tailscale/ipn/store.go

115 lines
4.0 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package ipn
import (
"bytes"
"context"
"errors"
"fmt"
"net"
"strconv"
)
// ErrStateNotExist is returned by StateStore.ReadState when the
// requested state ID doesn't exist.
var ErrStateNotExist = errors.New("no state with given ID")
const (
// MachineKeyStateKey is the key under which we store the machine key,
// in its key.NodePrivate.MarshalText representation.
MachineKeyStateKey = StateKey("_machinekey")
// LegacyGlobalDaemonStateKey is the ipn.StateKey that tailscaled
// loads on startup.
//
// We have to support multiple state keys for other OSes (Windows in
// particular), but right now Unix daemons run with a single
// node-global state. To keep open the option of having per-user state
// later, the global state key doesn't look like a username.
//
// As of 2022-10-21, it has been superseded by profiles and is no longer
// written to disk. It is only read at startup when there are no profiles,
// to migrate the state to the "default" profile.
// The existing state is left on disk in case the user downgrades to an
// older version of Tailscale that doesn't support profiles. We can
// remove this in a future release.
LegacyGlobalDaemonStateKey = StateKey("_daemon")
// ServerModeStartKey's value, if non-empty, is the value of a
// StateKey containing the prefs to start with which to start the
// server.
//
// For example, the value might be "user-1234", meaning the
// the server should start with the Prefs JSON loaded from
// StateKey "user-1234".
ServerModeStartKey = StateKey("server-mode-start-key")
// KnownProfilesStateKey is the key under which we store the list of
// known profiles. The value is a JSON-encoded []LoginProfile.
KnownProfilesStateKey = StateKey("_profiles")
// CurrentProfileStateKey is the key under which we store the current
// profile.
CurrentProfileStateKey = StateKey("_current-profile")
// TaildropReceivedKey is the key to indicate whether any taildrop file
// has ever been received (even if partially).
// Any non-empty value indicates that at least one file has been received.
TaildropReceivedKey = StateKey("_taildrop-received")
)
// CurrentProfileID returns the StateKey that stores the
// current profile ID. The value is a JSON-encoded LoginProfile.
// If the userID is empty, the key returned is CurrentProfileStateKey,
// otherwise it is "_current/"+userID.
func CurrentProfileKey(userID string) StateKey {
if userID == "" {
return CurrentProfileStateKey
}
return StateKey("_current/" + userID)
}
// StateStore persists state, and produces it back on request.
type StateStore interface {
// ReadState returns the bytes associated with ID. Returns (nil,
// ErrStateNotExist) if the ID doesn't have associated state.
ReadState(id StateKey) ([]byte, error)
// WriteState saves bs as the state associated with ID.
//
// Callers should generally use the ipn.WriteState wrapper func
// instead, which only writes if the value is different from what's
// already in the store.
WriteState(id StateKey, bs []byte) error
}
// WriteState is a wrapper around store.WriteState that only writes if
// the value is different from what's already in the store.
func WriteState(store StateStore, id StateKey, v []byte) error {
if was, err := store.ReadState(id); err == nil && bytes.Equal(was, v) {
return nil
}
return store.WriteState(id, v)
}
// StateStoreDialerSetter is an optional interface that StateStores
// can implement to allow the caller to set a custom dialer.
type StateStoreDialerSetter interface {
SetDialer(d func(ctx context.Context, network, address string) (net.Conn, error))
}
// ReadStoreInt reads an integer from a StateStore.
func ReadStoreInt(store StateStore, id StateKey) (int64, error) {
v, err := store.ReadState(id)
if err != nil {
return 0, err
}
return strconv.ParseInt(string(v), 10, 64)
}
// PutStoreInt puts an integer into a StateStore.
func PutStoreInt(store StateStore, id StateKey, val int64) error {
return WriteState(store, id, fmt.Appendf(nil, "%d", val))
}