chore: support operating the VPN without the app (#36)

Author: ethanndickson

Coder Desktop/Coder Desktop/Coder_DesktopApp.swift

@@ -47,9 +47,13 @@ class AppDelegate: NSObject, NSApplicationDelegate {
         }
     }
 
+    // This function MUST eventually call `NSApp.reply(toApplicationShouldTerminate: true)`
+    // or return `.terminateNow`
     func applicationShouldTerminate(_: NSApplication) -> NSApplication.TerminateReply {
+        if !settings.stopVPNOnQuit { return .terminateNow }
         Task {
-            await vpn.quit()
+            await vpn.stop()
+            NSApp.reply(toApplicationShouldTerminate: true)
         }
         return .terminateLater
     }

Coder Desktop/Coder Desktop/NetworkExtension.swift

@@ -24,13 +24,12 @@ enum NetworkExtensionState: Equatable {
 /// An actor that handles configuring, enabling, and disabling the VPN tunnel via the
 /// NetworkExtension APIs.
 extension CoderVPNService {
-    // Updates the UI if a previous configuration exists
-    func loadNetworkExtension() async {
+    func hasNetworkExtensionConfig() async -> Bool {
         do {
-            try await getTunnelManager()
-            neState = .disabled
+            _ = try await getTunnelManager()
+            return true
         } catch {
-            neState = .unconfigured
+            return false
         }
     }
 
@@ -71,37 +70,29 @@ extension CoderVPNService {
         }
     }
 
-    func enableNetworkExtension() async {
+    func startTunnel() async {
         do {
             let tm = try await getTunnelManager()
-            if !tm.isEnabled {
-                tm.isEnabled = true
-                try await tm.saveToPreferences()
-                logger.debug("saved tunnel with enabled=true")
-            }
             try tm.connection.startVPNTunnel()
         } catch {
-            logger.error("enable network extension: \(error)")
+            logger.error("start tunnel: \(error)")
             neState = .failed(error.localizedDescription)
             return
         }
-        logger.debug("enabled and started tunnel")
+        logger.debug("started tunnel")
         neState = .enabled
     }
 
-    func disableNetworkExtension() async {
+    func stopTunnel() async {
         do {
             let tm = try await getTunnelManager()
             tm.connection.stopVPNTunnel()
-            tm.isEnabled = false
-
-            try await tm.saveToPreferences()
         } catch {
-            logger.error("disable network extension: \(error)")
+            logger.error("stop tunnel: \(error)")
             neState = .failed(error.localizedDescription)
             return
         }
-        logger.debug("saved tunnel with enabled=false")
+        logger.debug("stopped tunnel")
         neState = .disabled
     }
 

Coder Desktop/Coder Desktop/State.swift

@@ -104,6 +104,8 @@ class Settings: ObservableObject {
         }
     }
 
+    @AppStorage(Keys.stopVPNOnQuit) var stopVPNOnQuit = true
+
     init(store: UserDefaults = .standard) {
         self.store = store
         _literalHeaders = Published(
@@ -116,6 +118,7 @@ class Settings: ObservableObject {
     enum Keys {
         static let useLiteralHeaders = "UseLiteralHeaders"
         static let literalHeaders = "LiteralHeaders"
+        static let stopVPNOnQuit = "StopVPNOnQuit"
     }
 }
 

Coder Desktop/Coder Desktop/VPNService.swift

@@ -41,7 +41,6 @@ enum VPNServiceError: Error, Equatable {
 final class CoderVPNService: NSObject, VPNService {
     var logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "vpn")
     lazy var xpc: VPNXPCInterface = .init(vpn: self)
-    var terminating = false
     var workspaces: [UUID: String] = [:]
 
     @Published var tunnelState: VPNServiceState = .disabled
@@ -68,8 +67,14 @@ final class CoderVPNService: NSObject, VPNService {
         super.init()
         installSystemExtension()
         Task {
-            await loadNetworkExtension()
+            neState = if await hasNetworkExtensionConfig() {
+                .disabled
+            } else {
+                .unconfigured
+            }
         }
+        xpc.connect()
+        xpc.getPeerState()
         NotificationCenter.default.addObserver(
             self,
             selector: #selector(vpnDidUpdate(_:)),
@@ -82,6 +87,11 @@ final class CoderVPNService: NSObject, VPNService {
         NotificationCenter.default.removeObserver(self)
     }
 
+    func clearPeers() {
+        agents = [:]
+        workspaces = [:]
+    }
+
     func start() async {
         switch tunnelState {
         case .disabled, .failed:
@@ -90,31 +100,18 @@ final class CoderVPNService: NSObject, VPNService {
             return
         }
 
-        await enableNetworkExtension()
-        // this ping is somewhat load bearing since it causes xpc to init
+        await startTunnel()
+        xpc.connect()
         xpc.ping()
         logger.debug("network extension enabled")
     }
 
     func stop() async {
         guard tunnelState == .connected else { return }
-        await disableNetworkExtension()
+        await stopTunnel()
         logger.info("network extension stopped")
     }
 
-    // Instructs the service to stop the VPN and then quit once the stop event
-    // is read over XPC.
-    // MUST only be called from `NSApplicationDelegate.applicationShouldTerminate`
-    // MUST eventually call `NSApp.reply(toApplicationShouldTerminate: true)`
-    func quit() async {
-        guard tunnelState == .connected else {
-            NSApp.reply(toApplicationShouldTerminate: true)
-            return
-        }
-        terminating = true
-        await stop()
-    }
-
     func configureTunnelProviderProtocol(proto: NETunnelProviderProtocol?) {
         Task {
             if let proto {
@@ -145,6 +142,22 @@ final class CoderVPNService: NSObject, VPNService {
         }
     }
 
+    func onExtensionPeerState(_ data: Data?) {
+        guard let data else {
+            logger.error("could not retrieve peer state from network extension, it may not be running")
+            return
+        }
+        logger.info("received network extension peer state")
+        do {
+            let msg = try Vpn_PeerUpdate(serializedBytes: data)
+            debugPrint(msg)
+            clearPeers()
+            applyPeerUpdate(with: msg)
+        } catch {
+            logger.error("failed to decode peer update \(error)")
+        }
+    }
+
     func applyPeerUpdate(with update: Vpn_PeerUpdate) {
         // Delete agents
         update.deletedAgents
@@ -204,9 +217,6 @@ extension CoderVPNService {
         }
         switch connection.status {
         case .disconnected:
-            if terminating {
-                NSApp.reply(toApplicationShouldTerminate: true)
-            }
             connection.fetchLastDisconnectError { err in
                 self.tunnelState = if let err {
                     .failed(.internalError(err.localizedDescription))

Coder Desktop/Coder Desktop/Views/Settings/GeneralTab.swift

@@ -2,11 +2,17 @@ import LaunchAtLogin
 import SwiftUI
 
 struct GeneralTab: View {
+    @EnvironmentObject var settings: Settings
     var body: some View {
         Form {
             Section {
                 LaunchAtLogin.Toggle("Launch at Login")
             }
+            Section {
+                Toggle(isOn: $settings.stopVPNOnQuit) {
+                    Text("Stop VPN on Quit")
+                }
+            }
         }.formStyle(.grouped)
     }
 }

Coder Desktop/Coder Desktop/XPCInterface.swift

@@ -6,11 +6,17 @@ import VPNLib
 @objc final class VPNXPCInterface: NSObject, VPNXPCClientCallbackProtocol, @unchecked Sendable {
     private var svc: CoderVPNService
     private let logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "VPNXPCInterface")
-    private let xpc: VPNXPCProtocol
+    private var xpc: VPNXPCProtocol?
 
     init(vpn: CoderVPNService) {
         svc = vpn
+        super.init()
+    }
 
+    func connect() {
+        guard xpc == nil else {
+            return
+        }
         let networkExtDict = Bundle.main.object(forInfoDictionaryKey: "NetworkExtension") as? [String: Any]
         let machServiceName = networkExtDict?["NEMachServiceName"] as? String
         let xpcConn = NSXPCConnection(machServiceName: machServiceName!)
@@ -21,30 +27,38 @@ import VPNLib
         }
         xpc = proxy
 
-        super.init()
-
         xpcConn.exportedObject = self
         xpcConn.invalidationHandler = { [logger] in
             Task { @MainActor in
                 logger.error("XPC connection invalidated.")
+                self.xpc = nil
             }
         }
         xpcConn.interruptionHandler = { [logger] in
             Task { @MainActor in
                 logger.error("XPC connection interrupted.")
+                self.xpc = nil
             }
         }
         xpcConn.resume()
     }
 
     func ping() {
-        xpc.ping {
+        xpc?.ping {
             Task { @MainActor in
                 self.logger.info("Connected to NE over XPC")
             }
         }
     }
 
+    func getPeerState() {
+        xpc?.getPeerState { data in
+            Task { @MainActor in
+                self.svc.onExtensionPeerState(data)
+            }
+        }
+    }
+
     func onPeerUpdate(_ data: Data) {
         Task { @MainActor in
             svc.onExtensionPeerUpdate(data)

Coder Desktop/VPN/Manager.swift

@@ -194,7 +194,7 @@ actor Manager {
 
     // Retrieves the current state of all peers,
     // as required when starting the app whilst the network extension is already running
-    func getPeerInfo() async throws(ManagerError) -> Vpn_PeerUpdate {
+    func getPeerState() async throws(ManagerError) -> Vpn_PeerUpdate {
         logger.info("sending peer state request")
         let resp: Vpn_TunnelMessage
         do {

Coder Desktop/VPN/XPCInterface.swift

@@ -20,9 +20,12 @@ import VPNLib
         }
     }
 
-    func getPeerInfo(with reply: @escaping () -> Void) {
-        // TODO: Retrieve from Manager
-        reply()
+    func getPeerState(with reply: @escaping (Data?) -> Void) {
+        let reply = CallbackWrapper(reply)
+        Task {
+            let data = try? await manager?.getPeerState().serializedData()
+            reply(data)
+        }
     }
 
     func ping(with reply: @escaping () -> Void) {

Coder Desktop/VPNLib/XPC.swift

@@ -2,7 +2,7 @@ import Foundation
 
 @preconcurrency
 @objc public protocol VPNXPCProtocol {
-    func getPeerInfo(with reply: @escaping () -> Void)
+    func getPeerState(with reply: @escaping (Data?) -> Void)
     func ping(with reply: @escaping () -> Void)
 }