hardened ipn.State enum (#16)

* hardened ipn.State enum

* nit

* Comment NewIPNStateFromString

* nit v2

---------

Co-authored-by: Lexi Mattick <[email protected]>

libts/state.go

@@ -2,6 +2,7 @@ package libts
 
 import (
 	"context"
+	"fmt"
 	"slices"
 	"strings"
 
@@ -17,9 +18,8 @@ type State struct {
 	Prefs *ipn.Prefs
 
 	// Current Tailscale backend state.
-	//  "NoState", "NeedsLogin", "NeedsMachineAuth", "Stopped",
-	//  "Starting", "Running".
-	BackendState string
+	BackendState ipn.State
+
 	// Current Tailscale version. This is a shortened version string like "1.70.0".
 	TSVersion string
 
@@ -70,6 +70,31 @@ func getSortedExitNodes(tsStatus *ipnstate.Status) []*ipnstate.PeerStatus {
 	return exitNodes
 }
 
+// Create an ipn.State from the string representation.
+//
+// This string representation comes from Tailscale's API and, because Go does not have
+// proper enums, this is the best way to convert it back to a "typed" representation.
+func NewIPNStateFromString(v string) (ipn.State, error) {
+	switch v {
+	case "NoState":
+		return ipn.NoState, nil
+	case "InUseOtherUser":
+		return ipn.InUseOtherUser, nil
+	case "NeedsLogin":
+		return ipn.NeedsLogin, nil
+	case "NeedsMachineAuth":
+		return ipn.NeedsMachineAuth, nil
+	case "Stopped":
+		return ipn.Stopped, nil
+	case "Starting":
+		return ipn.Starting, nil
+	case "Running":
+		return ipn.Running, nil
+	default:
+		return ipn.NoState, fmt.Errorf("unknown ipn state: %s", v)
+	}
+}
+
 // Make a current State by making necessary Tailscale API calls.
 func GetState(ctx context.Context) (State, error) {
 	status, err := Status(ctx)
@@ -87,10 +112,15 @@ func GetState(ctx context.Context) (State, error) {
 		return State{}, err
 	}
 
+	backendState, err := NewIPNStateFromString(status.BackendState)
+	if err != nil {
+		return State{}, fmt.Errorf("cannot get status from state: %w", err)
+	}
+
 	state := State{
 		Prefs:           prefs,
 		AuthURL:         status.AuthURL,
-		BackendState:    status.BackendState,
+		BackendState:    backendState,
 		TSVersion:       status.Version,
 		Self:            status.Self,
 		SortedExitNodes: getSortedExitNodes(status),
@@ -114,7 +144,7 @@ func GetState(ctx context.Context) (State, error) {
 	if lock.Enabled && lock.NodeKey != nil && !lock.PublicKey.IsZero() {
 		state.LockKey = &lock.PublicKey
 
-		if !lock.NodeKeySigned && state.BackendState == ipn.Running.String() {
+		if !lock.NodeKeySigned && state.BackendState == ipn.Running {
 			state.IsLockedOut = true
 		}
 	}

menus.go

@@ -17,7 +17,7 @@ import (
 
 // Update all of the menu UIs from the current state.
 func (m *model) updateMenus() {
-	if m.state.BackendState == ipn.Running.String() {
+	if m.state.BackendState == ipn.Running {
 		// Update the device info submenu.
 		{
 			submenuItems := []ui.SubmenuItem{

update.go

@@ -137,7 +137,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		case ".":
 			switch m.state.BackendState {
 			// If running, stop Tailscale.
-			case ipn.Running.String():
+			case ipn.Running:
 				return m, func() tea.Msg {
 					err := libts.Down(ctx)
 					if err != nil {
@@ -147,7 +147,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 				}
 
 			// If stopped, start Tailscale.
-			case ipn.Stopped.String():
+			case ipn.Stopped:
 				return m, func() tea.Msg {
 					err := libts.Up(ctx)
 					if err != nil {
@@ -157,7 +157,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 				}
 
 			// If we need to login...
-			case ipn.NeedsLogin.String():
+			case ipn.NeedsLogin:
 				if m.state.AuthURL == "" {
 					// If we haven't started the login flow yet, do so.
 					// Tailscale will open their browser for us.
@@ -179,7 +179,7 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 					}
 				}
 
-			case ipn.Starting.String():
+			case ipn.Starting:
 				// If we have an AuthURL in the Starting state, that means the user is reauthenticating
 				// and we also need to open the browser!
 				// (But not if we're root on Linux.)

view.go

@@ -11,30 +11,30 @@ import (
 )
 
 // Format the status button in the header bar.
-func renderStatusButton(backendState string, isUsingExitNode bool) string {
+func renderStatusButton(backendState ipn.State, isUsingExitNode bool) string {
 	buttonStyle := lipgloss.NewStyle().
 		Padding(0, 1)
 
 	switch backendState {
-	case ipn.NeedsLogin.String():
+	case ipn.NeedsLogin:
 		return buttonStyle.
 			Background(ui.Yellow).
 			Foreground(ui.Black).
 			Render("Needs Login")
 
-	case ipn.NeedsMachineAuth.String():
+	case ipn.NeedsMachineAuth:
 		return buttonStyle.
 			Background(ui.Yellow).
 			Foreground(ui.Black).
 			Render("Needs Machine Auth")
 
-	case ipn.Starting.String():
+	case ipn.Starting:
 		return buttonStyle.
 			Background(ui.Blue).
 			Foreground(ui.White).
 			Render("Starting...")
 
-	case ipn.Running.String():
+	case ipn.Running:
 		text := "Connected"
 		if isUsingExitNode {
 			text += " - Exit Node"
@@ -45,13 +45,13 @@ func renderStatusButton(backendState string, isUsingExitNode bool) string {
 			Foreground(ui.Black).
 			Render(text)
 
-	case ipn.Stopped.String():
+	case ipn.Stopped:
 		return buttonStyle.
 			Background(ui.Red).
 			Foreground(ui.Black).
 			Render("Not Connected")
 
-	case ipn.NoState.String():
+	case ipn.NoState:
 		return buttonStyle.
 			Background(ui.Blue).
 			Foreground(ui.White).
@@ -93,7 +93,7 @@ func renderHeader(m *model) string {
 		var status strings.Builder
 		status.WriteString("Status: ")
 		status.WriteString(renderStatusButton(m.state.BackendState, m.state.CurrentExitNode != nil))
-		if m.state.BackendState == ipn.Running.String() {
+		if m.state.BackendState == ipn.Running {
 			status.WriteString(lipgloss.NewStyle().
 				Faint(true).
 				PaddingLeft(1).
@@ -154,7 +154,7 @@ func renderMiddleBanner(m *model, height int, text string) string {
 func renderStatusBar(m *model) string {
 	var text string
 
-	if m.statusText == "" && m.canWrite && m.state.BackendState == ipn.Running.String() {
+	if m.statusText == "" && m.canWrite && m.state.BackendState == ipn.Running {
 		// If there's no other status, we're running, and we have write access, show up/down.
 		text = lipgloss.NewStyle().
 			Faint(true).
@@ -242,16 +242,16 @@ func (m model) View() string {
 		Render(m.state.AuthURL)
 
 	switch m.state.BackendState {
-	case ipn.Running.String():
+	case ipn.Running:
 		middle = lipgloss.NewStyle().
 			Height(middleHeight).
 			Render(m.menu.Render(middleHeight))
 
-	case ipn.NeedsMachineAuth.String():
+	case ipn.NeedsMachineAuth:
 		// TODO: Figure out what this state actually is so we can be helpful to the user.
 		middle = renderMiddleBanner(&m, middleHeight, "Tailscale status is NeedsMachineAuth.")
 
-	case ipn.NeedsLogin.String():
+	case ipn.NeedsLogin:
 		lines := []string{
 			lipgloss.NewStyle().
 				Bold(true).
@@ -280,17 +280,17 @@ func (m model) View() string {
 
 		middle = renderMiddleBanner(&m, middleHeight, strings.Join(lines, "\n"))
 
-	case ipn.Stopped.String():
+	case ipn.Stopped:
 		middle = renderMiddleBanner(&m, middleHeight, strings.Join([]string{
 			`The Tailscale daemon isn't running.`,
 			``,
 			`Press . to bring Tailscale up.`,
 		}, "\n"))
 
-	case ipn.NoState.String():
+	case ipn.NoState:
 		middle = renderMiddleBanner(&m, middleHeight, ui.PoggersAnimationFrame(m.animationT))
 
-	case ipn.Starting.String():
+	case ipn.Starting:
 		if m.state.AuthURL == "" {
 			middle = renderMiddleBanner(&m, middleHeight, ui.PoggersAnimationFrame(m.animationT))
 		} else {