Migrate settings to Version3 and introduce incremental migration scheme.

ios/MullvadREST/RESTAuthorization.swift

@@ -19,10 +19,10 @@ extension REST {
     typealias Authorization = String
 
     struct AccessTokenProvider: RESTAuthorizationProvider {
-        private let accessTokenManager: AccessTokenManager
+        private let accessTokenManager: RESTAccessTokenManagement
         private let accountNumber: String
 
-        init(accessTokenManager: AccessTokenManager, accountNumber: String) {
+        init(accessTokenManager: RESTAccessTokenManagement, accountNumber: String) {
             self.accessTokenManager = accessTokenManager
             self.accountNumber = accountNumber
         }

ios/MullvadREST/RESTProxy.swift

@@ -160,11 +160,11 @@ extension REST {
     }
 
     public class AuthProxyConfiguration: ProxyConfiguration {
-        public let accessTokenManager: AccessTokenManager
+        public let accessTokenManager: RESTAccessTokenManagement
 
         public init(
             proxyConfiguration: ProxyConfiguration,
-            accessTokenManager: AccessTokenManager
+            accessTokenManager: RESTAccessTokenManagement
         ) {
             self.accessTokenManager = accessTokenManager
 

ios/MullvadSettings/MigrationManager.swift

@@ -29,14 +29,18 @@ public struct MigrationManager {
 
     /// Migrate settings store if needed.
     ///
-    /// The following types of error are expected to be returned by this method:
-    /// `SettingsMigrationError`, `UnsupportedSettingsVersionError`, `ReadSettingsVersionError`.
+    /// Reads the current settings, upgrades them to the latest version if needed
+    /// and writes back to `store` when settings are updated.
+    /// - Parameters:
+    ///   - store: The store to from which settings are read and written to.
+    ///   - proxyFactory: Factory used for migrations that involve API calls.
+    ///   - migrationCompleted: Completion handler called with a migration result.
     public func migrateSettings(
         store: SettingsStore,
         proxyFactory: REST.ProxyFactory,
         migrationCompleted: @escaping (SettingsMigrationResult) -> Void
     ) {
-        let handleCompletion = { (result: SettingsMigrationResult) in
+        let resetStoreHandler = { (result: SettingsMigrationResult) in
             // Reset store upon failure to migrate settings.
             if case .failure = result {
                 SettingsManager.resetStore()
@@ -45,56 +49,59 @@ public struct MigrationManager {
         }
 
         do {
-            try checkLatestSettingsVersion(in: store)
-            handleCompletion(.nothing)
+            try upgradeSettingsToLatestVersion(
+                store: store,
+                proxyFactory: proxyFactory,
+                migrationCompleted: migrationCompleted
+            )
+        } catch .itemNotFound as KeychainError {
+            migrationCompleted(.nothing)
         } catch {
-            handleCompletion(.failure(error))
+            resetStoreHandler(.failure(error))
         }
     }
 
-    private func checkLatestSettingsVersion(in store: SettingsStore) throws {
-        let settingsVersion: Int
-        do {
-            let parser = SettingsParser(decoder: JSONDecoder(), encoder: JSONEncoder())
-            let settingsData = try store.read(key: SettingsKey.settings)
-            settingsVersion = try parser.parseVersion(data: settingsData)
-        } catch .itemNotFound as KeychainError {
+    private func upgradeSettingsToLatestVersion(
+        store: SettingsStore,
+        proxyFactory: REST.ProxyFactory,
+        migrationCompleted: @escaping (SettingsMigrationResult) -> Void
+    ) throws {
+        let parser = SettingsParser(decoder: JSONDecoder(), encoder: JSONEncoder())
+        let settingsData = try store.read(key: SettingsKey.settings)
+        let settingsVersion = try parser.parseVersion(data: settingsData)
+
+        // Special case downgrade attempts as nothing to do
+        guard settingsVersion < SchemaVersion.current.rawValue else {
+            migrationCompleted(.nothing)
             return
-        } catch {
-            throw ReadSettingsVersionError(underlyingError: error)
         }
 
-        guard settingsVersion != SchemaVersion.current.rawValue else {
+        // Corrupted settings version (i.e. negative values) should fail
+        guard let savedSchema = SchemaVersion(rawValue: settingsVersion) else {
+            migrationCompleted(.failure(UnsupportedSettingsVersionError(
+                storedVersion: settingsVersion,
+                currentVersion: SchemaVersion.current
+            )))
             return
         }
 
-        let error = UnsupportedSettingsVersionError(
-            storedVersion: settingsVersion,
-            currentVersion: SchemaVersion.current
-        )
-
-        logger.error(error: error, message: "Encountered an unknown version.")
-
-        throw error
-    }
-}
-
-/// A wrapper type for errors returned by concrete migrations.
-public struct SettingsMigrationError: LocalizedError, WrappingError {
-    private let inner: Error
-    public let sourceVersion, targetVersion: SchemaVersion
-
-    public var underlyingError: Error? {
-        inner
-    }
-
-    public var errorDescription: String? {
-        "Failed to migrate settings from \(sourceVersion) to \(targetVersion)."
-    }
-
-    public init(sourceVersion: SchemaVersion, targetVersion: SchemaVersion, underlyingError: Error) {
-        self.sourceVersion = sourceVersion
-        self.targetVersion = targetVersion
-        inner = underlyingError
+        var versionTypeCopy = savedSchema
+        let savedSettings = try parser.parsePayload(as: versionTypeCopy.settingsType, from: settingsData)
+        var latestSettings = savedSettings
+
+        repeat {
+            let upgradedVersion = latestSettings.upgradeToNextVersion(
+                store: store,
+                proxyFactory: proxyFactory,
+                parser: parser
+            )
+            versionTypeCopy = versionTypeCopy.nextVersion
+            latestSettings = upgradedVersion
+        } while versionTypeCopy.rawValue < SchemaVersion.current.rawValue
+
+        // Write the latest settings back to the store
+        let latestVersionPayload = try parser.producePayload(latestSettings, version: SchemaVersion.current.rawValue)
+        try store.write(latestVersionPayload, for: .settings)
+        migrationCompleted(.success)
     }
 }

ios/MullvadSettings/SettingsManager.swift

@@ -18,11 +18,28 @@ private let accountExpiryKey = "accountExpiry"
 public enum SettingsManager {
     private static let logger = Logger(label: "SettingsManager")
 
+    #if DEBUG
+    private static var _store = KeychainSettingsStore(
+        serviceName: keychainServiceName,
+        accessGroup: ApplicationConfiguration.securityGroupIdentifier
+    )
+
+    /// Alternative store used for tests.
+    internal static var unitTestStore: SettingsStore?
+
+    public static var store: SettingsStore {
+        if let unitTestStore { return unitTestStore }
+        return _store
+    }
+
+    #else
     public static let store: SettingsStore = KeychainSettingsStore(
         serviceName: keychainServiceName,
         accessGroup: ApplicationConfiguration.securityGroupIdentifier
     )
 
+    #endif
+
     private static func makeParser() -> SettingsParser {
         SettingsParser(decoder: JSONDecoder(), encoder: JSONEncoder())
     }

ios/MullvadSettings/StoredWgKeyData.swift

@@ -0,0 +1,37 @@
+//
+//  StoredWgKeyData.swift
+//  MullvadSettings
+//
+//  Created by Marco Nikic on 2023-10-23.
+//  Copyright © 2023 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+import WireGuardKitTypes
+
+public struct StoredWgKeyData: Codable, Equatable {
+    /// Private key creation date.
+    public var creationDate: Date
+
+    /// Last date a rotation was attempted. Nil if last attempt was successful.
+    public var lastRotationAttemptDate: Date?
+
+    /// Private key.
+    public var privateKey: PrivateKey
+
+    /// Next private key we're trying to rotate to.
+    /// Added in 2023.3
+    public var nextPrivateKey: PrivateKey?
+
+    public init(
+        creationDate: Date,
+        lastRotationAttemptDate: Date? = nil,
+        privateKey: PrivateKey,
+        nextPrivateKey: PrivateKey? = nil
+    ) {
+        self.creationDate = creationDate
+        self.lastRotationAttemptDate = lastRotationAttemptDate
+        self.privateKey = privateKey
+        self.nextPrivateKey = nextPrivateKey
+    }
+}

ios/MullvadSettings/TunnelSettings.swift

@@ -7,9 +7,19 @@
 //
 
 import Foundation
+import MullvadREST
 
 /// Alias to the latest version of the `TunnelSettings`.
-public typealias LatestTunnelSettings = TunnelSettingsV2
+public typealias LatestTunnelSettings = TunnelSettingsV3
+
+/// Protocol all TunnelSettings must adhere to, for upgrade purposes.
+public protocol TunnelSettings: Codable {
+    func upgradeToNextVersion(
+        store: SettingsStore,
+        proxyFactory: REST.ProxyFactory,
+        parser: SettingsParser
+    ) -> any TunnelSettings
+}
 
 /// Settings and device state schema versions.
 public enum SchemaVersion: Int, Equatable {
@@ -19,6 +29,33 @@ public enum SchemaVersion: Int, Equatable {
     /// New settings format, stored as `TunnelSettingsV2`.
     case v2 = 2
 
+    /// V2 format with wireGuard obfuscation options, stored as `TunnelSettingsV3`.
+    case v3 = 3
+
+    var settingsType: any TunnelSettings.Type {
+        switch self {
+        case .v1: return TunnelSettingsV1.self
+        case .v2: return TunnelSettingsV2.self
+        case .v3: return TunnelSettingsV3.self
+        }
+    }
+
+    var nextVersion: Self {
+        switch self {
+        case .v1: return .v2
+        case .v2: return .v3
+        case .v3: return .v3
+        }
+    }
+
+    var nextVersionType: any TunnelSettings.Type {
+        switch self {
+        case .v1: return TunnelSettingsV2.self
+        case .v2: return TunnelSettingsV3.self
+        case .v3: return TunnelSettingsV3.self
+        }
+    }
+
     /// Current schema version.
-    public static let current = SchemaVersion.v2
+    public static let current = SchemaVersion.v3
 }

ios/MullvadSettings/TunnelSettingsV1.swift

@@ -7,16 +7,25 @@
 //
 
 import Foundation
+import MullvadREST
 import MullvadTypes
 import struct Network.IPv4Address
 import struct WireGuardKitTypes.IPAddressRange
 import class WireGuardKitTypes.PrivateKey
 import class WireGuardKitTypes.PublicKey
 
 /// A struct that holds the configuration passed via `NETunnelProviderProtocol`.
-public struct TunnelSettingsV1: Codable, Equatable {
+public struct TunnelSettingsV1: Codable, Equatable, TunnelSettings {
     public var relayConstraints = RelayConstraints()
     public var interface = InterfaceSettings()
+
+    public func upgradeToNextVersion(
+        store: SettingsStore,
+        proxyFactory: REST.ProxyFactory,
+        parser: SettingsParser
+    ) -> any TunnelSettings {
+        TunnelSettingsV2(relayConstraints: relayConstraints, dnsSettings: interface.dnsSettings)
+    }
 }
 
 /// A struct that holds a tun interface configuration.

ios/MullvadSettings/TunnelSettingsV2.swift

@@ -7,13 +7,10 @@
 //
 
 import Foundation
+import MullvadREST
 import MullvadTypes
-import struct Network.IPv4Address
-import struct WireGuardKitTypes.IPAddressRange
-import class WireGuardKitTypes.PrivateKey
-import class WireGuardKitTypes.PublicKey
 
-public struct TunnelSettingsV2: Codable, Equatable {
+public struct TunnelSettingsV2: Codable, Equatable, TunnelSettings {
     /// Relay constraints.
     public var relayConstraints: RelayConstraints
 
@@ -27,31 +24,16 @@ public struct TunnelSettingsV2: Codable, Equatable {
         self.relayConstraints = relayConstraints
         self.dnsSettings = dnsSettings
     }
-}
-
-public struct StoredWgKeyData: Codable, Equatable {
-    /// Private key creation date.
-    public var creationDate: Date
-
-    /// Last date a rotation was attempted. Nil if last attempt was successful.
-    public var lastRotationAttemptDate: Date?
-
-    /// Private key.
-    public var privateKey: PrivateKey
 
-    /// Next private key we're trying to rotate to.
-    /// Added in 2023.3
-    public var nextPrivateKey: PrivateKey?
-
-    public init(
-        creationDate: Date,
-        lastRotationAttemptDate: Date? = nil,
-        privateKey: PrivateKey,
-        nextPrivateKey: PrivateKey? = nil
-    ) {
-        self.creationDate = creationDate
-        self.lastRotationAttemptDate = lastRotationAttemptDate
-        self.privateKey = privateKey
-        self.nextPrivateKey = nextPrivateKey
+    public func upgradeToNextVersion(
+        store: SettingsStore,
+        proxyFactory: REST.ProxyFactory,
+        parser: SettingsParser
+    ) -> any TunnelSettings {
+        TunnelSettingsV3(
+            relayConstraints: relayConstraints,
+            dnsSettings: dnsSettings,
+            wireGuardObfuscation: WireGuardObfuscationSettings()
+        )
     }
 }

ios/MullvadSettings/TunnelSettingsV3.swift

@@ -0,0 +1,40 @@
+//
+//  TunnelSettingsV3.swift
+//  MullvadVPN
+//
+//  Created by Marco Nikic on 2023-10-17.
+//  Copyright © 2023 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+import MullvadREST
+import MullvadTypes
+
+public struct TunnelSettingsV3: Codable, Equatable, TunnelSettings {
+    /// Relay constraints.
+    public var relayConstraints: RelayConstraints
+
+    /// DNS settings.
+    public var dnsSettings: DNSSettings
+
+    /// WireGuard obfuscation settings
+    public var wireGuardObfuscation: WireGuardObfuscationSettings
+
+    public init(
+        relayConstraints: RelayConstraints = RelayConstraints(),
+        dnsSettings: DNSSettings = DNSSettings(),
+        wireGuardObfuscation: WireGuardObfuscationSettings = WireGuardObfuscationSettings()
+    ) {
+        self.relayConstraints = relayConstraints
+        self.dnsSettings = dnsSettings
+        self.wireGuardObfuscation = wireGuardObfuscation
+    }
+
+    public func upgradeToNextVersion(
+        store: SettingsStore,
+        proxyFactory: REST.ProxyFactory,
+        parser: SettingsParser
+    ) -> any TunnelSettings {
+        self
+    }
+}