the pre-HTTP
// protocol to the Windows GUI. Just close it.
c.Close()
}
if err := ctx.Err(); err != nil {
return err
@ -568,9 +366,6 @@ func Run(ctx context.Context, logf logger.Logf, ln net.Listener, store ipn.State
if ns != nil {
ns.SetLocalBackend(server.LocalBackend())
}
serverMu.Lock()
serverOrNil = server
serverMu.Unlock()
return server.Run(ctx, ln)
}
@ -613,7 +408,6 @@ func New(logf logger.Logf, logid string, store ipn.StateStore, eng wgengine.Engi
logf: logf,
resetOnZero: !opts.SurviveDisconnects,
}
server.bs = ipn.NewBackendServer(logf, b, server.writeToClients)
return server, nil
}
@ -633,17 +427,11 @@ func (s *Server) Run(ctx context.Context, ln net.Listener) error {
case <-ctx.Done():
case <-runDone:
}
s.stopAll()
ln.Close()
}()
if s.b.Prefs().Valid() {
s.bs.GotCommand(ctx, &ipn.Command{
Version: version.Long,
Start: &ipn.StartArgs{
Opts: ipn.Options{},
},
})
s.b.Start(ipn.Options{})
}
systemd.Ready()
@ -815,10 +603,9 @@ func getEngineUntilItWorksWrapper(getEngine func() (wgengine.Engine, *netstack.I
}
}
// protoSwitchConn is a net.Conn that's we want to speak HTTP to but
// it's already had a few bytes read from it to determine that it's
// HTTP. So we Read from its bufio.Reader. On Close, we we tell the
// server it's closed, so the server can account the who's connected.
// protoSwitchConn is a net.Conn with which we want to speak HTTP to but
// it's already had a few bytes read from it to determine its HTTP method.
// So we Read from its bufio.Reader. On Close, we we tell the
type protoSwitchConn struct {
s *Server
net.Conn
@ -870,28 +657,6 @@ func (s *Server) ServeHTMLStatus(w http.ResponseWriter, r *http.Request) {
st.WriteHTML(w)
}
// jsonNotifier returns a notify-writer func that writes ipn.Notify
// messages to w.
func jsonNotifier(w io.Writer, logf logger.Logf) func(ipn.Notify) {
return func(n ipn.Notify) {
if b, ok := marshalNotify(n, logf); ok {
ipn.WriteMsg(w, b)
}
}
}
func marshalNotify(n ipn.Notify, logf logger.Logf) (b []byte, ok bool) {
b, err := json.Marshal(n)
if err != nil {
logf("ipnserver: [unexpected] error serializing JSON: %v", err)
return nil, false
}
if bytes.Contains(b, jsonEscapedZero) {
logf("[unexpected] zero byte in BackendServer.send notify message: %q", b)
}
return b, true
}
// listenerWithReadyConn is a net.Listener wrapper that has
// one net.Conn ready to be accepted already.
type listenerWithReadyConn struct {

86
ipn/ipnserver/server_test.go
Unescape Escape View File

@ -1,86 +0,0 @@
// 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 ipnserver_test
import (
"context"
"fmt"
"path/filepath"
"strings"
"testing"
"tailscale.com/ipn"
"tailscale.com/ipn/ipnserver"
"tailscale.com/ipn/store/mem"
"tailscale.com/net/tsdial"
"tailscale.com/safesocket"
"tailscale.com/wgengine"
"tailscale.com/wgengine/netstack"
)
func TestRunMultipleAccepts(t *testing.T) {
t.Skipf("TODO(bradfitz): finish this test, once other fires are out")
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
td := t.TempDir()
socketPath := filepath.Join(td, "tailscale.sock")
logf := func(format string, args ...any) {
format = strings.TrimRight(format, "\n")
println(fmt.Sprintf(format, args...))
t.Logf(format, args...)
}
s := safesocket.DefaultConnectionStrategy(socketPath)
connect := func() {
for i := 1; i <= 2; i++ {
logf("connect %d ...", i)
c, err := safesocket.Connect(s)
if err != nil {
t.Fatalf("safesocket.Connect: %v\n", err)
}
clientToServer := func(b []byte) {
ipn.WriteMsg(c, b)
}
bc := ipn.NewBackendClient(logf, clientToServer)
prefs := ipn.NewPrefs()
bc.SetPrefs(prefs)
c.Close()
}
}
logTriggerTestf := func(format string, args ...any) {
logf(format, args...)
if strings.HasPrefix(format, "Listening on ") {
connect()
}
}
eng, err := wgengine.NewFakeUserspaceEngine(logf, 0)
if err != nil {
t.Fatal(err)
}
t.Cleanup(eng.Close)
opts := ipnserver.Options{}
t.Logf("pre-Run")
store := new(mem.Store)
ln, _, err := safesocket.Listen(socketPath, 0)
if err != nil {
t.Fatal(err)
}
defer ln.Close()
err = ipnserver.Run(ctx, logTriggerTestf, ln, store, nil /* mon */, new(tsdial.Dialer), "dummy_logid", FixedEngine(eng), opts)
t.Logf("ipnserver.Run = %v", err)
}
// FixedEngine returns a func that returns eng and a nil error.
func FixedEngine(eng wgengine.Engine) func() (wgengine.Engine, *netstack.Impl, error) {
return func() (wgengine.Engine, *netstack.Impl, error) { return eng, nil, nil }
}

319
ipn/message.go
Unescape Escape View File

@ -5,19 +5,9 @@
package ipn
import (
"bytes"
"context"
"encoding/binary"
"encoding/json"
"errors"
"fmt"
"io"
"log"
"tailscale.com/envknob"
"tailscale.com/tailcfg"
"tailscale.com/types/logger"
"tailscale.com/types/structs"
"tailscale.com/version"
)
@ -39,178 +29,6 @@ func ReadonlyContextOf(ctx context.Context) context.Context {
return context.WithValue(ctx, readOnlyContextKey{}, readOnlyContextKey{})
}
var jsonEscapedZero = []byte(`\u0000`)
type NoArgs struct{}
type StartArgs struct {
Opts Options
}
type SetPrefsArgs struct {
New *Prefs
}
// Command is a command message that is JSON encoded and sent by a
// frontend to a backend.
type Command struct {
_ structs.Incomparable
// Version is the binary version of the frontend (the client).
Version string
// AllowVersionSkew controls whether it's permitted for the
// client and server to have a different version. The default
// (false) means to be strict.
AllowVersionSkew bool
// Exactly one of the following must be non-nil.
Quit *NoArgs
Start *StartArgs
StartLoginInteractive *NoArgs
Login *tailcfg.Oauth2Token
Logout *NoArgs
SetPrefs *SetPrefsArgs
RequestEngineStatus *NoArgs
RequestStatus *NoArgs
}
type BackendServer struct {
logf logger.Logf
b Backend // the Backend we are serving up
sendNotifyMsg func(Notify) // send a notification message
GotQuit bool // a Quit command was received
}
// NewBackendServer creates a new BackendServer using b.
//
// If sendNotifyMsg is non-nil, it additionally sets the Backend's
// notification callback to call the func with ipn.Notify messages in
// JSON form. If nil, it does not change the notification callback.
func NewBackendServer(logf logger.Logf, b Backend, sendNotifyMsg func(Notify)) *BackendServer {
bs := &BackendServer{
logf: logf,
b: b,
sendNotifyMsg: sendNotifyMsg,
}
// b may be nil if the BackendServer is being created just to
// encapsulate and send an error message.
if sendNotifyMsg != nil && b != nil {
b.SetNotifyCallback(bs.send)
}
return bs
}
func (bs *BackendServer) send(n Notify) {
if bs.sendNotifyMsg == nil {
return
}
n.Version = ipcVersion
bs.sendNotifyMsg(n)
}
func (bs *BackendServer) SendErrorMessage(msg string) {
bs.send(Notify{ErrMessage: &msg})
}
// SendInUseOtherUserErrorMessage sends a Notify message to the client that
// both sets the state to 'InUseOtherUser' and sets the associated reason
// to msg.
func (bs *BackendServer) SendInUseOtherUserErrorMessage(msg string) {
inUse := InUseOtherUser
bs.send(Notify{
State: &inUse,
ErrMessage: &msg,
})
}
// GotCommandMsg parses the incoming message b as a JSON Command and
// calls GotCommand with it.
func (bs *BackendServer) GotCommandMsg(ctx context.Context, b []byte) error {
cmd := &Command{}
if len(b) == 0 {
return nil
}
if err := json.Unmarshal(b, cmd); err != nil {
return err
}
return bs.GotCommand(ctx, cmd)
}
// ErrMsgPermissionDenied is the Notify.ErrMessage value used an
// operation was done from a user/context that didn't have permission.
const ErrMsgPermissionDenied = "permission denied"
func (bs *BackendServer) GotCommand(ctx context.Context, cmd *Command) error {
if cmd.Version != ipcVersion && !cmd.AllowVersionSkew {
vs := fmt.Sprintf("GotCommand: Version mismatch! frontend=%#v backend=%#v",
cmd.Version, ipcVersion)
bs.logf("%s", vs)
// ignore the command, but send a message back to the
// caller so it can realize the version mismatch too.
// We don't want to exit because it might cause a crash
// loop, and restarting won't fix the problem.
bs.send(Notify{
ErrMessage: &vs,
})
return nil
}
// TODO(bradfitz): finish plumbing context down to all the methods below;
// currently we just check for read-only contexts in this method and
// then never use contexts again.
// Actions permitted with a read-only context:
if c := cmd.RequestEngineStatus; c != nil {
bs.b.RequestEngineStatus()
return nil
}
if IsReadonlyContext(ctx) {
msg := ErrMsgPermissionDenied
bs.send(Notify{ErrMessage: &msg})
return nil
}
if cmd.Quit != nil {
bs.GotQuit = true
return errors.New("Quit command received")
} else if c := cmd.Start; c != nil {
opts := c.Opts
return bs.b.Start(opts)
} else if c := cmd.StartLoginInteractive; c != nil {
bs.b.StartLoginInteractive()
return nil
} else if c := cmd.Login; c != nil {
bs.b.Login(c)
return nil
} else if c := cmd.Logout; c != nil {
bs.b.Logout()
return nil
} else if c := cmd.SetPrefs; c != nil {
bs.b.SetPrefs(c.New)
return nil
}
return fmt.Errorf("BackendServer.Do: no command specified")
}
type BackendClient struct {
logf logger.Logf
sendCommandMsg func(jsonb []byte)
notify func(Notify)
// AllowVersionSkew controls whether to allow mismatched
// frontend & backend versions.
AllowVersionSkew bool
}
func NewBackendClient(logf logger.Logf, sendCommandMsg func(jsonb []byte)) *BackendClient {
return &BackendClient{
logf: logf,
sendCommandMsg: sendCommandMsg,
}
}
// IPCVersion returns version.Long usually, unless TS_DEBUG_FAKE_IPC_VERSION is
// set, in which it contains that value. This is only used for weird development
// cases when testing mismatched versions and you want the client to act like it's
@ -221,140 +39,3 @@ func IPCVersion() string {
}
return version.Long
}
var ipcVersion = IPCVersion()
func (bc *BackendClient) GotNotifyMsg(b []byte) {
if len(b) == 0 {
// not interesting
return
}
if bytes.Contains(b, jsonEscapedZero) {
log.Printf("[unexpected] zero byte in BackendClient.GotNotifyMsg message: %q", b)
}
n := Notify{}
if err := json.Unmarshal(b, &n); err != nil {
log.Fatalf("BackendClient.Notify: cannot decode message (length=%d, %#q): %v", len(b), b, err)
}
if n.Version != ipcVersion && !bc.AllowVersionSkew {
vs := fmt.Sprintf("GotNotify: Version mismatch! frontend=%#v backend=%#v",
ipcVersion, n.Version)
bc.logf("%s", vs)
// delete anything in the notification except the version,
// to prevent incorrect operation.
n = Notify{
Version: n.Version,
ErrMessage: &vs,
}
}
if bc.notify != nil {
bc.notify(n)
}
}
func (bc *BackendClient) send(cmd Command) {
cmd.Version = ipcVersion
b, err := json.Marshal(cmd)
if err != nil {
log.Fatalf("Failed json.Marshal(cmd): %v\n", err)
}
if bytes.Contains(b, jsonEscapedZero) {
log.Printf("[unexpected] zero byte in BackendClient.send command")
}
bc.sendCommandMsg(b)
}
func (bc *BackendClient) SetNotifyCallback(fn func(Notify)) {
bc.notify = fn
}
func (bc *BackendClient) Quit() error {
bc.send(Command{Quit: &NoArgs{}})
return nil
}
func (bc *BackendClient) Start(opts Options) error {
bc.send(Command{Start: &StartArgs{Opts: opts}})
return nil // remote Start() errors must be handled remotely
}
func (bc *BackendClient) StartLoginInteractive() {
bc.send(Command{StartLoginInteractive: &NoArgs{}})
}
func (bc *BackendClient) Login(token *tailcfg.Oauth2Token) {
bc.send(Command{Login: token})
}
func (bc *BackendClient) Logout() {
bc.send(Command{Logout: &NoArgs{}})
}
func (bc *BackendClient) SetPrefs(new *Prefs) {
bc.send(Command{SetPrefs: &SetPrefsArgs{New: new}})
}
func (bc *BackendClient) RequestEngineStatus() {
bc.send(Command{RequestEngineStatus: &NoArgs{}})
}
func (bc *BackendClient) RequestStatus() {
bc.send(Command{AllowVersionSkew: true, RequestStatus: &NoArgs{}})
}
// MaxMessageSize is the maximum message size, in bytes.
const MaxMessageSize = 10 << 20
// TODO(apenwarr): incremental json decode? That would let us avoid
// storing the whole byte array uselessly in RAM.
func ReadMsg(r io.Reader) ([]byte, error) {
cb := make([]byte, 4)
_, err := io.ReadFull(r, cb)
if err != nil {
return nil, err
}
n := binary.LittleEndian.Uint32(cb)
if n > MaxMessageSize {
return nil, fmt.Errorf("ipn.Read: message too large: %v bytes", n)
}
b := make([]byte, n)
nn, err := io.ReadFull(r, b)
if err != nil {
return nil, err
}
if nn != int(n) {
return nil, fmt.Errorf("ipn.Read: expected %v bytes, got %v", n, nn)
}
return b, nil
}
func WriteMsg(w io.Writer, b []byte) error {
// TODO(apenwarr): incremental json encode? That would save RAM, at the
// expense of having to encode once so that we can produce the initial byte
// count.
// TODO(bradfitz): this does two writes to w, which likely
// does two writes on the wire, two frame generations, etc. We
// should take a concrete buffered type, or use a sync.Pool to
// allocate a buf and do one write.
cb := make([]byte, 4)
if len(b) > MaxMessageSize {
return fmt.Errorf("ipn.Write: message too large: %v bytes", len(b))
}
binary.LittleEndian.PutUint32(cb, uint32(len(b)))
n, err := w.Write(cb)
if err != nil {
return err
}
if n != 4 {
return fmt.Errorf("ipn.Write: short write: %v bytes (wanted 4)", n)
}
n, err = w.Write(b)
if err != nil {
return err
}
if n != len(b) {
return fmt.Errorf("ipn.Write: short write: %v bytes (wanted %v)", n, len(b))
}
return nil
}

72
ipn/message_test.go
Unescape Escape View File

@ -1,72 +0,0 @@
// 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 ipn
import (
"bytes"
"testing"
"tailscale.com/tstest"
)
func TestReadWrite(t *testing.T) {
tstest.PanicOnLog()
tstest.ResourceCheck(t)
buf := bytes.Buffer{}
err := WriteMsg(&buf, []byte("Test string1"))
if err != nil {
t.Fatalf("write1: %v\n", err)
}
err = WriteMsg(&buf, []byte(""))
if err != nil {
t.Fatalf("write2: %v\n", err)
}
err = WriteMsg(&buf, []byte("Test3"))
if err != nil {
t.Fatalf("write3: %v\n", err)
}
b, err := ReadMsg(&buf)
if err != nil {
t.Fatalf("read1 error: %v", err)
}
if want, got := "Test string1", string(b); want != got {
t.Fatalf("read1: %#v != %#v\n", want, got)
}
b, err = ReadMsg(&buf)
if err != nil {
t.Fatalf("read2 error: %v", err)
}
if want, got := "", string(b); want != got {
t.Fatalf("read2: %#v != %#v\n", want, got)
}
b, err = ReadMsg(&buf)
if err != nil {
t.Fatalf("read3 error: %v", err)
}
if want, got := "Test3", string(b); want != got {
t.Fatalf("read3: %#v != %#v\n", want, got)
}
b, err = ReadMsg(&buf)
if err == nil {
t.Fatalf("read4: expected error, got %#v\n", b)
}
}
func TestNilBackend(t *testing.T) {
var called *Notify
bs := NewBackendServer(t.Logf, nil, func(n Notify) {
called = &n
})
bs.SendErrorMessage("Danger, Will Robinson!")
if called == nil {
t.Errorf("expect callback to be called, wasn't")
}
if called.ErrMessage == nil || *called.ErrMessage != "Danger, Will Robinson!" {
t.Errorf("callback got wrong error: %v", called.ErrMessage)
}
}

2
ipn/prefs.go
Unescape Escape View File

@ -665,6 +665,8 @@ func PrefsFromBytes(b []byte) (*Prefs, error) {
return p, err
}
var jsonEscapedZero = []byte(`\u0000`)
// LoadPrefs loads a legacy relaynode config file into Prefs
// with sensible migration defaults set.
func LoadPrefs(filename string) (*Prefs, error) {

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