Move all source files to `Sources/` and rename WireGuardKit targets

Signed-off-by: Andrej Mihajlov <and@mullvad.net>

6 files changed, 1344 insertions, 0 deletions

diff --git a/Sources/WireGuardApp/Tunnel/ActivateOnDemandOption.swift b/Sources/WireGuardApp/Tunnel/ActivateOnDemandOption.swift
new file mode 100644
index 0000000..d44e1d6
--- /dev/null
+++ b/Sources/WireGuardApp/Tunnel/ActivateOnDemandOption.swift
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
+
+import NetworkExtension
+
+enum ActivateOnDemandOption: Equatable {
+    case off
+    case wiFiInterfaceOnly(ActivateOnDemandSSIDOption)
+    case nonWiFiInterfaceOnly
+    case anyInterface(ActivateOnDemandSSIDOption)
+}
+
+#if os(iOS)
+private let nonWiFiInterfaceType: NEOnDemandRuleInterfaceType = .cellular
+#elseif os(macOS)
+private let nonWiFiInterfaceType: NEOnDemandRuleInterfaceType = .ethernet
+#else
+#error("Unimplemented")
+#endif
+
+enum ActivateOnDemandSSIDOption: Equatable {
+    case anySSID
+    case onlySpecificSSIDs([String])
+    case exceptSpecificSSIDs([String])
+}
+
+extension ActivateOnDemandOption {
+    func apply(on tunnelProviderManager: NETunnelProviderManager) {
+        let rules: [NEOnDemandRule]?
+        switch self {
+        case .off:
+            rules = nil
+        case .wiFiInterfaceOnly(let ssidOption):
+            rules = ssidOnDemandRules(option: ssidOption) + [NEOnDemandRuleDisconnect(interfaceType: nonWiFiInterfaceType)]
+        case .nonWiFiInterfaceOnly:
+            rules = [NEOnDemandRuleConnect(interfaceType: nonWiFiInterfaceType), NEOnDemandRuleDisconnect(interfaceType: .wiFi)]
+        case .anyInterface(let ssidOption):
+            if case .anySSID = ssidOption {
+                rules = [NEOnDemandRuleConnect(interfaceType: .any)]
+            } else {
+                rules = ssidOnDemandRules(option: ssidOption) + [NEOnDemandRuleConnect(interfaceType: nonWiFiInterfaceType)]
+            }
+        }
+        tunnelProviderManager.onDemandRules = rules
+        tunnelProviderManager.isOnDemandEnabled = self != .off
+    }
+
+    init(from tunnelProviderManager: NETunnelProviderManager) {
+        if tunnelProviderManager.isOnDemandEnabled, let onDemandRules = tunnelProviderManager.onDemandRules {
+            self = ActivateOnDemandOption.create(from: onDemandRules)
+        } else {
+            self = .off
+        }
+    }
+
+    private static func create(from rules: [NEOnDemandRule]) -> ActivateOnDemandOption {
+        switch rules.count {
+        case 0:
+            return .off
+        case 1:
+            let rule = rules[0]
+            guard rule.action == .connect else { return .off }
+            return .anyInterface(.anySSID)
+        case 2:
+            guard let connectRule = rules.first(where: { $0.action == .connect }) else {
+                wg_log(.error, message: "Unexpected onDemandRules set on tunnel provider manager: \(rules.count) rules found but no connect rule.")
+                return .off
+            }
+            guard let disconnectRule = rules.first(where: { $0.action == .disconnect }) else {
+                wg_log(.error, message: "Unexpected onDemandRules set on tunnel provider manager: \(rules.count) rules found but no disconnect rule.")
+                return .off
+            }
+            if connectRule.interfaceTypeMatch == .wiFi && disconnectRule.interfaceTypeMatch == nonWiFiInterfaceType {
+                return .wiFiInterfaceOnly(.anySSID)
+            } else if connectRule.interfaceTypeMatch == nonWiFiInterfaceType && disconnectRule.interfaceTypeMatch == .wiFi {
+                return .nonWiFiInterfaceOnly
+            } else {
+                wg_log(.error, message: "Unexpected onDemandRules set on tunnel provider manager: \(rules.count) rules found but interface types are inconsistent.")
+                return .off
+            }
+        case 3:
+            guard let ssidRule = rules.first(where: { $0.interfaceTypeMatch == .wiFi && $0.ssidMatch != nil }) else { return .off }
+            guard let nonWiFiRule = rules.first(where: { $0.interfaceTypeMatch == nonWiFiInterfaceType }) else { return .off }
+            let ssids = ssidRule.ssidMatch!
+            switch (ssidRule.action, nonWiFiRule.action) {
+            case (.connect, .connect):
+                return .anyInterface(.onlySpecificSSIDs(ssids))
+            case (.connect, .disconnect):
+                return .wiFiInterfaceOnly(.onlySpecificSSIDs(ssids))
+            case (.disconnect, .connect):
+                return .anyInterface(.exceptSpecificSSIDs(ssids))
+            case (.disconnect, .disconnect):
+                return .wiFiInterfaceOnly(.exceptSpecificSSIDs(ssids))
+            default:
+                wg_log(.error, message: "Unexpected onDemandRules set on tunnel provider manager: \(rules.count) rules found")
+                return .off
+            }
+        default:
+            wg_log(.error, message: "Unexpected number of onDemandRules set on tunnel provider manager: \(rules.count) rules found")
+            return .off
+        }
+    }
+}
+
+private extension NEOnDemandRuleConnect {
+    convenience init(interfaceType: NEOnDemandRuleInterfaceType, ssids: [String]? = nil) {
+        self.init()
+        interfaceTypeMatch = interfaceType
+        ssidMatch = ssids
+    }
+}
+
+private extension NEOnDemandRuleDisconnect {
+    convenience init(interfaceType: NEOnDemandRuleInterfaceType, ssids: [String]? = nil) {
+        self.init()
+        interfaceTypeMatch = interfaceType
+        ssidMatch = ssids
+    }
+}
+
+private func ssidOnDemandRules(option: ActivateOnDemandSSIDOption) -> [NEOnDemandRule] {
+    switch option {
+    case .anySSID:
+        return [NEOnDemandRuleConnect(interfaceType: .wiFi)]
+    case .onlySpecificSSIDs(let ssids):
+        assert(!ssids.isEmpty)
+        return [NEOnDemandRuleConnect(interfaceType: .wiFi, ssids: ssids),
+                NEOnDemandRuleDisconnect(interfaceType: .wiFi)]
+    case .exceptSpecificSSIDs(let ssids):
+        return [NEOnDemandRuleDisconnect(interfaceType: .wiFi, ssids: ssids),
+                NEOnDemandRuleConnect(interfaceType: .wiFi)]
+    }
+}
diff --git a/Sources/WireGuardApp/Tunnel/MockTunnels.swift b/Sources/WireGuardApp/Tunnel/MockTunnels.swift
new file mode 100644
index 0000000..1ffa99c
--- /dev/null
+++ b/Sources/WireGuardApp/Tunnel/MockTunnels.swift
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
+
+import NetworkExtension
+import WireGuardKit
+
+// Creates mock tunnels for the iOS Simulator.
+
+#if targetEnvironment(simulator)
+class MockTunnels {
+    static let tunnelNames = [
+        "demo",
+        "edgesecurity",
+        "home",
+        "office",
+        "infra-fr",
+        "infra-us",
+        "krantz",
+        "metheny",
+        "frisell"
+    ]
+    static let address = "192.168.%d.%d/32"
+    static let dnsServers = ["8.8.8.8", "8.8.4.4"]
+    static let endpoint = "demo.wireguard.com:51820"
+    static let allowedIPs = "0.0.0.0/0"
+
+    static func createMockTunnels() -> [NETunnelProviderManager] {
+        return tunnelNames.map { tunnelName -> NETunnelProviderManager in
+
+            var interface = InterfaceConfiguration(privateKey: PrivateKey())
+            interface.addresses = [IPAddressRange(from: String(format: address, Int.random(in: 1 ... 10), Int.random(in: 1 ... 254)))!]
+            interface.dns = dnsServers.map { DNSServer(from: $0)! }
+
+            var peer = PeerConfiguration(publicKey: PrivateKey().publicKey)
+            peer.endpoint = Endpoint(from: endpoint)
+            peer.allowedIPs = [IPAddressRange(from: allowedIPs)!]
+
+            let tunnelConfiguration = TunnelConfiguration(name: tunnelName, interface: interface, peers: [peer])
+
+            let tunnelProviderManager = NETunnelProviderManager()
+            tunnelProviderManager.protocolConfiguration = NETunnelProviderProtocol(tunnelConfiguration: tunnelConfiguration)
+            tunnelProviderManager.localizedDescription = tunnelConfiguration.name
+            tunnelProviderManager.isEnabled = true
+
+            return tunnelProviderManager
+        }
+    }
+}
+#endif
diff --git a/Sources/WireGuardApp/Tunnel/TunnelConfiguration+UapiConfig.swift b/Sources/WireGuardApp/Tunnel/TunnelConfiguration+UapiConfig.swift
new file mode 100644
index 0000000..fcd6a31
--- /dev/null
+++ b/Sources/WireGuardApp/Tunnel/TunnelConfiguration+UapiConfig.swift
@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import WireGuardKit
+
+extension TunnelConfiguration {
+    convenience init(fromUapiConfig uapiConfig: String, basedOn base: TunnelConfiguration? = nil) throws {
+        var interfaceConfiguration: InterfaceConfiguration?
+        var peerConfigurations = [PeerConfiguration]()
+
+        var lines = uapiConfig.split(separator: "\n")
+        lines.append("")
+
+        var parserState = ParserState.inInterfaceSection
+        var attributes = [String: String]()
+
+        for line in lines {
+            var key = ""
+            var value = ""
+
+            if !line.isEmpty {
+                guard let equalsIndex = line.firstIndex(of: "=") else { throw ParseError.invalidLine(line) }
+                key = String(line[..<equalsIndex])
+                value = String(line[line.index(equalsIndex, offsetBy: 1)...])
+            }
+
+            if line.isEmpty || key == "public_key" {
+                // Previous section has ended; process the attributes collected so far
+                if parserState == .inInterfaceSection {
+                    let interface = try TunnelConfiguration.collate(interfaceAttributes: attributes)
+                    guard interfaceConfiguration == nil else { throw ParseError.multipleInterfaces }
+                    interfaceConfiguration = interface
+                    parserState = .inPeerSection
+                } else if parserState == .inPeerSection {
+                    let peer = try TunnelConfiguration.collate(peerAttributes: attributes)
+                    peerConfigurations.append(peer)
+                }
+                attributes.removeAll()
+                if line.isEmpty {
+                    break
+                }
+            }
+
+            if let presentValue = attributes[key] {
+                if key == "allowed_ip" {
+                    attributes[key] = presentValue + "," + value
+                } else {
+                    throw ParseError.multipleEntriesForKey(key)
+                }
+            } else {
+                attributes[key] = value
+            }
+
+            let interfaceSectionKeys: Set<String> = ["private_key", "listen_port", "fwmark"]
+            let peerSectionKeys: Set<String> = ["public_key", "preshared_key", "allowed_ip", "endpoint", "persistent_keepalive_interval", "last_handshake_time_sec", "last_handshake_time_nsec", "rx_bytes", "tx_bytes", "protocol_version"]
+
+            if parserState == .inInterfaceSection {
+                guard interfaceSectionKeys.contains(key) else {
+                    throw ParseError.interfaceHasUnrecognizedKey(key)
+                }
+            }
+            if parserState == .inPeerSection {
+                guard peerSectionKeys.contains(key) else {
+                    throw ParseError.peerHasUnrecognizedKey(key)
+                }
+            }
+        }
+
+        let peerPublicKeysArray = peerConfigurations.map { $0.publicKey }
+        let peerPublicKeysSet = Set<PublicKey>(peerPublicKeysArray)
+        if peerPublicKeysArray.count != peerPublicKeysSet.count {
+            throw ParseError.multiplePeersWithSamePublicKey
+        }
+
+        interfaceConfiguration?.addresses = base?.interface.addresses ?? []
+        interfaceConfiguration?.dns = base?.interface.dns ?? []
+        interfaceConfiguration?.mtu = base?.interface.mtu
+
+        if let interfaceConfiguration = interfaceConfiguration {
+            self.init(name: base?.name, interface: interfaceConfiguration, peers: peerConfigurations)
+        } else {
+            throw ParseError.noInterface
+        }
+    }
+
+    private static func collate(interfaceAttributes attributes: [String: String]) throws -> InterfaceConfiguration {
+        guard let privateKeyString = attributes["private_key"] else {
+            throw ParseError.interfaceHasNoPrivateKey
+        }
+        guard let privateKey = PrivateKey(hexKey: privateKeyString) else {
+            throw ParseError.interfaceHasInvalidPrivateKey(privateKeyString)
+        }
+        var interface = InterfaceConfiguration(privateKey: privateKey)
+        if let listenPortString = attributes["listen_port"] {
+            guard let listenPort = UInt16(listenPortString) else {
+                throw ParseError.interfaceHasInvalidListenPort(listenPortString)
+            }
+            if listenPort != 0 {
+                interface.listenPort = listenPort
+            }
+        }
+        return interface
+    }
+
+    private static func collate(peerAttributes attributes: [String: String]) throws -> PeerConfiguration {
+        guard let publicKeyString = attributes["public_key"] else {
+            throw ParseError.peerHasNoPublicKey
+        }
+        guard let publicKey = PublicKey(hexKey: publicKeyString) else {
+            throw ParseError.peerHasInvalidPublicKey(publicKeyString)
+        }
+        var peer = PeerConfiguration(publicKey: publicKey)
+        if let preSharedKeyString = attributes["preshared_key"] {
+            guard let preSharedKey = PreSharedKey(hexKey: preSharedKeyString) else {
+                throw ParseError.peerHasInvalidPreSharedKey(preSharedKeyString)
+            }
+            // TODO(zx2c4): does the compiler optimize this away?
+            var accumulator: UInt8 = 0
+            for index in 0..<preSharedKey.rawValue.count {
+                accumulator |= preSharedKey.rawValue[index]
+            }
+            if accumulator != 0 {
+                peer.preSharedKey = preSharedKey
+            }
+        }
+        if let allowedIPsString = attributes["allowed_ip"] {
+            var allowedIPs = [IPAddressRange]()
+            for allowedIPString in allowedIPsString.splitToArray(trimmingCharacters: .whitespacesAndNewlines) {
+                guard let allowedIP = IPAddressRange(from: allowedIPString) else {
+                    throw ParseError.peerHasInvalidAllowedIP(allowedIPString)
+                }
+                allowedIPs.append(allowedIP)
+            }
+            peer.allowedIPs = allowedIPs
+        }
+        if let endpointString = attributes["endpoint"] {
+            guard let endpoint = Endpoint(from: endpointString) else {
+                throw ParseError.peerHasInvalidEndpoint(endpointString)
+            }
+            peer.endpoint = endpoint
+        }
+        if let persistentKeepAliveString = attributes["persistent_keepalive_interval"] {
+            guard let persistentKeepAlive = UInt16(persistentKeepAliveString) else {
+                throw ParseError.peerHasInvalidPersistentKeepAlive(persistentKeepAliveString)
+            }
+            if persistentKeepAlive != 0 {
+                peer.persistentKeepAlive = persistentKeepAlive
+            }
+        }
+        if let rxBytesString = attributes["rx_bytes"] {
+            guard let rxBytes = UInt64(rxBytesString) else {
+                throw ParseError.peerHasInvalidTransferBytes(rxBytesString)
+            }
+            if rxBytes != 0 {
+                peer.rxBytes = rxBytes
+            }
+        }
+        if let txBytesString = attributes["tx_bytes"] {
+            guard let txBytes = UInt64(txBytesString) else {
+                throw ParseError.peerHasInvalidTransferBytes(txBytesString)
+            }
+            if txBytes != 0 {
+                peer.txBytes = txBytes
+            }
+        }
+        if let lastHandshakeTimeSecString = attributes["last_handshake_time_sec"] {
+            var lastHandshakeTimeSince1970: TimeInterval = 0
+            guard let lastHandshakeTimeSec = UInt64(lastHandshakeTimeSecString) else {
+                throw ParseError.peerHasInvalidLastHandshakeTime(lastHandshakeTimeSecString)
+            }
+            if lastHandshakeTimeSec != 0 {
+                lastHandshakeTimeSince1970 += Double(lastHandshakeTimeSec)
+                if let lastHandshakeTimeNsecString = attributes["last_handshake_time_nsec"] {
+                    guard let lastHandshakeTimeNsec = UInt64(lastHandshakeTimeNsecString) else {
+                        throw ParseError.peerHasInvalidLastHandshakeTime(lastHandshakeTimeNsecString)
+                    }
+                    lastHandshakeTimeSince1970 += Double(lastHandshakeTimeNsec) / 1000000000.0
+                }
+                peer.lastHandshakeTime = Date(timeIntervalSince1970: lastHandshakeTimeSince1970)
+            }
+        }
+        return peer
+    }
+}
diff --git a/Sources/WireGuardApp/Tunnel/TunnelErrors.swift b/Sources/WireGuardApp/Tunnel/TunnelErrors.swift
new file mode 100644
index 0000000..941ab61
--- /dev/null
+++ b/Sources/WireGuardApp/Tunnel/TunnelErrors.swift
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
+
+import NetworkExtension
+
+enum TunnelsManagerError: WireGuardAppError {
+    case tunnelNameEmpty
+    case tunnelAlreadyExistsWithThatName
+    case systemErrorOnListingTunnels(systemError: Error)
+    case systemErrorOnAddTunnel(systemError: Error)
+    case systemErrorOnModifyTunnel(systemError: Error)
+    case systemErrorOnRemoveTunnel(systemError: Error)
+
+    var alertText: AlertText {
+        switch self {
+        case .tunnelNameEmpty:
+            return (tr("alertTunnelNameEmptyTitle"), tr("alertTunnelNameEmptyMessage"))
+        case .tunnelAlreadyExistsWithThatName:
+            return (tr("alertTunnelAlreadyExistsWithThatNameTitle"), tr("alertTunnelAlreadyExistsWithThatNameMessage"))
+        case .systemErrorOnListingTunnels(let systemError):
+            return (tr("alertSystemErrorOnListingTunnelsTitle"), systemError.localizedUIString)
+        case .systemErrorOnAddTunnel(let systemError):
+            return (tr("alertSystemErrorOnAddTunnelTitle"), systemError.localizedUIString)
+        case .systemErrorOnModifyTunnel(let systemError):
+            return (tr("alertSystemErrorOnModifyTunnelTitle"), systemError.localizedUIString)
+        case .systemErrorOnRemoveTunnel(let systemError):
+            return (tr("alertSystemErrorOnRemoveTunnelTitle"), systemError.localizedUIString)
+        }
+    }
+}
+
+enum TunnelsManagerActivationAttemptError: WireGuardAppError {
+    case tunnelIsNotInactive
+    case failedWhileStarting(systemError: Error) // startTunnel() throwed
+    case failedWhileSaving(systemError: Error) // save config after re-enabling throwed
+    case failedWhileLoading(systemError: Error) // reloading config throwed
+    case failedBecauseOfTooManyErrors(lastSystemError: Error) // recursion limit reached
+
+    var alertText: AlertText {
+        switch self {
+        case .tunnelIsNotInactive:
+            return (tr("alertTunnelActivationErrorTunnelIsNotInactiveTitle"), tr("alertTunnelActivationErrorTunnelIsNotInactiveMessage"))
+        case .failedWhileStarting(let systemError),
+             .failedWhileSaving(let systemError),
+             .failedWhileLoading(let systemError),
+             .failedBecauseOfTooManyErrors(let systemError):
+            return (tr("alertTunnelActivationSystemErrorTitle"),
+                    tr(format: "alertTunnelActivationSystemErrorMessage (%@)", systemError.localizedUIString))
+        }
+    }
+}
+
+enum TunnelsManagerActivationError: WireGuardAppError {
+    case activationFailed(wasOnDemandEnabled: Bool)
+    case activationFailedWithExtensionError(title: String, message: String, wasOnDemandEnabled: Bool)
+
+    var alertText: AlertText {
+        switch self {
+        case .activationFailed(let wasOnDemandEnabled):
+            return (tr("alertTunnelActivationFailureTitle"), tr("alertTunnelActivationFailureMessage") + (wasOnDemandEnabled ? tr("alertTunnelActivationFailureOnDemandAddendum") : ""))
+        case .activationFailedWithExtensionError(let title, let message, let wasOnDemandEnabled):
+            return (title, message + (wasOnDemandEnabled ? tr("alertTunnelActivationFailureOnDemandAddendum") : ""))
+        }
+    }
+}
+
+extension PacketTunnelProviderError: WireGuardAppError {
+    var alertText: AlertText {
+        switch self {
+        case .savedProtocolConfigurationIsInvalid:
+            return (tr("alertTunnelActivationFailureTitle"), tr("alertTunnelActivationSavedConfigFailureMessage"))
+        case .dnsResolutionFailure:
+            return (tr("alertTunnelDNSFailureTitle"), tr("alertTunnelDNSFailureMessage"))
+        case .couldNotStartBackend:
+            return (tr("alertTunnelActivationFailureTitle"), tr("alertTunnelActivationBackendFailureMessage"))
+        case .couldNotDetermineFileDescriptor:
+            return (tr("alertTunnelActivationFailureTitle"), tr("alertTunnelActivationFileDescriptorFailureMessage"))
+        case .couldNotSetNetworkSettings:
+            return (tr("alertTunnelActivationFailureTitle"), tr("alertTunnelActivationSetNetworkSettingsMessage"))
+        }
+    }
+}
+
+extension Error {
+    var localizedUIString: String {
+        if let systemError = self as? NEVPNError {
+            switch systemError {
+            case NEVPNError.configurationInvalid:
+                return tr("alertSystemErrorMessageTunnelConfigurationInvalid")
+            case NEVPNError.configurationDisabled:
+                return tr("alertSystemErrorMessageTunnelConfigurationDisabled")
+            case NEVPNError.connectionFailed:
+                return tr("alertSystemErrorMessageTunnelConnectionFailed")
+            case NEVPNError.configurationStale:
+                return tr("alertSystemErrorMessageTunnelConfigurationStale")
+            case NEVPNError.configurationReadWriteFailed:
+                return tr("alertSystemErrorMessageTunnelConfigurationReadWriteFailed")
+            case NEVPNError.configurationUnknown:
+                return tr("alertSystemErrorMessageTunnelConfigurationUnknown")
+            default:
+                return ""
+            }
+        } else {
+            return localizedDescription
+        }
+    }
+}
diff --git a/Sources/WireGuardApp/Tunnel/TunnelStatus.swift b/Sources/WireGuardApp/Tunnel/TunnelStatus.swift
new file mode 100644
index 0000000..547aa9f
--- /dev/null
+++ b/Sources/WireGuardApp/Tunnel/TunnelStatus.swift
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import NetworkExtension
+
+@objc enum TunnelStatus: Int {
+    case inactive
+    case activating
+    case active
+    case deactivating
+    case reasserting // Not a possible state at present
+    case restarting // Restarting tunnel (done after saving modifications to an active tunnel)
+    case waiting    // Waiting for another tunnel to be brought down
+
+    init(from systemStatus: NEVPNStatus) {
+        switch systemStatus {
+        case .connected:
+            self = .active
+        case .connecting:
+            self = .activating
+        case .disconnected:
+            self = .inactive
+        case .disconnecting:
+            self = .deactivating
+        case .reasserting:
+            self = .reasserting
+        case .invalid:
+            self = .inactive
+        @unknown default:
+            fatalError()
+        }
+    }
+}
+
+extension TunnelStatus: CustomDebugStringConvertible {
+    public var debugDescription: String {
+        switch self {
+        case .inactive: return "inactive"
+        case .activating: return "activating"
+        case .active: return "active"
+        case .deactivating: return "deactivating"
+        case .reasserting: return "reasserting"
+        case .restarting: return "restarting"
+        case .waiting: return "waiting"
+        }
+    }
+}
+
+extension NEVPNStatus: CustomDebugStringConvertible {
+    public var debugDescription: String {
+        switch self {
+        case .connected: return "connected"
+        case .connecting: return "connecting"
+        case .disconnected: return "disconnected"
+        case .disconnecting: return "disconnecting"
+        case .reasserting: return "reasserting"
+        case .invalid: return "invalid"
+        @unknown default:
+            fatalError()
+        }
+    }
+}
diff --git a/Sources/WireGuardApp/Tunnel/TunnelsManager.swift b/Sources/WireGuardApp/Tunnel/TunnelsManager.swift
new file mode 100644
index 0000000..af6a9bb
--- /dev/null
+++ b/Sources/WireGuardApp/Tunnel/TunnelsManager.swift
@@ -0,0 +1,807 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import NetworkExtension
+import os.log
+import WireGuardKit
+
+protocol TunnelsManagerListDelegate: class {
+    func tunnelAdded(at index: Int)
+    func tunnelModified(at index: Int)
+    func tunnelMoved(from oldIndex: Int, to newIndex: Int)
+    func tunnelRemoved(at index: Int, tunnel: TunnelContainer)
+}
+
+protocol TunnelsManagerActivationDelegate: class {
+    func tunnelActivationAttemptFailed(tunnel: TunnelContainer, error: TunnelsManagerActivationAttemptError) // startTunnel wasn't called or failed
+    func tunnelActivationAttemptSucceeded(tunnel: TunnelContainer) // startTunnel succeeded
+    func tunnelActivationFailed(tunnel: TunnelContainer, error: TunnelsManagerActivationError) // status didn't change to connected
+    func tunnelActivationSucceeded(tunnel: TunnelContainer) // status changed to connected
+}
+
+class TunnelsManager {
+    fileprivate var tunnels: [TunnelContainer]
+    weak var tunnelsListDelegate: TunnelsManagerListDelegate?
+    weak var activationDelegate: TunnelsManagerActivationDelegate?
+    private var statusObservationToken: AnyObject?
+    private var waiteeObservationToken: AnyObject?
+    private var configurationsObservationToken: AnyObject?
+    private var catalinaWorkaround: Any?
+
+    init(tunnelProviders: [NETunnelProviderManager]) {
+        tunnels = tunnelProviders.map { TunnelContainer(tunnel: $0) }.sorted { TunnelsManager.tunnelNameIsLessThan($0.name, $1.name) }
+        startObservingTunnelStatuses()
+        startObservingTunnelConfigurations()
+        #if os(macOS)
+        if #available(macOS 10.15, *) {
+            self.catalinaWorkaround = CatalinaWorkaround(tunnelsManager: self)
+        }
+        #endif
+    }
+
+    static func create(completionHandler: @escaping (Result<TunnelsManager, TunnelsManagerError>) -> Void) {
+        #if targetEnvironment(simulator)
+        completionHandler(.success(TunnelsManager(tunnelProviders: MockTunnels.createMockTunnels())))
+        #else
+        NETunnelProviderManager.loadAllFromPreferences { managers, error in
+            if let error = error {
+                wg_log(.error, message: "Failed to load tunnel provider managers: \(error)")
+                completionHandler(.failure(TunnelsManagerError.systemErrorOnListingTunnels(systemError: error)))
+                return
+            }
+
+            var tunnelManagers = managers ?? []
+            var refs: Set<Data> = []
+            var tunnelNames: Set<String> = []
+            for (index, tunnelManager) in tunnelManagers.enumerated().reversed() {
+                if let tunnelName = tunnelManager.localizedDescription {
+                    tunnelNames.insert(tunnelName)
+                }
+                guard let proto = tunnelManager.protocolConfiguration as? NETunnelProviderProtocol else { continue }
+                if proto.migrateConfigurationIfNeeded(called: tunnelManager.localizedDescription ?? "unknown") {
+                    tunnelManager.saveToPreferences { _ in }
+                }
+                #if os(iOS)
+                let passwordRef = proto.verifyConfigurationReference() ? proto.passwordReference : nil
+                #elseif os(macOS)
+                let passwordRef: Data?
+                if proto.providerConfiguration?["UID"] as? uid_t == getuid() {
+                    passwordRef = proto.verifyConfigurationReference() ? proto.passwordReference : nil
+                } else {
+                    passwordRef = proto.passwordReference // To handle multiple users in macOS, we skip verifying
+                }
+                #else
+                #error("Unimplemented")
+                #endif
+                if let ref = passwordRef {
+                    refs.insert(ref)
+                } else {
+                    wg_log(.info, message: "Removing orphaned tunnel with non-verifying keychain entry: \(tunnelManager.localizedDescription ?? "<unknown>")")
+                    tunnelManager.removeFromPreferences { _ in }
+                    tunnelManagers.remove(at: index)
+                }
+            }
+            #if os(macOS)
+            if #available(macOS 10.15, *) {
+                // Don't delete orphaned keychain refs. We need them to restore tunnels as a workaround.
+            } else {
+                Keychain.deleteReferences(except: refs)
+            }
+            #else
+            Keychain.deleteReferences(except: refs)
+            #endif
+            #if os(iOS)
+            RecentTunnelsTracker.cleanupTunnels(except: tunnelNames)
+            #endif
+            completionHandler(.success(TunnelsManager(tunnelProviders: tunnelManagers)))
+        }
+        #endif
+    }
+
+    func reload() {
+        NETunnelProviderManager.loadAllFromPreferences { [weak self] managers, _ in
+            guard let self = self else { return }
+
+            let loadedTunnelProviders = managers ?? []
+
+            for (index, currentTunnel) in self.tunnels.enumerated().reversed() {
+                if !loadedTunnelProviders.contains(where: { $0.isEquivalentTo(currentTunnel) }) {
+                    // Tunnel was deleted outside the app
+                    self.tunnels.remove(at: index)
+                    self.tunnelsListDelegate?.tunnelRemoved(at: index, tunnel: currentTunnel)
+                }
+            }
+            for loadedTunnelProvider in loadedTunnelProviders {
+                if let matchingTunnel = self.tunnels.first(where: { loadedTunnelProvider.isEquivalentTo($0) }) {
+                    matchingTunnel.tunnelProvider = loadedTunnelProvider
+                    matchingTunnel.refreshStatus()
+                } else {
+                    // Tunnel was added outside the app
+                    if let proto = loadedTunnelProvider.protocolConfiguration as? NETunnelProviderProtocol {
+                        if proto.migrateConfigurationIfNeeded(called: loadedTunnelProvider.localizedDescription ?? "unknown") {
+                            loadedTunnelProvider.saveToPreferences { _ in }
+                        }
+                    }
+                    let tunnel = TunnelContainer(tunnel: loadedTunnelProvider)
+                    self.tunnels.append(tunnel)
+                    self.tunnels.sort { TunnelsManager.tunnelNameIsLessThan($0.name, $1.name) }
+                    self.tunnelsListDelegate?.tunnelAdded(at: self.tunnels.firstIndex(of: tunnel)!)
+                }
+            }
+        }
+    }
+
+    func add(tunnelConfiguration: TunnelConfiguration, onDemandOption: ActivateOnDemandOption = .off, completionHandler: @escaping (Result<TunnelContainer, TunnelsManagerError>) -> Void) {
+        let tunnelName = tunnelConfiguration.name ?? ""
+        if tunnelName.isEmpty {
+            completionHandler(.failure(TunnelsManagerError.tunnelNameEmpty))
+            return
+        }
+
+        if tunnels.contains(where: { $0.name == tunnelName }) {
+            completionHandler(.failure(TunnelsManagerError.tunnelAlreadyExistsWithThatName))
+            return
+        }
+
+        let tunnelProviderManager = NETunnelProviderManager()
+        tunnelProviderManager.setTunnelConfiguration(tunnelConfiguration)
+        tunnelProviderManager.isEnabled = true
+
+        onDemandOption.apply(on: tunnelProviderManager)
+
+        let activeTunnel = tunnels.first { $0.status == .active || $0.status == .activating }
+
+        tunnelProviderManager.saveToPreferences { [weak self] error in
+            guard error == nil else {
+                wg_log(.error, message: "Add: Saving configuration failed: \(error!)")
+                (tunnelProviderManager.protocolConfiguration as? NETunnelProviderProtocol)?.destroyConfigurationReference()
+                completionHandler(.failure(TunnelsManagerError.systemErrorOnAddTunnel(systemError: error!)))
+                return
+            }
+
+            guard let self = self else { return }
+
+            #if os(iOS)
+            // HACK: In iOS, adding a tunnel causes deactivation of any currently active tunnel.
+            // This is an ugly hack to reactivate the tunnel that has been deactivated like that.
+            if let activeTunnel = activeTunnel {
+                if activeTunnel.status == .inactive || activeTunnel.status == .deactivating {
+                    self.startActivation(of: activeTunnel)
+                }
+                if activeTunnel.status == .active || activeTunnel.status == .activating {
+                    activeTunnel.status = .restarting
+                }
+            }
+            #endif
+
+            let tunnel = TunnelContainer(tunnel: tunnelProviderManager)
+            self.tunnels.append(tunnel)
+            self.tunnels.sort { TunnelsManager.tunnelNameIsLessThan($0.name, $1.name) }
+            self.tunnelsListDelegate?.tunnelAdded(at: self.tunnels.firstIndex(of: tunnel)!)
+            completionHandler(.success(tunnel))
+        }
+    }
+
+    func addMultiple(tunnelConfigurations: [TunnelConfiguration], completionHandler: @escaping (UInt, TunnelsManagerError?) -> Void) {
+        addMultiple(tunnelConfigurations: ArraySlice(tunnelConfigurations), numberSuccessful: 0, lastError: nil, completionHandler: completionHandler)
+    }
+
+    private func addMultiple(tunnelConfigurations: ArraySlice<TunnelConfiguration>, numberSuccessful: UInt, lastError: TunnelsManagerError?, completionHandler: @escaping (UInt, TunnelsManagerError?) -> Void) {
+        guard let head = tunnelConfigurations.first else {
+            completionHandler(numberSuccessful, lastError)
+            return
+        }
+        let tail = tunnelConfigurations.dropFirst()
+        add(tunnelConfiguration: head) { [weak self, tail] result in
+            DispatchQueue.main.async {
+                var numberSuccessfulCount = numberSuccessful
+                var lastError: TunnelsManagerError?
+                switch result {
+                case .failure(let error):
+                    lastError = error
+                case .success:
+                    numberSuccessfulCount = numberSuccessful + 1
+                }
+                self?.addMultiple(tunnelConfigurations: tail, numberSuccessful: numberSuccessfulCount, lastError: lastError, completionHandler: completionHandler)
+            }
+        }
+    }
+
+    func modify(tunnel: TunnelContainer, tunnelConfiguration: TunnelConfiguration, onDemandOption: ActivateOnDemandOption, completionHandler: @escaping (TunnelsManagerError?) -> Void) {
+        let tunnelName = tunnelConfiguration.name ?? ""
+        if tunnelName.isEmpty {
+            completionHandler(TunnelsManagerError.tunnelNameEmpty)
+            return
+        }
+
+        let tunnelProviderManager = tunnel.tunnelProvider
+        let oldName = tunnelProviderManager.localizedDescription ?? ""
+        let isNameChanged = tunnelName != oldName
+        if isNameChanged {
+            guard !tunnels.contains(where: { $0.name == tunnelName }) else {
+                completionHandler(TunnelsManagerError.tunnelAlreadyExistsWithThatName)
+                return
+            }
+            tunnel.name = tunnelName
+        }
+
+        var isTunnelConfigurationChanged = false
+        if tunnelProviderManager.tunnelConfiguration != tunnelConfiguration {
+            tunnelProviderManager.setTunnelConfiguration(tunnelConfiguration)
+            isTunnelConfigurationChanged = true
+        }
+        tunnelProviderManager.isEnabled = true
+
+        let isActivatingOnDemand = !tunnelProviderManager.isOnDemandEnabled && onDemandOption != .off
+        onDemandOption.apply(on: tunnelProviderManager)
+
+        tunnelProviderManager.saveToPreferences { [weak self] error in
+            guard error == nil else {
+                //TODO: the passwordReference for the old one has already been removed at this point and we can't easily roll back!
+                wg_log(.error, message: "Modify: Saving configuration failed: \(error!)")
+                completionHandler(TunnelsManagerError.systemErrorOnModifyTunnel(systemError: error!))
+                return
+            }
+            guard let self = self else { return }
+            if isNameChanged {
+                let oldIndex = self.tunnels.firstIndex(of: tunnel)!
+                self.tunnels.sort { TunnelsManager.tunnelNameIsLessThan($0.name, $1.name) }
+                let newIndex = self.tunnels.firstIndex(of: tunnel)!
+                self.tunnelsListDelegate?.tunnelMoved(from: oldIndex, to: newIndex)
+                #if os(iOS)
+                RecentTunnelsTracker.handleTunnelRenamed(oldName: oldName, newName: tunnelName)
+                #endif
+            }
+            self.tunnelsListDelegate?.tunnelModified(at: self.tunnels.firstIndex(of: tunnel)!)
+
+            if isTunnelConfigurationChanged {
+                if tunnel.status == .active || tunnel.status == .activating || tunnel.status == .reasserting {
+                    // Turn off the tunnel, and then turn it back on, so the changes are made effective
+                    tunnel.status = .restarting
+                    (tunnel.tunnelProvider.connection as? NETunnelProviderSession)?.stopTunnel()
+                }
+            }
+
+            if isActivatingOnDemand {
+                // Reload tunnel after saving.
+                // Without this, the tunnel stopes getting updates on the tunnel status from iOS.
+                tunnelProviderManager.loadFromPreferences { error in
+                    tunnel.isActivateOnDemandEnabled = tunnelProviderManager.isOnDemandEnabled
+                    guard error == nil else {
+                        wg_log(.error, message: "Modify: Re-loading after saving configuration failed: \(error!)")
+                        completionHandler(TunnelsManagerError.systemErrorOnModifyTunnel(systemError: error!))
+                        return
+                    }
+                    completionHandler(nil)
+                }
+            } else {
+                completionHandler(nil)
+            }
+        }
+    }
+
+    func remove(tunnel: TunnelContainer, completionHandler: @escaping (TunnelsManagerError?) -> Void) {
+        let tunnelProviderManager = tunnel.tunnelProvider
+        #if os(macOS)
+        if tunnel.isTunnelAvailableToUser {
+            (tunnelProviderManager.protocolConfiguration as? NETunnelProviderProtocol)?.destroyConfigurationReference()
+        }
+        #elseif os(iOS)
+        (tunnelProviderManager.protocolConfiguration as? NETunnelProviderProtocol)?.destroyConfigurationReference()
+        #else
+        #error("Unimplemented")
+        #endif
+        tunnelProviderManager.removeFromPreferences { [weak self] error in
+            guard error == nil else {
+                wg_log(.error, message: "Remove: Saving configuration failed: \(error!)")
+                completionHandler(TunnelsManagerError.systemErrorOnRemoveTunnel(systemError: error!))
+                return
+            }
+            if let self = self, let index = self.tunnels.firstIndex(of: tunnel) {
+                self.tunnels.remove(at: index)
+                self.tunnelsListDelegate?.tunnelRemoved(at: index, tunnel: tunnel)
+            }
+            completionHandler(nil)
+
+            #if os(iOS)
+            RecentTunnelsTracker.handleTunnelRemoved(tunnelName: tunnel.name)
+            #endif
+        }
+    }
+
+    func removeMultiple(tunnels: [TunnelContainer], completionHandler: @escaping (TunnelsManagerError?) -> Void) {
+        removeMultiple(tunnels: ArraySlice(tunnels), completionHandler: completionHandler)
+    }
+
+    private func removeMultiple(tunnels: ArraySlice<TunnelContainer>, completionHandler: @escaping (TunnelsManagerError?) -> Void) {
+        guard let head = tunnels.first else {
+            completionHandler(nil)
+            return
+        }
+        let tail = tunnels.dropFirst()
+        remove(tunnel: head) { [weak self, tail] error in
+            DispatchQueue.main.async {
+                if let error = error {
+                    completionHandler(error)
+                } else {
+                    self?.removeMultiple(tunnels: tail, completionHandler: completionHandler)
+                }
+            }
+        }
+    }
+
+    func numberOfTunnels() -> Int {
+        return tunnels.count
+    }
+
+    func tunnel(at index: Int) -> TunnelContainer {
+        return tunnels[index]
+    }
+
+    func mapTunnels<T>(transform: (TunnelContainer) throws -> T) rethrows -> [T] {
+        return try tunnels.map(transform)
+    }
+
+    func index(of tunnel: TunnelContainer) -> Int? {
+        return tunnels.firstIndex(of: tunnel)
+    }
+
+    func tunnel(named tunnelName: String) -> TunnelContainer? {
+        return tunnels.first { $0.name == tunnelName }
+    }
+
+    func waitingTunnel() -> TunnelContainer? {
+        return tunnels.first { $0.status == .waiting }
+    }
+
+    func tunnelInOperation() -> TunnelContainer? {
+        if let waitingTunnelObject = waitingTunnel() {
+            return waitingTunnelObject
+        }
+        return tunnels.first { $0.status != .inactive }
+    }
+
+    func startActivation(of tunnel: TunnelContainer) {
+        guard tunnels.contains(tunnel) else { return } // Ensure it's not deleted
+        guard tunnel.status == .inactive else {
+            activationDelegate?.tunnelActivationAttemptFailed(tunnel: tunnel, error: .tunnelIsNotInactive)
+            return
+        }
+
+        if let alreadyWaitingTunnel = tunnels.first(where: { $0.status == .waiting }) {
+            alreadyWaitingTunnel.status = .inactive
+        }
+
+        if let tunnelInOperation = tunnels.first(where: { $0.status != .inactive }) {
+            wg_log(.info, message: "Tunnel '\(tunnel.name)' waiting for deactivation of '\(tunnelInOperation.name)'")
+            tunnel.status = .waiting
+            activateWaitingTunnelOnDeactivation(of: tunnelInOperation)
+            if tunnelInOperation.status != .deactivating {
+                startDeactivation(of: tunnelInOperation)
+            }
+            return
+        }
+
+        #if targetEnvironment(simulator)
+        tunnel.status = .active
+        #else
+        tunnel.startActivation(activationDelegate: activationDelegate)
+        #endif
+
+        #if os(iOS)
+        RecentTunnelsTracker.handleTunnelActivated(tunnelName: tunnel.name)
+        #endif
+    }
+
+    func startDeactivation(of tunnel: TunnelContainer) {
+        tunnel.isAttemptingActivation = false
+        guard tunnel.status != .inactive && tunnel.status != .deactivating else { return }
+        #if targetEnvironment(simulator)
+        tunnel.status = .inactive
+        #else
+        tunnel.startDeactivation()
+        #endif
+    }
+
+    func refreshStatuses() {
+        tunnels.forEach { $0.refreshStatus() }
+    }
+
+    private func activateWaitingTunnelOnDeactivation(of tunnel: TunnelContainer) {
+        waiteeObservationToken = tunnel.observe(\.status) { [weak self] tunnel, _ in
+            guard let self = self else { return }
+            if tunnel.status == .inactive {
+                if let waitingTunnel = self.tunnels.first(where: { $0.status == .waiting }) {
+                    waitingTunnel.startActivation(activationDelegate: self.activationDelegate)
+                }
+                self.waiteeObservationToken = nil
+            }
+        }
+    }
+
+    private func startObservingTunnelStatuses() {
+        statusObservationToken = NotificationCenter.default.addObserver(forName: .NEVPNStatusDidChange, object: nil, queue: OperationQueue.main) { [weak self] statusChangeNotification in
+            guard let self = self,
+                let session = statusChangeNotification.object as? NETunnelProviderSession,
+                let tunnelProvider = session.manager as? NETunnelProviderManager,
+                let tunnel = self.tunnels.first(where: { $0.tunnelProvider == tunnelProvider }) else { return }
+
+            wg_log(.debug, message: "Tunnel '\(tunnel.name)' connection status changed to '\(tunnel.tunnelProvider.connection.status)'")
+
+            if tunnel.isAttemptingActivation {
+                if session.status == .connected {
+                    tunnel.isAttemptingActivation = false
+                    self.activationDelegate?.tunnelActivationSucceeded(tunnel: tunnel)
+                } else if session.status == .disconnected {
+                    tunnel.isAttemptingActivation = false
+                    if let (title, message) = lastErrorTextFromNetworkExtension(for: tunnel) {
+                        self.activationDelegate?.tunnelActivationFailed(tunnel: tunnel, error: .activationFailedWithExtensionError(title: title, message: message, wasOnDemandEnabled: tunnelProvider.isOnDemandEnabled))
+                    } else {
+                        self.activationDelegate?.tunnelActivationFailed(tunnel: tunnel, error: .activationFailed(wasOnDemandEnabled: tunnelProvider.isOnDemandEnabled))
+                    }
+                }
+            }
+
+            if tunnel.status == .restarting && session.status == .disconnected {
+                tunnel.startActivation(activationDelegate: self.activationDelegate)
+                return
+            }
+
+            tunnel.refreshStatus()
+        }
+    }
+
+    func startObservingTunnelConfigurations() {
+        configurationsObservationToken = NotificationCenter.default.addObserver(forName: .NEVPNConfigurationChange, object: nil, queue: OperationQueue.main) { [weak self] _ in
+            DispatchQueue.main.async { [weak self] in
+                // We schedule reload() in a subsequent runloop to ensure that the completion handler of loadAllFromPreferences
+                // (reload() calls loadAllFromPreferences) is called after the completion handler of the saveToPreferences or
+                // removeFromPreferences call, if any, that caused this notification to fire. This notification can also fire
+                // as a result of a tunnel getting added or removed outside of the app.
+                self?.reload()
+            }
+        }
+    }
+
+    static func tunnelNameIsLessThan(_ a: String, _ b: String) -> Bool {
+        return a.compare(b, options: [.caseInsensitive, .diacriticInsensitive, .widthInsensitive, .numeric]) == .orderedAscending
+    }
+}
+
+private func lastErrorTextFromNetworkExtension(for tunnel: TunnelContainer) -> (title: String, message: String)? {
+    guard let lastErrorFileURL = FileManager.networkExtensionLastErrorFileURL else { return nil }
+    guard let lastErrorData = try? Data(contentsOf: lastErrorFileURL) else { return nil }
+    guard let lastErrorStrings = String(data: lastErrorData, encoding: .utf8)?.splitToArray(separator: "\n") else { return nil }
+    guard lastErrorStrings.count == 2 && tunnel.activationAttemptId == lastErrorStrings[0] else { return nil }
+
+    if let extensionError = PacketTunnelProviderError(rawValue: lastErrorStrings[1]) {
+        return extensionError.alertText
+    }
+
+    return (tr("alertTunnelActivationFailureTitle"), tr("alertTunnelActivationFailureMessage"))
+}
+
+class TunnelContainer: NSObject {
+    @objc dynamic var name: String
+    @objc dynamic var status: TunnelStatus
+
+    @objc dynamic var isActivateOnDemandEnabled: Bool
+
+    var isAttemptingActivation = false {
+        didSet {
+            if isAttemptingActivation {
+                self.activationTimer?.invalidate()
+                let activationTimer = Timer(timeInterval: 5 /* seconds */, repeats: true) { [weak self] _ in
+                    guard let self = self else { return }
+                    wg_log(.debug, message: "Status update notification timeout for tunnel '\(self.name)'. Tunnel status is now '\(self.tunnelProvider.connection.status)'.")
+                    switch self.tunnelProvider.connection.status {
+                    case .connected, .disconnected, .invalid:
+                        self.activationTimer?.invalidate()
+                        self.activationTimer = nil
+                    default:
+                        break
+                    }
+                    self.refreshStatus()
+                }
+                self.activationTimer = activationTimer
+                RunLoop.main.add(activationTimer, forMode: .common)
+            }
+        }
+    }
+    var activationAttemptId: String?
+    var activationTimer: Timer?
+    var deactivationTimer: Timer?
+
+    fileprivate var tunnelProvider: NETunnelProviderManager
+
+    var tunnelConfiguration: TunnelConfiguration? {
+        return tunnelProvider.tunnelConfiguration
+    }
+
+    var onDemandOption: ActivateOnDemandOption {
+        return ActivateOnDemandOption(from: tunnelProvider)
+    }
+
+    #if os(macOS)
+    var isTunnelAvailableToUser: Bool {
+        return (tunnelProvider.protocolConfiguration as? NETunnelProviderProtocol)?.providerConfiguration?["UID"] as? uid_t == getuid()
+    }
+    #endif
+
+    init(tunnel: NETunnelProviderManager) {
+        name = tunnel.localizedDescription ?? "Unnamed"
+        let status = TunnelStatus(from: tunnel.connection.status)
+        self.status = status
+        isActivateOnDemandEnabled = tunnel.isOnDemandEnabled
+        tunnelProvider = tunnel
+        super.init()
+    }
+
+    func getRuntimeTunnelConfiguration(completionHandler: @escaping ((TunnelConfiguration?) -> Void)) {
+        guard status != .inactive, let session = tunnelProvider.connection as? NETunnelProviderSession else {
+            completionHandler(tunnelConfiguration)
+            return
+        }
+        guard nil != (try? session.sendProviderMessage(Data([ UInt8(0) ]), responseHandler: {
+            guard self.status != .inactive, let data = $0, let base = self.tunnelConfiguration, let settings = String(data: data, encoding: .utf8) else {
+                completionHandler(self.tunnelConfiguration)
+                return
+            }
+            completionHandler((try? TunnelConfiguration(fromUapiConfig: settings, basedOn: base)) ?? self.tunnelConfiguration)
+        })) else {
+            completionHandler(tunnelConfiguration)
+            return
+        }
+    }
+
+    func refreshStatus() {
+        if status == .restarting {
+            return
+        }
+        status = TunnelStatus(from: tunnelProvider.connection.status)
+        isActivateOnDemandEnabled = tunnelProvider.isOnDemandEnabled
+    }
+
+    fileprivate func startActivation(recursionCount: UInt = 0, lastError: Error? = nil, activationDelegate: TunnelsManagerActivationDelegate?) {
+        if recursionCount >= 8 {
+            wg_log(.error, message: "startActivation: Failed after 8 attempts. Giving up with \(lastError!)")
+            activationDelegate?.tunnelActivationAttemptFailed(tunnel: self, error: .failedBecauseOfTooManyErrors(lastSystemError: lastError!))
+            return
+        }
+
+        wg_log(.debug, message: "startActivation: Entering (tunnel: \(name))")
+
+        status = .activating // Ensure that no other tunnel can attempt activation until this tunnel is done trying
+
+        guard tunnelProvider.isEnabled else {
+            // In case the tunnel had gotten disabled, re-enable and save it,
+            // then call this function again.
+            wg_log(.debug, staticMessage: "startActivation: Tunnel is disabled. Re-enabling and saving")
+            tunnelProvider.isEnabled = true
+            tunnelProvider.saveToPreferences { [weak self] error in
+                guard let self = self else { return }
+                if error != nil {
+                    wg_log(.error, message: "Error saving tunnel after re-enabling: \(error!)")
+                    activationDelegate?.tunnelActivationAttemptFailed(tunnel: self, error: .failedWhileSaving(systemError: error!))
+                    return
+                }
+                wg_log(.debug, staticMessage: "startActivation: Tunnel saved after re-enabling, invoking startActivation")
+                self.startActivation(recursionCount: recursionCount + 1, lastError: NEVPNError(NEVPNError.configurationUnknown), activationDelegate: activationDelegate)
+            }
+            return
+        }
+
+        // Start the tunnel
+        do {
+            wg_log(.debug, staticMessage: "startActivation: Starting tunnel")
+            isAttemptingActivation = true
+            let activationAttemptId = UUID().uuidString
+            self.activationAttemptId = activationAttemptId
+            try (tunnelProvider.connection as? NETunnelProviderSession)?.startTunnel(options: ["activationAttemptId": activationAttemptId])
+            wg_log(.debug, staticMessage: "startActivation: Success")
+            activationDelegate?.tunnelActivationAttemptSucceeded(tunnel: self)
+        } catch let error {
+            isAttemptingActivation = false
+            guard let systemError = error as? NEVPNError else {
+                wg_log(.error, message: "Failed to activate tunnel: Error: \(error)")
+                status = .inactive
+                activationDelegate?.tunnelActivationAttemptFailed(tunnel: self, error: .failedWhileStarting(systemError: error))
+                return
+            }
+            guard systemError.code == NEVPNError.configurationInvalid || systemError.code == NEVPNError.configurationStale else {
+                wg_log(.error, message: "Failed to activate tunnel: VPN Error: \(error)")
+                status = .inactive
+                activationDelegate?.tunnelActivationAttemptFailed(tunnel: self, error: .failedWhileStarting(systemError: systemError))
+                return
+            }
+            wg_log(.debug, staticMessage: "startActivation: Will reload tunnel and then try to start it.")
+            tunnelProvider.loadFromPreferences { [weak self] error in
+                guard let self = self else { return }
+                if error != nil {
+                    wg_log(.error, message: "startActivation: Error reloading tunnel: \(error!)")
+                    self.status = .inactive
+                    activationDelegate?.tunnelActivationAttemptFailed(tunnel: self, error: .failedWhileLoading(systemError: systemError))
+                    return
+                }
+                wg_log(.debug, staticMessage: "startActivation: Tunnel reloaded, invoking startActivation")
+                self.startActivation(recursionCount: recursionCount + 1, lastError: systemError, activationDelegate: activationDelegate)
+            }
+        }
+    }
+
+    fileprivate func startDeactivation() {
+        wg_log(.debug, message: "startDeactivation: Tunnel: \(name)")
+        (tunnelProvider.connection as? NETunnelProviderSession)?.stopTunnel()
+    }
+}
+
+extension NETunnelProviderManager {
+    fileprivate static var cachedConfigKey: UInt8 = 0
+
+    var tunnelConfiguration: TunnelConfiguration? {
+        if let cached = objc_getAssociatedObject(self, &NETunnelProviderManager.cachedConfigKey) as? TunnelConfiguration {
+            return cached
+        }
+        let config = (protocolConfiguration as? NETunnelProviderProtocol)?.asTunnelConfiguration(called: localizedDescription)
+        if config != nil {
+            objc_setAssociatedObject(self, &NETunnelProviderManager.cachedConfigKey, config, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
+        }
+        return config
+    }
+
+    func setTunnelConfiguration(_ tunnelConfiguration: TunnelConfiguration) {
+        protocolConfiguration = NETunnelProviderProtocol(tunnelConfiguration: tunnelConfiguration, previouslyFrom: protocolConfiguration)
+        localizedDescription = tunnelConfiguration.name
+        objc_setAssociatedObject(self, &NETunnelProviderManager.cachedConfigKey, tunnelConfiguration, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
+    }
+
+    func isEquivalentTo(_ tunnel: TunnelContainer) -> Bool {
+        return localizedDescription == tunnel.name && tunnelConfiguration == tunnel.tunnelConfiguration
+    }
+}
+
+#if os(macOS)
+@available(macOS 10.15, *)
+class CatalinaWorkaround {
+
+    // In macOS Catalina, for some users, the tunnels get deleted arbitrarily
+    // by the OS. It's not clear what triggers that.
+
+    // As a workaround, in macOS Catalina, when we realize that tunnels have been
+    // deleted outside the app, we reinstate those tunnels using the information
+    // in the keychain.
+
+    unowned let tunnelsManager: TunnelsManager
+    private var configChangeSubscriber: Any?
+
+    struct ReinstationData {
+        let tunnelConfiguration: TunnelConfiguration
+        let keychainPasswordRef: Data
+    }
+
+    init(tunnelsManager: TunnelsManager) {
+        self.tunnelsManager = tunnelsManager
+
+        // Attempt reinstation when there's a change in tunnel configurations,
+        // which indicates that tunnels may have been deleted outside the app.
+        // We use debounce to wait for all change notifications to arrive
+        // before attempting to reinstate, so that we don't have saveToPreferences
+        // being called while another saveToPreferences is in progress.
+        self.configChangeSubscriber = NotificationCenter.default
+            .publisher(for: .NEVPNConfigurationChange, object: nil)
+            .debounce(for: .seconds(1), scheduler: RunLoop.main)
+            .subscribe(on: RunLoop.main)
+            .sink { [weak self] _ in
+                self?.reinstateTunnelsDeletedOutsideApp()
+        }
+
+        // Attempt reinstation on app launch
+        reinstateTunnelsDeletedOutsideApp()
+    }
+
+    func reinstateTunnelsDeletedOutsideApp() {
+        let rd = reinstationDataForTunnelsDeletedOutsideApp()
+        reinstateTunnels(ArraySlice(rd), completionHandler: nil)
+    }
+
+    private func reinstateTunnels(_ rdArray: ArraySlice<ReinstationData>, completionHandler: (() -> Void)?) {
+        guard let head = rdArray.first else {
+            completionHandler?()
+            return
+        }
+        let tail = rdArray.dropFirst()
+        self.tunnelsManager.reinstateTunnel(reinstationData: head) { _ in
+            DispatchQueue.main.async {
+                self.reinstateTunnels(tail, completionHandler: completionHandler)
+            }
+        }
+    }
+
+    private func reinstationDataForTunnelsDeletedOutsideApp() -> [ReinstationData] {
+        let knownRefs: [Data] = self.tunnelsManager.tunnels
+            .compactMap { $0.tunnelProvider.protocolConfiguration as? NETunnelProviderProtocol }
+            .compactMap { $0.passwordReference }
+        let knownRefsSet: Set<Data> = Set(knownRefs)
+        var result: CFTypeRef?
+        let ret = SecItemCopyMatching([kSecClass as String: kSecClassGenericPassword,
+                                       kSecAttrService as String: Bundle.main.bundleIdentifier as Any,
+                                       kSecMatchLimit as String: kSecMatchLimitAll,
+                                       kSecReturnAttributes as String: true,
+                                       kSecReturnPersistentRef as String: true] as CFDictionary,
+                                      &result)
+        guard ret == errSecSuccess, let resultDicts = result as? [[String: Any]] else { return [] }
+        let labelPrefix = "WireGuard Tunnel: "
+        var reinstationData: [ReinstationData] = []
+        for resultDict in resultDicts {
+            guard let ref = resultDict[kSecValuePersistentRef as String] as? Data else { continue }
+            guard let label = resultDict[kSecAttrLabel as String] as? String else { continue }
+            guard label.hasPrefix(labelPrefix) else { continue }
+            if !knownRefsSet.contains(ref) {
+                let tunnelName = String(label.dropFirst(labelPrefix.count))
+                if let configStr = Keychain.openReference(called: ref),
+                    let config = try? TunnelConfiguration(fromWgQuickConfig: configStr, called: tunnelName) {
+                    reinstationData.append(ReinstationData(tunnelConfiguration: config, keychainPasswordRef: ref))
+                }
+            }
+        }
+        return reinstationData
+    }
+}
+#endif
+
+#if os(macOS)
+@available(macOS 10.15, *)
+extension TunnelsManager {
+    fileprivate func reinstateTunnel(reinstationData: CatalinaWorkaround.ReinstationData, completionHandler: @escaping (Bool) -> Void) {
+        let tunnelName = reinstationData.tunnelConfiguration.name ?? ""
+        if tunnelName.isEmpty {
+            completionHandler(false)
+            return
+        }
+
+        if tunnels.contains(where: { $0.name == tunnelName }) {
+            completionHandler(false)
+            return
+        }
+
+        let tunnelProviderProtocol = NETunnelProviderProtocol()
+        guard let appId = Bundle.main.bundleIdentifier else { fatalError() }
+        tunnelProviderProtocol.providerBundleIdentifier = "\(appId).network-extension"
+        tunnelProviderProtocol.passwordReference = reinstationData.keychainPasswordRef
+        tunnelProviderProtocol.providerConfiguration = ["UID": getuid()]
+        tunnelProviderProtocol.serverAddress = {
+            let endpoints = reinstationData.tunnelConfiguration.peers.compactMap { $0.endpoint }
+            if endpoints.count == 1 {
+                return endpoints[0].stringRepresentation
+            } else if endpoints.isEmpty {
+                return "Unspecified"
+            } else {
+                return "Multiple endpoints"
+            }
+        }()
+
+        let tunnelProvider = NETunnelProviderManager()
+        tunnelProvider.localizedDescription = tunnelName
+        tunnelProvider.protocolConfiguration = tunnelProviderProtocol
+        objc_setAssociatedObject(tunnelProvider, &NETunnelProviderManager.cachedConfigKey, reinstationData.tunnelConfiguration, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
+        tunnelProvider.isEnabled = true
+
+        tunnelProvider.saveToPreferences { [weak self] error in
+            guard error == nil else {
+                wg_log(.error, message: "Reinstate: Saving configuration failed: \(error!)")
+                completionHandler(false)
+                return
+            }
+
+            guard let self = self else { return }
+
+            let tunnel = TunnelContainer(tunnel: tunnelProvider)
+            self.tunnels.append(tunnel)
+            self.tunnels.sort { TunnelsManager.tunnelNameIsLessThan($0.name, $1.name) }
+            self.tunnelsListDelegate?.tunnelAdded(at: self.tunnels.firstIndex(of: tunnel)!)
+            completionHandler(true)
+        }
+    }
+}
+#endif