chore: handle waking from device sleep

Author: ethanndickson

Coder Desktop/Coder Desktop/Views/VPNMenu.swift

@@ -5,13 +5,6 @@ struct VPNMenu<VPN: VPNService, S: Session>: View {
     @EnvironmentObject var session: S
     @Environment(\.openSettings) private var openSettings
 
-    // There appears to be a race between the VPN service reporting itself as disconnected,
-    // and the system extension process exiting. When the VPN is toggled off and on quickly,
-    // an error is shown: "The VPN session failed because an internal error occurred".
-    // This forces the user to wait a few seconds before they can toggle the VPN back on.
-    @State private var waitCleanup = false
-    private var waitCleanupDuration: Duration = .seconds(6)
-
     let inspection = Inspection<Self>()
 
     var body: some View {
@@ -23,7 +16,7 @@ struct VPNMenu<VPN: VPNService, S: Session>: View {
                     Toggle(isOn: Binding(
                         get: { vpn.state == .connected || vpn.state == .connecting },
                         set: { isOn in Task {
-                            if isOn { await vpn.start() } else { await stop() }
+                            if isOn { await vpn.start() } else { await vpn.stop() }
                         }
                         }
                     )) {
@@ -93,21 +86,11 @@ struct VPNMenu<VPN: VPNService, S: Session>: View {
     }
 
     private var vpnDisabled: Bool {
-        waitCleanup ||
-            !session.hasSession ||
+        !session.hasSession ||
             vpn.state == .connecting ||
             vpn.state == .disconnecting ||
             vpn.state == .failed(.systemExtensionError(.needsUserApproval))
     }
-
-    private func stop() async {
-        await vpn.stop()
-        waitCleanup = true
-        Task {
-            try? await Task.sleep(for: waitCleanupDuration)
-            waitCleanup = false
-        }
-    }
 }
 
 func openSystemExtensionSettings() {

Coder Desktop/VPN/PacketTunnelProvider.swift

@@ -47,6 +47,11 @@ class PacketTunnelProvider: NEPacketTunnelProvider, @unchecked Sendable {
         options _: [String: NSObject]?, completionHandler: @escaping (Error?) -> Void
     ) {
         logger.info("startTunnel called")
+        start(completionHandler)
+    }
+
+    // called by `startTunnel` and on `wake`
+    func start(_ completionHandler: @escaping (Error?) -> Void) {
         guard manager == nil else {
             logger.error("startTunnel called with non-nil Manager")
             completionHandler(makeNSError(suffix: "PTP", desc: "Already running"))
@@ -95,8 +100,13 @@ class PacketTunnelProvider: NEPacketTunnelProvider, @unchecked Sendable {
         with _: NEProviderStopReason, completionHandler: @escaping () -> Void
     ) {
         logger.debug("stopTunnel called")
+        teardown(completionHandler)
+    }
+
+    // called by `stopTunnel` and `sleep`
+    func teardown(_ completionHandler: @escaping () -> Void) {
         guard let manager else {
-            logger.error("stopTunnel called with nil Manager")
+            logger.error("teardown called with nil Manager")
             completionHandler()
             return
         }
@@ -121,15 +131,25 @@ class PacketTunnelProvider: NEPacketTunnelProvider, @unchecked Sendable {
         }
     }
 
+    // sleep and wake reference: https://developer.apple.com/forums/thread/95988
     override func sleep(completionHandler: @escaping () -> Void) {
-        // Add code here to get ready to sleep.
         logger.debug("sleep called")
-        completionHandler()
+        teardown(completionHandler)
     }
 
     override func wake() {
-        // Add code here to wake up.
         logger.debug("wake called")
+        reasserting = true
+        currentSettings = .init(tunnelRemoteAddress: "127.0.0.1")
+        setTunnelNetworkSettings(nil)
+        start { error in
+            if let error {
+                self.logger.error("error starting tunnel after wake: \(error.localizedDescription)")
+                self.cancelTunnelWithError(error)
+            } else {
+                self.reasserting = false
+            }
+        }
     }
 
     // Wrapper around `setTunnelNetworkSettings` that supports merging updates

Coder Desktop/VPNLib/Download.swift

@@ -109,10 +109,14 @@ public func download(src: URL, dest: URL) async throws(DownloadError) {
         }
     }
     // TODO: Add Content-Length headers to coderd, add download progress delegate
+    let sessionConfig = URLSessionConfiguration.default
+    // The tunnel might be asked to start before the network interfaces have woken up from sleep
+    sessionConfig.waitsForConnectivity = true
+    let session = URLSession(configuration: sessionConfig)
     let tempURL: URL
     let response: URLResponse
     do {
-        (tempURL, response) = try await URLSession.shared.download(for: req)
+        (tempURL, response) = try await session.download(for: req)
     } catch {
         throw .networkError(error)
     }