feat: native split-tunneling for xray (#1899)

* feat: integrated xray as a library and added split-tunneling

* fix: added copying amnezia_xray.dll to build dir

* fix: changed path on darwin

* chore: clean up getting default device

* chore: removed WSAGetLastError from sockopt logging

* fix: get rid of debug logs in xray handlers

* fix: minor fixes and xray debugging capabilities

* fix: macos default interface fix

* fix: roll-back ipv6 sockopt for mac

* fix: bind IPv6 on Windows

* fix: (win) better IPv6 handling and router fixes

* feat: prebuilts uploaded

* fix: removed redundant cmake definitions

* feat: moved xray to service process, reworked errors

* fix: return values in networkUtilities

* fix: macos build fixes

* fix: (windows) cmake fixes

* fix: (windows) compilation fix

* fix: (windows) changed location of amnezia_xray.dll

* feat: xray logs added to system service

* chore: bump xray&tun2socks versions for android

* chore: cleanup of XrayProtocol class
* removed killswitch
* removed redundant members and basic cleanup

* feat: support split-tunneling in iOS and macOS NE

* chore: update active interface index based on network path and available interfaces

* refactor: update network path handling and logging in PacketTunnelProvider

* chore: bump xray deps

---------

Co-authored-by: Yaroslav Yashin <yaroslav.yashin@gmail.com>

client/platforms/ios/PacketTunnelProvider+OpenVPN.swift

@@ -131,7 +131,7 @@ extension PacketTunnelProvider {
         }
 
         startHandler = completionHandler
-        ovpnAdapter?.connect(using: packetFlow)
+        ovpnAdapter?.connect(using: openVPNPacketFlow())
     }
 
     func handleOpenVPNStatusMessage(_ messageData: Data, completionHandler: ((Data?) -> Void)? = nil) {
@@ -153,7 +153,7 @@ extension PacketTunnelProvider {
     }
 
     func stopOpenVPN(with reason: NEProviderStopReason, completionHandler: @escaping () -> Void) {
-        ovpnLog(.info, message: "Stopping tunnel: reason: \(reason.description)")
+        ovpnLog(.info, message: "Stopping tunnel: reason: \(reason.amneziaDescription)")
 
         stopHandler = completionHandler
         if vpnReachability.isTracking {
@@ -293,5 +293,3 @@ extension PacketTunnelProvider: OpenVPNAdapterDelegate {
         ovpnLog(.info, message: logMessage)
     }
 }
-
-extension NEPacketTunnelFlow: OpenVPNAdapterPacketFlow {}

client/platforms/ios/PacketTunnelProvider+WireGuard.swift

@@ -176,7 +176,7 @@ extension PacketTunnelProvider {
     }
 
     func stopWireguard(with reason: NEProviderStopReason, completionHandler: @escaping () -> Void) {
-        wg_log(.info, message: "Stopping tunnel: reason: \(reason.description)")
+        wg_log(.info, message: "Stopping tunnel: reason: \(reason.amneziaDescription)")
 
         wgAdapter?.stop { error in
             ErrorNotifier.removeLastErrorFile()

client/platforms/ios/PacketTunnelProvider+Xray.swift

@@ -107,6 +107,8 @@ extension PacketTunnelProvider {
                     return
                 }
 
+                self?.updateActiveInterfaceIndexForCurrentPath()
+
                 // Launch xray
                 self?.setupAndStartXray(configData: updatedData) { xrayError in
                     if let xrayError {
@@ -133,6 +135,15 @@ extension PacketTunnelProvider {
         completionHandler()
     }
 
+    func sockCallback(fd: uintptr_t) {
+        if activeIfaceIdx != 0 {
+            withUnsafePointer(to: activeIfaceIdx) { ptr in
+                setsockopt(Int32(fd), IPPROTO_IP, IP_BOUND_IF, ptr, socklen_t(MemoryLayout<UInt32>.size))
+                setsockopt(Int32(fd), IPPROTO_IPV6, IPV6_BOUND_IF, ptr, socklen_t(MemoryLayout<UInt32>.size))
+            }
+        }
+    }
+
     private func setupAndStartXray(configData: Data,
                                    completionHandler: @escaping (Error?) -> Void) {
         let path = Constants.cachesDirectory.appendingPathComponent("config.json", isDirectory: false).path
@@ -142,6 +153,17 @@ extension PacketTunnelProvider {
             return
         }
 
+        updateActiveInterfaceIndexForCurrentPath()
+
+        let ctx = Unmanaged.passUnretained(self).toOpaque()
+        let cb: libxray_sockcallback = { (fd, ctx) in
+            guard let ctx = ctx else { return }
+            let instance = Unmanaged<PacketTunnelProvider>.fromOpaque(ctx).takeUnretainedValue()
+
+            instance.sockCallback(fd: fd)
+        }
+        LibXraySetSockCallback(cb, ctx)
+
         LibXrayRunXray(nil,
                        path,
                        Int64.max)

client/platforms/ios/PacketTunnelProvider.swift

@@ -1,5 +1,6 @@
 import Foundation
 import NetworkExtension
+import Network
 import os
 import Darwin
 import OpenVPNAdapter
@@ -38,6 +39,12 @@ struct Constants {
 class PacketTunnelProvider: NEPacketTunnelProvider {
     var wgAdapter: WireGuardAdapter?
     var ovpnAdapter: OpenVPNAdapter?
+    private lazy var openVPNPacketFlowAdapter = PacketTunnelFlowAdapter(flow: packetFlow)
+    private let pathMonitorQueue = DispatchQueue(label: Constants.processQueueName + ".path-monitor")
+    private let pathMonitor = NWPathMonitor()
+    private var didReceiveInitialPathUpdate = false
+    private var currentPath: Network.NWPath?
+    private var currentPathSignature: String?
 
     var splitTunnelType: Int?
     var splitTunnelSites: [String]?
@@ -47,6 +54,73 @@ class PacketTunnelProvider: NEPacketTunnelProvider {
     var startHandler: ((Error?) -> Void)?
     var stopHandler: (() -> Void)?
     var protoType: TunnelProtoType?
+    
+    var activeIfaceIdx: UInt32 = 0
+
+    func openVPNPacketFlow() -> OpenVPNAdapterPacketFlow {
+        openVPNPacketFlowAdapter
+    }
+
+    override init() {
+        super.init()
+        pathMonitor.pathUpdateHandler = { [weak self] path in
+            guard let self else { return }
+            self.currentPath = path
+            let signature = self.pathSignature(for: path)
+            let hasMeaningfulChange = self.currentPathSignature != signature
+            self.currentPathSignature = signature
+            self.updateActiveInterfaceIndex(for: path)
+
+            guard self.didReceiveInitialPathUpdate else {
+                self.didReceiveInitialPathUpdate = true
+                return
+            }
+
+            guard hasMeaningfulChange, self.protoType != nil else { return }
+
+            DispatchQueue.main.async {
+                self.handle(networkChange: path) { _ in }
+            }
+        }
+        pathMonitor.start(queue: pathMonitorQueue)
+
+        currentPath = pathMonitor.currentPath
+        currentPathSignature = pathSignature(for: pathMonitor.currentPath)
+    }
+
+    func updateActiveInterfaceIndex(for path: Network.NWPath?) {
+        guard let path else {
+            activeIfaceIdx = 0
+            return
+        }
+
+        let preferredTypes: [NWInterface.InterfaceType] = [.wiredEthernet, .wifi, .cellular, .other]
+
+        let nonLoopbackInterfaces = path.availableInterfaces.filter { $0.type != .loopback }
+        let activeInterfaces = nonLoopbackInterfaces.filter { path.usesInterfaceType($0.type) }
+
+        let candidate = preferredTypes.compactMap { type in
+            activeInterfaces.first { $0.type == type }
+        }.first ?? activeInterfaces.first ?? nonLoopbackInterfaces.first
+
+        if let candidate {
+            activeIfaceIdx = UInt32(candidate.index)
+        } else {
+            activeIfaceIdx = 0
+        }
+    }
+
+    func updateActiveInterfaceIndexForCurrentPath() {
+        if let currentPath {
+            currentPathSignature = pathSignature(for: currentPath)
+            updateActiveInterfaceIndex(for: currentPath)
+            return
+        }
+
+        currentPath = pathMonitor.currentPath
+        currentPathSignature = pathSignature(for: pathMonitor.currentPath)
+        updateActiveInterfaceIndex(for: pathMonitor.currentPath)
+    }
 
   override func handleAppMessage(_ messageData: Data, completionHandler: ((Data?) -> Void)? = nil) {
       guard let message = String(data: messageData, encoding: .utf8) else {
@@ -104,6 +178,9 @@ class PacketTunnelProvider: NEPacketTunnelProvider {
             return
         }
 
+        didReceiveInitialPathUpdate = false
+        updateActiveInterfaceIndexForCurrentPath()
+
         switch protoType {
         case .wireguard:
             startWireguard(activationAttemptId: activationAttemptId,
@@ -157,28 +234,63 @@ class PacketTunnelProvider: NEPacketTunnelProvider {
                                of object: Any?,
                                change: [NSKeyValueChangeKey: Any]?,
                                context: UnsafeMutableRawPointer?) {
-        guard Constants.kDefaultPathKey != keyPath else { return }
-        // Since iOS 11, we have observed that this KVO event fires repeatedly when connecting over Wifi,
-        // even though the underlying network has not changed (i.e. `isEqualToPath` returns false),
-        // leading to "wakeup crashes" due to excessive network activity. Guard against false positives by
-        // comparing the paths' string description, which includes properties not exposed by the class
-        guard let lastPath: NWPath = change?[.oldKey] as? NWPath,
-              let defPath = defaultPath,
-              lastPath != defPath || lastPath.description != defPath.description else {
+        guard Constants.kDefaultPathKey == keyPath else {
             return
         }
-        DispatchQueue.main.async { [weak self] in
-            guard let self, self.defaultPath != nil else { return }
-            self.handle(networkChange: self.defaultPath!) { _ in }
-        }
     }
   
-    private func handle(networkChange changePath: NWPath, completion: @escaping (Error?) -> Void) {
+    private func handle(networkChange changePath: Network.NWPath, completion: @escaping (Error?) -> Void) {
+        updateActiveInterfaceIndex(for: changePath)
         wg_log(.info, message: "Tunnel restarted.")
         startTunnel(options: nil, completionHandler: completion)
     }
 }
 
+private extension PacketTunnelProvider {
+    func pathSignature(for path: Network.NWPath) -> String {
+        var signatureComponents = [String(describing: path.status)]
+        signatureComponents.append(path.isExpensive ? "exp" : "noexp")
+        signatureComponents.append(path.isConstrained ? "con" : "nocon")
+
+        let preferredTypes: [NWInterface.InterfaceType] = [.wiredEthernet, .wifi, .cellular, .loopback, .other]
+        let sortedInterfaces = path.availableInterfaces.sorted { lhs, rhs in
+            if lhs.type == rhs.type {
+                return lhs.index < rhs.index
+            }
+
+            let lhsOrder = preferredTypes.firstIndex(of: lhs.type) ?? preferredTypes.count
+            let rhsOrder = preferredTypes.firstIndex(of: rhs.type) ?? preferredTypes.count
+
+            if lhsOrder == rhsOrder {
+                return lhs.index < rhs.index
+            }
+
+            return lhsOrder < rhsOrder
+        }
+
+        for interface in sortedInterfaces {
+            let typeName: String
+            switch interface.type {
+            case .wiredEthernet: typeName = "ethernet"
+            case .wifi: typeName = "wifi"
+            case .cellular: typeName = "cellular"
+            case .loopback: typeName = "loopback"
+            case .other: typeName = "other"
+            @unknown default: typeName = "unknown"
+            }
+            signatureComponents.append("\(typeName):\(interface.index)")
+        }
+
+        // Include currently used interface preference ordering
+        for type in preferredTypes {
+            let usesType = path.usesInterfaceType(type)
+            signatureComponents.append("uses-\(type):\(usesType)")
+        }
+
+        return signatureComponents.joined(separator: "|")
+    }
+}
+
 extension WireGuardLogLevel {
   var osLogLevel: OSLogType {
     switch self {
@@ -190,8 +302,27 @@ extension WireGuardLogLevel {
   }
 }
 
-extension NEProviderStopReason: CustomStringConvertible {
-  public var description: String {
+final class PacketTunnelFlowAdapter: NSObject, OpenVPNAdapterPacketFlow {
+  private let flow: NEPacketTunnelFlow
+
+  init(flow: NEPacketTunnelFlow) {
+    self.flow = flow
+    super.init()
+  }
+
+  @objc(readPacketsWithCompletionHandler:)
+  func readPackets(completionHandler: @escaping ([Data], [NSNumber]) -> Void) {
+    flow.readPackets(completionHandler: completionHandler)
+  }
+
+  @objc(writePackets:withProtocols:)
+  func writePackets(_ packets: [Data], withProtocols protocols: [NSNumber]) -> Bool {
+    flow.writePackets(packets, withProtocols: protocols)
+  }
+}
+
+extension NEProviderStopReason {
+  var amneziaDescription: String {
     switch self {
     case .none:
       return "No specific reason"
@@ -223,6 +354,8 @@ extension NEProviderStopReason: CustomStringConvertible {
       return "The current console user changed"
     case .connectionFailed:
       return "The connection failed"
+    case .internalError:
+      return "The network extension reported an internal error"
     case .sleep:
       return "A stop reason indicating the VPNC enabled disconnect on sleep and the device went to sleep"
     case .appUpdate: