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Hi, I have been working on some kind of network filtering app for iOS using Content Filter Provider. And I have stored rules for each domain. As of right now, I use UserDefaults with my app's bundle suite to store and observe rules. I have also read this documentation page for UserDefaults link. Is it okay to use UserDefaults in my case, if I have rules added/modified dynamically as the flow is intercepted, or should I pick some other approach like Core Data, SwiftData, etc.? Thank you!

On the [documentation page](Implement a completely custom DNS proxying protocol) it says For example, a DNS proxy provider might: Implement a completely custom DNS proxying protocol I would like to add some filtering logic to the NEDNSProxyProvider (for example, return nxdomain if the flow is not passing the filtering process). Is it possible to implement with NEDNSProxyProvider? It also says that func handleNewFlow(_ flow: NEAppProxyFlow) -> Bool from NEDNSProxyProvider returns a Boolean value set to true if the proxy implementation decides to handle the flow, or false if it instead decides to terminate the flow link. Does it mean that the filtering logic could be added here by just returning false for the flows that are not matching the rules? Because I first tried to handle UDP flows like this in handleNewFlow(_ flow: NEAppProxyUDPFlow) function and form my own packets in connection.transferData, by first passing empty Data object and then by setting RCODE to 3, which is supposedly a nxdomain response code. However, both implementations didn't work: even though I was getting logs about handling failure, the flow was still able to go through. try await flow.open(withLocalEndpoint: flow.localEndpoint as? NWHostEndpoint) let datagrams = try await flow.readDatagrams() let results = try await datagrams.parallelMap { let connection = try DatagramConnection($0) return try await connection.transferData() } try await flow.writeDatagrams(results) flow.closeReadWithError(nil) flow.closeWriteWithError(nil) I am new to NEDNSProxyProvider and my networking knowledge is on a pretty basic level, so I would be very grateful to hear any suggestions. Thank you!

Hi, I was working on some new filtering logic for my Content Filter that I would like to add. It involves making requests to remote DNS resolvers. Is it possible to use it within sync override func handleNewFlow(_ flow: NEFilterFlow) -> NEFilterNewFlowVerdict of the NEFilterDataProvider? As of right now, I have a concept working in Command Line Tool and playground, however, when I try to add working module to the main project, it's not working (connections are not loading). Function that makes requests to the servers: In this function I use DispatchGroup and notify for non-main queue @available(iOS 12, *) public class NetworkService { private let nonMainQueue: DispatchQueue = DispatchQueue(label: "non-main-queue") func isBlocked(hostname: String, completion: @escaping (Bool) -> Void) { var isAnyBlocked = false let group = DispatchGroup() for server in servers { group.enter() let endpoint = NWEndpoint.Host(server) query(host: endpoint, domain: hostname, queue: .global()) { response, error in defer { group.leave() } /* * some code that determines the filtering logic * if condition is true => isAnyBlocked = true & return */ } } group.notify(queue: nonMainQueue) { completion(isAnyBlocked) } } } And, for example, in playground Semaphores make it work as expected, but the same approach doesn't work with the NEFilterDataProvider playground code sample let hostname = "google.com" func returnResponse() -> String { var result = "" let semaphore = DispatchSemaphore(value: 0) DispatchQueue.global().async { NetworkService.isBlocked(hostname: hostname) { isBlocked in result = isBlocked ? "blocked" : "allowed" semaphore.signal() } } semaphore.wait() return result } print(returnResponse()) Output: allowed

Hi, I am working on the app for some basic concept, I would like to intercept both DNS and IP connections. I succeeded in intercepting DNS using NEDNSProxyProvider, however I seem to have some troubles with IPConnections using NEFilterDataProvider. First thing, I have three targets in my app. For some reason, when I run DNS Proxy Extension target it doesn't ask me to choose the app for target run, and after the application if launched, it correctly intercepts DNS traffic and inits NEDNSProxyManager ps: all logs are correctly displayed for NEFilterDataProvider However, when I try to run Filter Data Extension target with Content Filter capability, it asks me to choose the app for run. Even tho I checked the Build Settings and those are identical to DNS Proxy Extension target. And finally, when I run main target it still inits NEDNSProxyManager properly and the NEFilterManager returns this warning -[NEFilterManager saveToPreferencesWithCompletionHandler:]_block_invoke_3: failed to save the new configuration: (null) I tried to log the configuration and compared to some code samples, but I can't identify the problem. I'd very grateful if somebody could suggest where the problems might be (targets builds difference & NEFilterManager config) I will attach a sample of code where I add configuration to my NEFilterManager // MARK: - FilterDataManager final class FilterDataManager: NSObject, ObservableObject { // MARK: - Properties private let manager = NEFilterManager.shared() private let filterName = "Data Filter" @Published private(set) var isEnabled: Bool? = nil // MARK: - Singleton static let shared = FilterDataManager() // Cancellables set private var subs: Set<AnyCancellable> = [] private override init() { super.init() enable() manager.isEnabledPublisher() .receive(on: DispatchQueue.main) .sink(receiveValue: { [weak self] isEnabled in self?.setIsEnabled(isEnabled) }) .store(in: &subs) } // MARK: - Filter Configurations func enable() { manager.updateConfiguration { [unowned self] manager in manager.localizedDescription = filterName manager.providerConfiguration = createFilterProviderConfiguration() manager.isEnabled = true } completion: { result in guard case let .failure(error) = result else { return } Log("Filter enable failed: \(error)", prefix: "[Filter]") } } private func createFilterProviderConfiguration() -> NEFilterProviderConfiguration { let configuration = NEFilterProviderConfiguration() configuration.organization = "***" configuration.filterBrowsers = true configuration.filterSockets = true return configuration } func disable() { Log("Will disable filter", prefix: "[Filter]") manager.updateConfiguration { manager in manager.isEnabled = false } completion: { result in guard case let .failure(error) = result else { return } Log("Filter enable failed: \(error)") } } private func setIsEnabled(_ isEnabled: Bool) { guard self.isEnabled != isEnabled else { return } self.isEnabled = isEnabled Log("Filter \(isEnabled ? "enabled" : "disabled")", prefix: "[Filter]") } } ```Swift extension NEFilterManager { // MARK: - NEFilterManager config update func updateConfiguration(_ body: @escaping (NEFilterManager) -> Void, completion: @escaping (Result<Void, Error>) -> Void) { loadFromPreferences { [unowned self] error in if let error, let filterError = FilterError(error) { completion(.failure(filterError)) return } body(self) saveToPreferences { (error) in if let error, let filterError = FilterError(error) { completion(.failure(filterError)) return } completion(.success(())) } } } // MARK: - Publisher enabling func isEnabledPublisher() -> AnyPublisher<Bool, Never> { NotificationCenter.default .publisher(for: NSNotification.Name.NEFilterConfigurationDidChange) .compactMap { [weak self] notification in guard let self else { return nil } return self.isEnabled } .eraseToAnyPublisher() } } // MARK: - FilterError @available(iOS 8.0, *) enum FilterError: Error { /// The Filter configuration is invalid case configurationInvalid /// The Filter configuration is not enabled. case configurationDisabled /// The Filter configuration needs to be loaded. case configurationStale /// The Filter configuration cannot be removed. case configurationCannotBeRemoved /// Permission denied to modify the configuration case configurationPermissionDenied /// Internal error occurred while managing the configuration case configurationInternalError case unknown init?(_ error: Error) { switch error { case let error as NSError: switch NEFilterManagerError(rawValue: error.code) { case .configurationInvalid: self = .configurationInvalid return case .configurationDisabled: self = .configurationDisabled return case .configurationStale: self = .configurationStale return case .configurationCannotBeRemoved: self = .configurationCannotBeRemoved return case .some(.configurationPermissionDenied): self = .configurationPermissionDenied return case .some(.configurationInternalError): self = .configurationInternalError return case .none: return nil @unknown default: break } default: break } assertionFailure("Invalid error \(error)") return nil } }