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ipn/ipnserver: remove IPN protocol server

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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>
This commit is contained in:
Brad Fitzpatrick
2022-11-25 07:54:57 -08:00
committed by Brad Fitzpatrick
parent 624d9c759b
commit 7e016c1d90
7 changed files with 32 additions and 759 deletions
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ipn/message.go
-319
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
}