coder · ethanndickson · Aug 6, 2025 · Jul 23, 2025 · Jul 31, 2025
diff --git a/Coder-Desktop/Coder-Desktop/AppHelperXPCClient.swift b/Coder-Desktop/Coder-Desktop/AppHelperXPCClient.swift
@@ -0,0 +1,102 @@
+import Foundation
+import NetworkExtension
+import os
+import VPNLib
+
+// This is the client for the app to communicate with the privileged helper.
+@objc final class HelperXPCClient: NSObject, @unchecked Sendable {
+    private var svc: CoderVPNService
+    private let logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "HelperXPCClient")
+    private var connection: NSXPCConnection?
+
+    init(vpn: CoderVPNService) {
+        svc = vpn
+        super.init()
+    }
+
+    func connect() -> NSXPCConnection {
+        if let connection {
+            return connection
+        }
+
+        let connection = NSXPCConnection(
+            machServiceName: helperAppMachServiceName,
+            options: .privileged
+        )
+        connection.remoteObjectInterface = NSXPCInterface(with: HelperAppXPCInterface.self)
+        connection.exportedInterface = NSXPCInterface(with: AppXPCInterface.self)
+        connection.exportedObject = self
+        connection.invalidationHandler = {
+            self.logger.error("XPC connection invalidated")
+            self.connection = nil
+            _ = self.connect()
+        }
+        connection.interruptionHandler = {
+            self.logger.error("XPC connection interrupted")
+            self.connection = nil
+            _ = self.connect()
+        }
+        logger.info("connecting to \(helperAppMachServiceName)")
+        connection.resume()
+        self.connection = connection
+        return connection
+    }
+
+    // Establishes a connection to the Helper, so it can send messages back.
+    func ping() async throws {
+        let conn = connect()
+        return try await withCheckedThrowingContinuation { continuation in
+            guard let proxy = conn.remoteObjectProxyWithErrorHandler({ err in
+                self.logger.error("failed to connect to HelperXPC \(err.localizedDescription, privacy: .public)")
+                continuation.resume(throwing: err)
+            }) as? HelperAppXPCInterface else {
+                self.logger.error("failed to get proxy for HelperXPC")
+                continuation.resume(throwing: XPCError.wrongProxyType)
+                return
+            }
+            proxy.ping {
+                self.logger.info("Connected to Helper over XPC")
+                continuation.resume()
+            }
+        }
+    }
+
+    func getPeerState() async throws {
+        let conn = connect()
+        return try await withCheckedThrowingContinuation { continuation in
+            guard let proxy = conn.remoteObjectProxyWithErrorHandler({ err in
+                self.logger.error("failed to connect to HelperXPC \(err.localizedDescription, privacy: .public)")
+                continuation.resume(throwing: err)
+            }) as? HelperAppXPCInterface else {
+                self.logger.error("failed to get proxy for HelperXPC")
+                continuation.resume(throwing: XPCError.wrongProxyType)
+                return
+            }
+            proxy.getPeerState { data in
+                Task { @MainActor in
+                    self.svc.onExtensionPeerState(data)
+                }
+                continuation.resume()
+            }
+        }
+    }
+}
+
+// These methods are called by the Helper over XPC
+extension HelperXPCClient: AppXPCInterface {
+    func onPeerUpdate(_ diff: Data, reply: @escaping () -> Void) {
+        let reply = CompletionWrapper(reply)
+        Task { @MainActor in
+            svc.onExtensionPeerUpdate(diff)
+            reply()
+        }
+    }
+
+    func onProgress(stage: ProgressStage, downloadProgress: DownloadProgress?, reply: @escaping () -> Void) {
+        let reply = CompletionWrapper(reply)
+        Task { @MainActor in
+            svc.onProgress(stage: stage, downloadProgress: downloadProgress)
+            reply()
+        }
+    }
+}
diff --git a/Coder-Desktop/Coder-Desktop/VPN/VPNService.swift b/Coder-Desktop/Coder-Desktop/VPN/VPNService.swift
@@ -54,7 +54,7 @@ enum VPNServiceError: Error, Equatable {
 @MainActor
 final class CoderVPNService: NSObject, VPNService {
     var logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "vpn")
-    lazy var xpc: VPNXPCInterface = .init(vpn: self)
+    lazy var xpc: HelperXPCClient = .init(vpn: self)
 
     @Published var tunnelState: VPNServiceState = .disabled {
         didSet {
@@ -138,10 +138,10 @@ final class CoderVPNService: NSObject, VPNService {
         }
     }
 
-    func onExtensionPeerUpdate(_ data: Data) {
+    func onExtensionPeerUpdate(_ diff: Data) {
         logger.info("network extension peer update")
         do {
-            let msg = try Vpn_PeerUpdate(serializedBytes: data)
+            let msg = try Vpn_PeerUpdate(serializedBytes: diff)
             debugPrint(msg)
             applyPeerUpdate(with: msg)
         } catch {
@@ -199,16 +199,18 @@ extension CoderVPNService {
             break
         // Non-connecting -> Connecting: Establish XPC
         case (_, .connecting):
-            xpc.connect()
-            xpc.ping()
+            // Detached to run ASAP
+            // TODO: Switch to `Task.immediate` once stable
+            Task.detached { try? await self.xpc.ping() }
             tunnelState = .connecting
         // Non-connected -> Connected:
         // - Retrieve Peers
         // - Run `onStart` closure
         case (_, .connected):
             onStart?()
-            xpc.connect()
-            xpc.getPeerState()
+            // Detached to run ASAP
+            // TODO: Switch to `Task.immediate` once stable
+            Task.detached { try? await self.xpc.getPeerState() }
             tunnelState = .connected
         // Any -> Reasserting
         case (_, .reasserting):

diff --git a/Coder-Desktop/Coder-Desktop/Views/LoginForm.swift b/Coder-Desktop/Coder-Desktop/Views/LoginForm.swift
@@ -90,7 +90,7 @@ struct LoginForm: View {
             return
         }
         // x.compare(y) is .orderedDescending if x > y
-        guard SignatureValidator.minimumCoderVersion.compare(semver, options: .numeric) != .orderedDescending else {
+        guard Validator.minimumCoderVersion.compare(semver, options: .numeric) != .orderedDescending else {
             loginError = .outdatedCoderVersion
             return
         }
@@ -192,13 +192,13 @@ struct LoginForm: View {
 @discardableResult
 func validateURL(_ url: String) throws(LoginError) -> URL {
     guard let url = URL(string: url) else {
-        throw LoginError.invalidURL
+        throw .invalidURL
     }
     guard url.scheme == "https" else {
-        throw LoginError.httpsRequired
+        throw .httpsRequired
     }
     guard url.host != nil else {
-        throw LoginError.noHost
+        throw .noHost
     }
     return url
 }
@@ -221,7 +221,7 @@ enum LoginError: Error {
             "Invalid URL"
         case .outdatedCoderVersion:
             """
-            The Coder deployment must be version \(SignatureValidator.minimumCoderVersion)
+            The Coder deployment must be version \(Validator.minimumCoderVersion)
             or higher to use Coder Desktop.
             """
         case let .failedAuth(err):

diff --git a/Coder-Desktop/Coder-Desktop/XPCInterface.swift b/Coder-Desktop/Coder-Desktop/XPCInterface.swift