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tailscale/ipn/backend.go

135 lines
4.9 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 ipn
import (
"time"
"tailscale.com/control/controlclient"
"tailscale.com/tailcfg"
"tailscale.com/types/empty"
"tailscale.com/wgengine"
)
type State int
const (
NoState = State(iota)
NeedsLogin
NeedsMachineAuth
Stopped
Starting
Running
)
func (s State) String() string {
return [...]string{"NoState", "NeedsLogin", "NeedsMachineAuth",
"Stopped", "Starting", "Running"}[s]
}
// EngineStatus contains WireGuard engine stats.
type EngineStatus struct {
RBytes, WBytes wgengine.ByteCount
NumLive int
LiveDERPs int // number of active DERP connections
LivePeers map[tailcfg.NodeKey]wgengine.PeerStatus
}
type NetworkMap = controlclient.NetworkMap
// Notify is a communication from a backend (e.g. tailscaled) to a frontend
// (cmd/tailscale, iOS, macOS, Win Tasktray).
// In any given notification, any or all of these may be nil, meaning
// that they have not changed.
// They are JSON-encoded on the wire, despite the lack of struct tags.
type Notify struct {
Version string // version number of IPN backend
ErrMessage *string // critical error message, if any
LoginFinished *empty.Message // event: non-nil when login process succeeded
State *State // current IPN state has changed
Prefs *Prefs // preferences were changed
NetMap *NetworkMap // new netmap received
Engine *EngineStatus // wireguard engine stats
BrowseToURL *string // UI should open a browser right now
BackendLogID *string // public logtail id used by backend
// type is mirrored in xcode/Shared/IPN.swift
}
// StateKey is an opaque identifier for a set of LocalBackend state
// (preferences, private keys, etc.).
//
// The reason we need this is that the Tailscale agent may be running
// on a multi-user machine, in a context where a single daemon is
// shared by several consecutive users. Ideally we would just use the
// username of the connected frontend as the StateKey.
//
// However, on Windows, there seems to be no safe way to figure out
// the owning user of a process connected over IPC mechanisms
// (sockets, named pipes). So instead, on Windows, we use a
// capability-oriented system where the frontend generates a random
// identifier for itself, and uses that as the StateKey when talking
// to the backend. That way, while we can't identify an OS user by
// name, we can tell two different users apart, because they'll have
// different opaque state keys (and no access to each others's keys).
type StateKey string
type Options struct {
// FrontendLogID is the public logtail id used by the frontend.
FrontendLogID string
// StateKey and Prefs together define the state the backend should
// use:
// - StateKey=="" && Prefs!=nil: use Prefs for internal state,
// don't persist changes in the backend.
// - StateKey!="" && Prefs==nil: load the given backend-side
// state and use/update that.
// - StateKey!="" && Prefs!=nil: like the previous case, but do
// an initial overwrite of backend state with Prefs.
StateKey StateKey
Prefs *Prefs
// LegacyConfigPath optionally specifies the old-style relaynode
// relay.conf location. If both LegacyConfigPath and StateKey are
// specified and the requested state doesn't exist in the backend
// store, the backend migrates the config from LegacyConfigPath.
//
// TODO(danderson): remove some time after the transition to
// tailscaled is done.
LegacyConfigPath string
// Notify is called when backend events happen.
Notify func(Notify) `json:"-"`
}
// Backend is the interface between Tailscale frontends
// (e.g. cmd/tailscale, iOS/MacOS/Windows GUIs) and the tailscale
// backend (e.g. cmd/tailscaled) running on the same machine.
// (It has nothing to do with the interface between the backends
// and the cloud control plane.)
type Backend interface {
// Start starts or restarts the backend, typically when a
// frontend client connects.
Start(Options) error
// StartLoginInteractive requests to start a new interactive login
// flow. This should trigger a new BrowseToURL notification
// eventually.
StartLoginInteractive()
// Logout terminates the current login session and stops the
// wireguard engine.
Logout()
// SetPrefs installs a new set of user preferences, including
// WantRunning. This may cause the wireguard engine to
// reconfigure or stop.
SetPrefs(*Prefs)
// RequestEngineStatus polls for an update from the wireguard
// engine. Only needed if you want to display byte
// counts. Connection events are emitted automatically without
// polling.
RequestEngineStatus()
// FakeExpireAfter pretends that the current key is going to
// expire after duration x. This is useful for testing GUIs to
// make sure they react properly with keys that are going to
// expire.
FakeExpireAfter(x time.Duration)
}