Allow users to import settings by pasting JSON blobs

Author: Jon Petersson

ios/MullvadREST/ApiHandlers/ServerRelaysResponse.swift

@@ -34,6 +34,19 @@ extension REST {
         public let ipv4AddrIn: IPv4Address
         public let weight: UInt64
         public let includeInCountry: Bool
+
+        public func copyWith(ipv4AddrIn: IPv4Address?) -> Self {
+            return BridgeRelay(
+                hostname: hostname,
+                active: active,
+                owned: owned,
+                location: location,
+                provider: provider,
+                ipv4AddrIn: ipv4AddrIn ?? self.ipv4AddrIn,
+                weight: weight,
+                includeInCountry: includeInCountry
+            )
+        }
     }
 
     public struct ServerRelay: Codable, Equatable {
@@ -47,6 +60,21 @@ extension REST {
         public let ipv6AddrIn: IPv6Address
         public let publicKey: Data
         public let includeInCountry: Bool
+
+        public func copyWith(ipv4AddrIn: IPv4Address?, ipv6AddrIn: IPv6Address?) -> Self {
+            return ServerRelay(
+                hostname: hostname,
+                active: active,
+                owned: owned,
+                location: location,
+                provider: provider,
+                weight: weight,
+                ipv4AddrIn: ipv4AddrIn ?? self.ipv4AddrIn,
+                ipv6AddrIn: ipv6AddrIn ?? self.ipv6AddrIn,
+                publicKey: publicKey,
+                includeInCountry: includeInCountry
+            )
+        }
     }
 
     public struct ServerWireguardTunnels: Codable, Equatable {

ios/MullvadREST/Relay/RelaySelector.swift

@@ -7,7 +7,9 @@
 //
 
 import Foundation
+import MullvadSettings
 import MullvadTypes
+import Network
 
 private let defaultPort: UInt16 = 53
 
@@ -19,15 +21,6 @@ public enum RelaySelector {
         relays.bridge.shadowsocks.filter { $0.protocol == "tcp" }.randomElement()
     }
 
-    /// Return a random Shadowsocks bridge relay, or `nil` if no relay were found.
-    ///
-    /// Non `active` relays are filtered out.
-    /// - Parameter relays: The list of relays to randomly select from.
-    /// - Returns: A Shadowsocks relay or `nil` if no active relay were found.
-    public static func shadowsocksRelay(from relaysResponse: REST.ServerRelaysResponse) -> REST.BridgeRelay? {
-        relaysResponse.bridge.relays.filter { $0.active }.randomElement()
-    }
-
     /// Returns the closest Shadowsocks relay using the given `constraints`, or a random relay if `constraints` were
     /// unsatisfiable.
     ///
@@ -41,7 +34,11 @@ public enum RelaySelector {
     ) -> REST.BridgeRelay? {
         let mappedBridges = mapRelays(relays: relaysResponse.bridge.relays, locations: relaysResponse.locations)
         let filteredRelays = applyConstraints(constraints, relays: mappedBridges)
-        guard filteredRelays.isEmpty == false else { return shadowsocksRelay(from: relaysResponse) }
+
+        guard filteredRelays.isEmpty == false else {
+            let relay = shadowsocksRelay(from: relaysResponse)
+            return relay.flatMap { applyIpOverrides(to: $0) }
+        }
 
         // Compute the midpoint location from all the filtered relays
         // Take *either* the first five relays, OR the relays below maximum bridge distance
@@ -77,7 +74,8 @@ public enum RelaySelector {
             UInt64(1 + greatestDistance - relay.distance)
         })
 
-        return randomRelay?.relay ?? filteredRelays.randomElement()?.relay
+        let relayToReturn = randomRelay?.relay ?? filteredRelays.randomElement()?.relay
+        return relayToReturn.flatMap { applyIpOverrides(to: $0) }
     }
 
     /**
@@ -97,10 +95,15 @@ public enum RelaySelector {
             numberOfFailedAttempts: numberOfFailedAttempts
         )
 
-        guard let relayWithLocation = pickRandomRelayByWeight(relays: filteredRelays), let port else {
+        guard var relayWithLocation = pickRandomRelayByWeight(relays: filteredRelays), let port else {
             throw NoRelaysSatisfyingConstraintsError()
         }
 
+        relayWithLocation = RelayWithLocation(
+            relay: applyIpOverrides(to: relayWithLocation.relay),
+            serverLocation: relayWithLocation.serverLocation
+        )
+
         let endpoint = MullvadEndpoint(
             ipv4Relay: IPv4Endpoint(
                 ip: relayWithLocation.relay.ipv4AddrIn,
@@ -135,6 +138,15 @@ public enum RelaySelector {
         }
     }
 
+    /// Return a random Shadowsocks bridge relay, or `nil` if no relay were found.
+    ///
+    /// Non `active` relays are filtered out.
+    /// - Parameter relays: The list of relays to randomly select from.
+    /// - Returns: A Shadowsocks relay or `nil` if no active relay were found.
+    private static func shadowsocksRelay(from relaysResponse: REST.ServerRelaysResponse) -> REST.BridgeRelay? {
+        relaysResponse.bridge.relays.filter { $0.active }.randomElement()
+    }
+
     /// Produce a list of `RelayWithLocation` items satisfying the given constraints
     private static func applyConstraints<T: AnyRelay>(
         _ constraints: RelayConstraints,
@@ -194,6 +206,21 @@ public enum RelaySelector {
         }
     }
 
+    private static func applyIpOverrides<T: AnyRelay>(to relay: T) -> T {
+        let overrides = IPOverrideRepository().fetchAll()
+
+        if let override = overrides.first(where: { host in
+            host.hostname == relay.hostname
+        }) {
+            return relay.copyWith(
+                ipv4AddrIn: override.ipv4Address,
+                ipv6AddrIn: override.ipv6Address
+            )
+        }
+
+        return relay
+    }
+
     private static func pickRandomRelayByWeight<T: AnyRelay>(relays: [RelayWithLocation<T>])
         -> RelayWithLocation<T>? {
         rouletteSelection(relays: relays, weightFunction: { relayWithLocation in relayWithLocation.relay.weight })
@@ -314,10 +341,16 @@ public protocol AnyRelay {
     var weight: UInt64 { get }
     var active: Bool { get }
     var includeInCountry: Bool { get }
+
+    func copyWith(ipv4AddrIn: IPv4Address?, ipv6AddrIn: IPv6Address?) -> Self
 }
 
 extension REST.ServerRelay: AnyRelay {}
-extension REST.BridgeRelay: AnyRelay {}
+extension REST.BridgeRelay: AnyRelay {
+    public func copyWith(ipv4AddrIn: IPv4Address?, ipv6AddrIn: IPv6Address?) -> REST.BridgeRelay {
+        copyWith(ipv4AddrIn: ipv4AddrIn)
+    }
+}
 
 private struct RelayWithLocation<T: AnyRelay> {
     let relay: T

ios/MullvadSettings/IPOverride.swift

@@ -0,0 +1,51 @@
+//
+//  IPOverride.swift
+//  MullvadVPN
+//
+//  Created by Jon Petersson on 2024-01-16.
+//  Copyright © 2024 Mullvad VPN AB. All rights reserved.
+//
+
+import Network
+
+public struct RelayOverrides: Codable {
+    public let overrides: [IPOverride]
+
+    private enum CodingKeys: String, CodingKey {
+        case overrides = "relay_overrides"
+    }
+}
+
+public struct IPOverride: Codable, Equatable {
+    public let hostname: String
+    public var ipv4Address: IPv4Address?
+    public var ipv6Address: IPv6Address?
+
+    private enum CodingKeys: String, CodingKey {
+        case hostname
+        case ipv4Address = "ipv4_addr_in"
+        case ipv6Address = "ipv6_addr_in"
+    }
+
+    init(hostname: String, ipv4Address: IPv4Address?, ipv6Address: IPv6Address?) throws {
+        self.hostname = hostname
+        self.ipv4Address = ipv4Address
+        self.ipv6Address = ipv6Address
+
+        if self.ipv4Address.isNil && self.ipv6Address.isNil {
+            throw NSError(domain: "IPOverrideInitDomain", code: NSFormattingError)
+        }
+    }
+
+    public init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        self.hostname = try container.decode(String.self, forKey: .hostname)
+        self.ipv4Address = try container.decodeIfPresent(IPv4Address.self, forKey: .ipv4Address)
+        self.ipv6Address = try container.decodeIfPresent(IPv6Address.self, forKey: .ipv6Address)
+
+        if self.ipv4Address.isNil && self.ipv6Address.isNil {
+            throw NSError(domain: "IPOverrideInitDomain", code: NSFormattingError)
+        }
+    }
+}

ios/MullvadSettings/IPOverrideRepository.swift

@@ -0,0 +1,90 @@
+//
+//  IPOverrideRepository.swift
+//  MullvadVPN
+//
+//  Created by Jon Petersson on 2024-01-16.
+//  Copyright © 2024 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+
+public protocol IPOverrideRepositoryProtocol {
+    func add(_ overrides: [IPOverride])
+    func fetchAll() -> [IPOverride]
+    func fetchByHostname(_ hostname: String) -> IPOverride?
+    func deleteAll()
+    func parseData(_ data: Data) throws -> [IPOverride]
+}
+
+public class IPOverrideRepository: IPOverrideRepositoryProtocol {
+    public init() {}
+
+    public func add(_ overrides: [IPOverride]) {
+        var storedOverrides = fetchAll()
+
+        overrides.forEach { override in
+            if let existingOverrideIndex = storedOverrides.firstIndex(where: { $0.hostname == override.hostname }) {
+                var existingOverride = storedOverrides[existingOverrideIndex]
+
+                if let ipv4Address = override.ipv4Address {
+                    existingOverride.ipv4Address = ipv4Address
+                }
+
+                if let ipv6Address = override.ipv6Address {
+                    existingOverride.ipv6Address = ipv6Address
+                }
+
+                storedOverrides[existingOverrideIndex] = existingOverride
+            } else {
+                storedOverrides.append(override)
+            }
+        }
+
+        do {
+            try writeIpOverrides(storedOverrides)
+        } catch {
+            print("Could not add override(s): \(overrides) \nError: \(error)")
+        }
+    }
+
+    public func fetchAll() -> [IPOverride] {
+        return (try? readIpOverrides()) ?? []
+    }
+
+    public func fetchByHostname(_ hostname: String) -> IPOverride? {
+        return fetchAll().first { $0.hostname == hostname }
+    }
+
+    public func deleteAll() {
+        do {
+            try SettingsManager.store.delete(key: .ipOverrides)
+        } catch {
+            print("Could not delete all overrides. \nError: \(error)")
+        }
+    }
+
+    public func parseData(_ data: Data) throws -> [IPOverride] {
+        let decoder = JSONDecoder()
+        let jsonData = try decoder.decode(RelayOverrides.self, from: data)
+
+        return jsonData.overrides
+    }
+
+    private func readIpOverrides() throws -> [IPOverride] {
+        let parser = makeParser()
+        let data = try SettingsManager.store.read(key: .ipOverrides)
+
+        return try parser.parseUnversionedPayload(as: [IPOverride].self, from: data)
+    }
+
+    private func writeIpOverrides(_ overrides: [IPOverride]) throws {
+        let parser = makeParser()
+        let data = try parser.produceUnversionedPayload(overrides)
+
+        try SettingsManager.store.write(data, for: .ipOverrides)
+    }
+
+    private func makeParser() -> SettingsParser {
+        SettingsParser(decoder: JSONDecoder(), encoder: JSONEncoder())
+    }
+}

ios/MullvadSettings/SettingsStore.swift

@@ -12,6 +12,7 @@ public enum SettingsKey: String, CaseIterable {
     case settings = "Settings"
     case deviceState = "DeviceState"
     case apiAccessMethods = "ApiAccessMethods"
+    case ipOverrides = "IPOverrides"
     case lastUsedAccount = "LastUsedAccount"
     case shouldWipeSettings = "ShouldWipeSettings"
 }