ios: PCA Phobos VPN for iPhone (source)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ios/WireGuardKit/COPYING

@@ -0,0 +1,19 @@
+Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

ios/WireGuardKit/Package.swift

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+// swift-tools-version:5.5
+// Vendored WireGuardKit (github.com/WireGuard/wireguard-apple, MIT). libwg-go.a is
+// prebuilt in ../WireGuardGo/<sdk>/ — the app target adds it to LIBRARY_SEARCH_PATHS.
+import PackageDescription
+
+let package = Package(
+    name: "WireGuardKit",
+    platforms: [.iOS(.v15)],
+    products: [.library(name: "WireGuardKit", targets: ["WireGuardKit"])],
+    targets: [
+        .target(name: "WireGuardKit", dependencies: ["WireGuardKitGo", "WireGuardKitC"]),
+        .target(name: "WireGuardKitC", publicHeadersPath: "."),
+        .target(name: "WireGuardKitGo", publicHeadersPath: ".", linkerSettings: [.linkedLibrary("wg-go")]),
+    ]
+)

ios/WireGuardKit/Sources/WireGuardKit/Array+ConcurrentMap.swift

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+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+extension Array {
+
+    /// Returns an array containing the results of mapping the given closure over the sequence’s
+    /// elements concurrently.
+    ///
+    /// - Parameters:
+    ///   - queue: The queue for performing concurrent computations.
+    ///            If the given queue is serial, the values are mapped in a serial fashion.
+    ///            Pass `nil` to perform computations on the current queue.
+    ///   - transform: the block to perform concurrent computations over the given element.
+    /// - Returns: an array of concurrently computed values.
+    func concurrentMap<U>(queue: DispatchQueue?, _ transform: (Element) -> U) -> [U] {
+        var result = [U?](repeating: nil, count: self.count)
+        let resultQueue = DispatchQueue(label: "ConcurrentMapQueue")
+
+        let execute = queue?.sync ?? { $0() }
+
+        execute {
+            DispatchQueue.concurrentPerform(iterations: self.count) { index in
+                let value = transform(self[index])
+                resultQueue.sync {
+                    result[index] = value
+                }
+            }
+        }
+
+        return result.map { $0! }
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/DNSResolver.swift

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+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Network
+import Foundation
+
+enum DNSResolver {}
+
+extension DNSResolver {
+
+    /// Concurrent queue used for DNS resolutions
+    private static let resolverQueue = DispatchQueue(label: "DNSResolverQueue", qos: .default, attributes: .concurrent)
+
+    static func resolveSync(endpoints: [Endpoint?]) -> [Result<Endpoint, DNSResolutionError>?] {
+        let isAllEndpointsAlreadyResolved = endpoints.allSatisfy { maybeEndpoint -> Bool in
+            return maybeEndpoint?.hasHostAsIPAddress() ?? true
+        }
+
+        if isAllEndpointsAlreadyResolved {
+            return endpoints.map { endpoint in
+                return endpoint.map { .success($0) }
+            }
+        }
+
+        return endpoints.concurrentMap(queue: resolverQueue) { endpoint -> Result<Endpoint, DNSResolutionError>? in
+            guard let endpoint = endpoint else { return nil }
+
+            if endpoint.hasHostAsIPAddress() {
+                return .success(endpoint)
+            } else {
+                return Result { try DNSResolver.resolveSync(endpoint: endpoint) }
+                    .mapError { error -> DNSResolutionError in
+                        // swiftlint:disable:next force_cast
+                        return error as! DNSResolutionError
+                    }
+            }
+        }
+    }
+
+    private static func resolveSync(endpoint: Endpoint) throws -> Endpoint {
+        guard case .name(let name, _) = endpoint.host else {
+            return endpoint
+        }
+
+        var hints = addrinfo()
+        hints.ai_flags = AI_ALL // We set this to ALL so that we get v4 addresses even on DNS64 networks
+        hints.ai_family = AF_UNSPEC
+        hints.ai_socktype = SOCK_DGRAM
+        hints.ai_protocol = IPPROTO_UDP
+
+        var resultPointer: UnsafeMutablePointer<addrinfo>?
+        defer {
+            resultPointer.flatMap { freeaddrinfo($0) }
+        }
+
+        let errorCode = getaddrinfo(name, "\(endpoint.port)", &hints, &resultPointer)
+        if errorCode != 0 {
+            throw DNSResolutionError(errorCode: errorCode, address: name)
+        }
+
+        var ipv4Address: IPv4Address?
+        var ipv6Address: IPv6Address?
+
+        var next: UnsafeMutablePointer<addrinfo>? = resultPointer
+        let iterator = AnyIterator { () -> addrinfo? in
+            let result = next?.pointee
+            next = result?.ai_next
+            return result
+        }
+
+        for addrInfo in iterator {
+            if let maybeIpv4Address = IPv4Address(addrInfo: addrInfo) {
+                ipv4Address = maybeIpv4Address
+                break // If we found an IPv4 address, we can stop
+            } else if let maybeIpv6Address = IPv6Address(addrInfo: addrInfo) {
+                ipv6Address = maybeIpv6Address
+                continue // If we already have an IPv6 address, we can skip this one
+            }
+        }
+
+        // We prefer an IPv4 address over an IPv6 address
+        if let ipv4Address = ipv4Address {
+            return Endpoint(host: .ipv4(ipv4Address), port: endpoint.port)
+        } else if let ipv6Address = ipv6Address {
+            return Endpoint(host: .ipv6(ipv6Address), port: endpoint.port)
+        } else {
+            // Must never happen
+            fatalError()
+        }
+    }
+}
+
+extension Endpoint {
+    func withReresolvedIP() throws -> Endpoint {
+        #if os(iOS)
+        let hostname: String
+        switch host {
+        case .name(let name, _):
+            hostname = name
+        case .ipv4(let address):
+            hostname = "\(address)"
+        case .ipv6(let address):
+            hostname = "\(address)"
+        @unknown default:
+            fatalError()
+        }
+
+        var hints = addrinfo()
+        hints.ai_family = AF_UNSPEC
+        hints.ai_socktype = SOCK_DGRAM
+        hints.ai_protocol = IPPROTO_UDP
+        hints.ai_flags = 0 // We set this to zero so that we actually resolve this using DNS64
+
+        var result: UnsafeMutablePointer<addrinfo>?
+        defer {
+            result.flatMap { freeaddrinfo($0) }
+        }
+
+        let errorCode = getaddrinfo(hostname, "\(self.port)", &hints, &result)
+        if errorCode != 0 {
+            throw DNSResolutionError(errorCode: errorCode, address: hostname)
+        }
+
+        let addrInfo = result!.pointee
+        if let ipv4Address = IPv4Address(addrInfo: addrInfo) {
+            return Endpoint(host: .ipv4(ipv4Address), port: port)
+        } else if let ipv6Address = IPv6Address(addrInfo: addrInfo) {
+            return Endpoint(host: .ipv6(ipv6Address), port: port)
+        } else {
+            fatalError()
+        }
+        #elseif os(macOS)
+        return self
+        #else
+        #error("Unimplemented")
+        #endif
+    }
+}
+
+/// An error type describing DNS resolution error
+public struct DNSResolutionError: LocalizedError {
+    public let errorCode: Int32
+    public let address: String
+
+    init(errorCode: Int32, address: String) {
+        self.errorCode = errorCode
+        self.address = address
+    }
+
+    public var errorDescription: String? {
+        return String(cString: gai_strerror(errorCode))
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/DNSServer.swift

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import Network
+
+public struct DNSServer {
+    public let address: IPAddress
+
+    public init(address: IPAddress) {
+        self.address = address
+    }
+}
+
+extension DNSServer: Equatable {
+    public static func == (lhs: DNSServer, rhs: DNSServer) -> Bool {
+        return lhs.address.rawValue == rhs.address.rawValue
+    }
+}
+
+extension DNSServer {
+    public var stringRepresentation: String {
+        return "\(address)"
+    }
+
+    public init?(from addressString: String) {
+        if let addr = IPv4Address(addressString) {
+            address = addr
+        } else if let addr = IPv6Address(addressString) {
+            address = addr
+        } else {
+            return nil
+        }
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/Endpoint.swift

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+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import Network
+
+public struct Endpoint {
+    public let host: NWEndpoint.Host
+    public let port: NWEndpoint.Port
+
+    public init(host: NWEndpoint.Host, port: NWEndpoint.Port) {
+        self.host = host
+        self.port = port
+    }
+}
+
+extension Endpoint: Equatable {
+    public static func == (lhs: Endpoint, rhs: Endpoint) -> Bool {
+        return lhs.host == rhs.host && lhs.port == rhs.port
+    }
+}
+
+extension Endpoint: Hashable {
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(host)
+        hasher.combine(port)
+    }
+}
+
+extension Endpoint {
+    public var stringRepresentation: String {
+        switch host {
+        case .name(let hostname, _):
+            return "\(hostname):\(port)"
+        case .ipv4(let address):
+            return "\(address):\(port)"
+        case .ipv6(let address):
+            return "[\(address)]:\(port)"
+        @unknown default:
+            fatalError()
+        }
+    }
+
+    public init?(from string: String) {
+        // Separation of host and port is based on 'parse_endpoint' function in
+        // https://git.zx2c4.com/wireguard-tools/tree/src/config.c
+        guard !string.isEmpty else { return nil }
+        let startOfPort: String.Index
+        let hostString: String
+        if string.first! == "[" {
+            // Look for IPv6-style endpoint, like [::1]:80
+            let startOfHost = string.index(after: string.startIndex)
+            guard let endOfHost = string.dropFirst().firstIndex(of: "]") else { return nil }
+            let afterEndOfHost = string.index(after: endOfHost)
+            if afterEndOfHost == string.endIndex { return nil }
+            guard string[afterEndOfHost] == ":" else { return nil }
+            startOfPort = string.index(after: afterEndOfHost)
+            hostString = String(string[startOfHost ..< endOfHost])
+        } else {
+            // Look for an IPv4-style endpoint, like 127.0.0.1:80
+            guard let endOfHost = string.firstIndex(of: ":") else { return nil }
+            startOfPort = string.index(after: endOfHost)
+            hostString = String(string[string.startIndex ..< endOfHost])
+        }
+        guard let endpointPort = NWEndpoint.Port(String(string[startOfPort ..< string.endIndex])) else { return nil }
+        let invalidCharacterIndex = hostString.unicodeScalars.firstIndex { char in
+            return !CharacterSet.urlHostAllowed.contains(char)
+        }
+        guard invalidCharacterIndex == nil else { return nil }
+        host = NWEndpoint.Host(hostString)
+        port = endpointPort
+    }
+}
+
+extension Endpoint {
+    public func hasHostAsIPAddress() -> Bool {
+        switch host {
+        case .name:
+            return false
+        case .ipv4:
+            return true
+        case .ipv6:
+            return true
+        @unknown default:
+            fatalError()
+        }
+    }
+
+    public func hostname() -> String? {
+        switch host {
+        case .name(let hostname, _):
+            return hostname
+        case .ipv4:
+            return nil
+        case .ipv6:
+            return nil
+        @unknown default:
+            fatalError()
+        }
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/IPAddress+AddrInfo.swift

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import Network
+
+extension IPv4Address {
+    init?(addrInfo: addrinfo) {
+        guard addrInfo.ai_family == AF_INET else { return nil }
+
+        let addressData = addrInfo.ai_addr.withMemoryRebound(to: sockaddr_in.self, capacity: 1) { ptr -> Data in
+            return Data(bytes: &ptr.pointee.sin_addr, count: MemoryLayout<in_addr>.size)
+        }
+
+        self.init(addressData)
+    }
+}
+
+extension IPv6Address {
+    init?(addrInfo: addrinfo) {
+        guard addrInfo.ai_family == AF_INET6 else { return nil }
+
+        let addressData = addrInfo.ai_addr.withMemoryRebound(to: sockaddr_in6.self, capacity: 1) { ptr -> Data in
+            return Data(bytes: &ptr.pointee.sin6_addr, count: MemoryLayout<in6_addr>.size)
+        }
+
+        self.init(addressData)
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/IPAddressRange.swift

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+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import Network
+
+public struct IPAddressRange {
+    public let address: IPAddress
+    public let networkPrefixLength: UInt8
+
+    init(address: IPAddress, networkPrefixLength: UInt8) {
+        self.address = address
+        self.networkPrefixLength = networkPrefixLength
+    }
+}
+
+extension IPAddressRange: Equatable {
+    public static func == (lhs: IPAddressRange, rhs: IPAddressRange) -> Bool {
+        return lhs.address.rawValue == rhs.address.rawValue && lhs.networkPrefixLength == rhs.networkPrefixLength
+    }
+}
+
+extension IPAddressRange: Hashable {
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(address.rawValue)
+        hasher.combine(networkPrefixLength)
+    }
+}
+
+extension IPAddressRange {
+    public var stringRepresentation: String {
+        return "\(address)/\(networkPrefixLength)"
+    }
+
+    public init?(from string: String) {
+        guard let parsed = IPAddressRange.parseAddressString(string) else { return nil }
+        address = parsed.0
+        networkPrefixLength = parsed.1
+    }
+
+    private static func parseAddressString(_ string: String) -> (IPAddress, UInt8)? {
+        let endOfIPAddress = string.lastIndex(of: "/") ?? string.endIndex
+        let addressString = String(string[string.startIndex ..< endOfIPAddress])
+        let address: IPAddress
+        if let addr = IPv4Address(addressString) {
+            address = addr
+        } else if let addr = IPv6Address(addressString) {
+            address = addr
+        } else {
+            return nil
+        }
+
+        let maxNetworkPrefixLength: UInt8 = address is IPv4Address ? 32 : 128
+        var networkPrefixLength: UInt8
+        if endOfIPAddress < string.endIndex { // "/" was located
+            let indexOfNetworkPrefixLength = string.index(after: endOfIPAddress)
+            guard indexOfNetworkPrefixLength < string.endIndex else { return nil }
+            let networkPrefixLengthSubstring = string[indexOfNetworkPrefixLength ..< string.endIndex]
+            guard let npl = UInt8(networkPrefixLengthSubstring) else { return nil }
+            networkPrefixLength = min(npl, maxNetworkPrefixLength)
+        } else {
+            networkPrefixLength = maxNetworkPrefixLength
+        }
+
+        return (address, networkPrefixLength)
+    }
+
+    public func subnetMask() -> IPAddress {
+        if address is IPv4Address {
+            let mask = networkPrefixLength > 0 ? ~UInt32(0) << (32 - networkPrefixLength) : UInt32(0)
+            let bytes = Data([
+                UInt8(truncatingIfNeeded: mask >> 24),
+                UInt8(truncatingIfNeeded: mask >> 16),
+                UInt8(truncatingIfNeeded: mask >> 8),
+                UInt8(truncatingIfNeeded: mask >> 0)
+            ])
+            return IPv4Address(bytes)!
+        }
+        if address is IPv6Address {
+            var bytes = Data(repeating: 0, count: 16)
+            for i in 0..<Int(networkPrefixLength/8) {
+                bytes[i] = 0xff
+            }
+            let nibble = networkPrefixLength % 32
+            if nibble != 0 {
+                let mask = ~UInt32(0) << (32 - nibble)
+                let i = Int(networkPrefixLength / 32 * 4)
+                bytes[i + 0] = UInt8(truncatingIfNeeded: mask >> 24)
+                bytes[i + 1] = UInt8(truncatingIfNeeded: mask >> 16)
+                bytes[i + 2] = UInt8(truncatingIfNeeded: mask >> 8)
+                bytes[i + 3] = UInt8(truncatingIfNeeded: mask >> 0)
+            }
+            return IPv6Address(bytes)!
+        }
+        fatalError()
+    }
+
+    public func maskedAddress() -> IPAddress {
+        let subnet = subnetMask().rawValue
+        var masked = Data(address.rawValue)
+        if subnet.count != masked.count {
+            fatalError()
+        }
+        for i in 0..<subnet.count {
+            masked[i] &= subnet[i]
+        }
+        if subnet.count == 4 {
+            return IPv4Address(masked)!
+        }
+        if subnet.count == 16 {
+            return IPv6Address(masked)!
+        }
+        fatalError()
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/InterfaceConfiguration.swift

@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import Network
+
+public struct InterfaceConfiguration {
+    public var privateKey: PrivateKey
+    public var addresses = [IPAddressRange]()
+    public var listenPort: UInt16?
+    public var mtu: UInt16?
+    public var dns = [DNSServer]()
+    public var dnsSearch = [String]()
+
+    public init(privateKey: PrivateKey) {
+        self.privateKey = privateKey
+    }
+}
+
+extension InterfaceConfiguration: Equatable {
+    public static func == (lhs: InterfaceConfiguration, rhs: InterfaceConfiguration) -> Bool {
+        let lhsAddresses = lhs.addresses.filter { $0.address is IPv4Address } + lhs.addresses.filter { $0.address is IPv6Address }
+        let rhsAddresses = rhs.addresses.filter { $0.address is IPv4Address } + rhs.addresses.filter { $0.address is IPv6Address }
+
+        return lhs.privateKey == rhs.privateKey &&
+            lhsAddresses == rhsAddresses &&
+            lhs.listenPort == rhs.listenPort &&
+            lhs.mtu == rhs.mtu &&
+            lhs.dns == rhs.dns &&
+            lhs.dnsSearch == rhs.dnsSearch
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/PacketTunnelSettingsGenerator.swift

@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import Network
+import NetworkExtension
+
+#if SWIFT_PACKAGE
+import WireGuardKitC
+#endif
+
+/// A type alias for `Result` type that holds a tuple with source and resolved endpoint.
+typealias EndpointResolutionResult = Result<(Endpoint, Endpoint), DNSResolutionError>
+
+class PacketTunnelSettingsGenerator {
+    let tunnelConfiguration: TunnelConfiguration
+    let resolvedEndpoints: [Endpoint?]
+
+    init(tunnelConfiguration: TunnelConfiguration, resolvedEndpoints: [Endpoint?]) {
+        self.tunnelConfiguration = tunnelConfiguration
+        self.resolvedEndpoints = resolvedEndpoints
+    }
+
+    func endpointUapiConfiguration() -> (String, [EndpointResolutionResult?]) {
+        var resolutionResults = [EndpointResolutionResult?]()
+        var wgSettings = ""
+
+        assert(tunnelConfiguration.peers.count == resolvedEndpoints.count)
+        for (peer, resolvedEndpoint) in zip(self.tunnelConfiguration.peers, self.resolvedEndpoints) {
+            wgSettings.append("public_key=\(peer.publicKey.hexKey)\n")
+
+            let result = resolvedEndpoint.map(Self.reresolveEndpoint)
+            if case .success((_, let resolvedEndpoint)) = result {
+                if case .name = resolvedEndpoint.host { assert(false, "Endpoint is not resolved") }
+                wgSettings.append("endpoint=\(resolvedEndpoint.stringRepresentation)\n")
+            }
+            resolutionResults.append(result)
+        }
+
+        return (wgSettings, resolutionResults)
+    }
+
+    func uapiConfiguration() -> (String, [EndpointResolutionResult?]) {
+        var resolutionResults = [EndpointResolutionResult?]()
+        var wgSettings = ""
+        wgSettings.append("private_key=\(tunnelConfiguration.interface.privateKey.hexKey)\n")
+        if let listenPort = tunnelConfiguration.interface.listenPort {
+            wgSettings.append("listen_port=\(listenPort)\n")
+        }
+        if !tunnelConfiguration.peers.isEmpty {
+            wgSettings.append("replace_peers=true\n")
+        }
+        assert(tunnelConfiguration.peers.count == resolvedEndpoints.count)
+        for (peer, resolvedEndpoint) in zip(self.tunnelConfiguration.peers, self.resolvedEndpoints) {
+            wgSettings.append("public_key=\(peer.publicKey.hexKey)\n")
+            if let preSharedKey = peer.preSharedKey?.hexKey {
+                wgSettings.append("preshared_key=\(preSharedKey)\n")
+            }
+
+            let result = resolvedEndpoint.map(Self.reresolveEndpoint)
+            if case .success((_, let resolvedEndpoint)) = result {
+                if case .name = resolvedEndpoint.host { assert(false, "Endpoint is not resolved") }
+                wgSettings.append("endpoint=\(resolvedEndpoint.stringRepresentation)\n")
+            }
+            resolutionResults.append(result)
+
+            let persistentKeepAlive = peer.persistentKeepAlive ?? 0
+            wgSettings.append("persistent_keepalive_interval=\(persistentKeepAlive)\n")
+            if !peer.allowedIPs.isEmpty {
+                wgSettings.append("replace_allowed_ips=true\n")
+                peer.allowedIPs.forEach { wgSettings.append("allowed_ip=\($0.stringRepresentation)\n") }
+            }
+        }
+        return (wgSettings, resolutionResults)
+    }
+
+    func generateNetworkSettings() -> NEPacketTunnelNetworkSettings {
+        /* iOS requires a tunnel endpoint, whereas in WireGuard it's valid for
+         * a tunnel to have no endpoint, or for there to be many endpoints, in
+         * which case, displaying a single one in settings doesn't really
+         * make sense. So, we fill it in with this placeholder, which is not
+         * a valid IP address that will actually route over the Internet.
+         */
+        let networkSettings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: "127.0.0.1")
+
+        if !tunnelConfiguration.interface.dnsSearch.isEmpty || !tunnelConfiguration.interface.dns.isEmpty {
+            let dnsServerStrings = tunnelConfiguration.interface.dns.map { $0.stringRepresentation }
+            let dnsSettings = NEDNSSettings(servers: dnsServerStrings)
+            dnsSettings.searchDomains = tunnelConfiguration.interface.dnsSearch
+            if !tunnelConfiguration.interface.dns.isEmpty {
+                dnsSettings.matchDomains = [""] // All DNS queries must first go through the tunnel's DNS
+            }
+            networkSettings.dnsSettings = dnsSettings
+        }
+
+        let mtu = tunnelConfiguration.interface.mtu ?? 0
+
+        /* 0 means automatic MTU. In theory, we should just do
+         * `networkSettings.tunnelOverheadBytes = 80` but in
+         * practice there are too many broken networks out there.
+         * Instead set it to 1280. Boohoo. Maybe someday we'll
+         * add a nob, maybe, or iOS will do probing for us.
+         */
+        if mtu == 0 {
+            #if os(iOS)
+            networkSettings.mtu = NSNumber(value: 1280)
+            #elseif os(macOS)
+            networkSettings.tunnelOverheadBytes = 80
+            #else
+            #error("Unimplemented")
+            #endif
+        } else {
+            networkSettings.mtu = NSNumber(value: mtu)
+        }
+
+        let (ipv4Addresses, ipv6Addresses) = addresses()
+        let (ipv4IncludedRoutes, ipv6IncludedRoutes) = includedRoutes()
+
+        let ipv4Settings = NEIPv4Settings(addresses: ipv4Addresses.map { $0.destinationAddress }, subnetMasks: ipv4Addresses.map { $0.destinationSubnetMask })
+        ipv4Settings.includedRoutes = ipv4IncludedRoutes
+        networkSettings.ipv4Settings = ipv4Settings
+
+        let ipv6Settings = NEIPv6Settings(addresses: ipv6Addresses.map { $0.destinationAddress }, networkPrefixLengths: ipv6Addresses.map { $0.destinationNetworkPrefixLength })
+        ipv6Settings.includedRoutes = ipv6IncludedRoutes
+        networkSettings.ipv6Settings = ipv6Settings
+
+        return networkSettings
+    }
+
+    private func addresses() -> ([NEIPv4Route], [NEIPv6Route]) {
+        var ipv4Routes = [NEIPv4Route]()
+        var ipv6Routes = [NEIPv6Route]()
+        for addressRange in tunnelConfiguration.interface.addresses {
+            if addressRange.address is IPv4Address {
+                ipv4Routes.append(NEIPv4Route(destinationAddress: "\(addressRange.address)", subnetMask: "\(addressRange.subnetMask())"))
+            } else if addressRange.address is IPv6Address {
+                /* Big fat ugly hack for broken iOS networking stack: the smallest prefix that will have
+                 * any effect on iOS is a /120, so we clamp everything above to /120. This is potentially
+                 * very bad, if various network parameters were actually relying on that subnet being
+                 * intentionally small. TODO: talk about this with upstream iOS devs.
+                 */
+                ipv6Routes.append(NEIPv6Route(destinationAddress: "\(addressRange.address)", networkPrefixLength: NSNumber(value: min(120, addressRange.networkPrefixLength))))
+            }
+        }
+        return (ipv4Routes, ipv6Routes)
+    }
+
+    private func includedRoutes() -> ([NEIPv4Route], [NEIPv6Route]) {
+        var ipv4IncludedRoutes = [NEIPv4Route]()
+        var ipv6IncludedRoutes = [NEIPv6Route]()
+
+        for addressRange in tunnelConfiguration.interface.addresses {
+            if addressRange.address is IPv4Address {
+                let route = NEIPv4Route(destinationAddress: "\(addressRange.maskedAddress())", subnetMask: "\(addressRange.subnetMask())")
+                route.gatewayAddress = "\(addressRange.address)"
+                ipv4IncludedRoutes.append(route)
+            } else if addressRange.address is IPv6Address {
+                let route = NEIPv6Route(destinationAddress: "\(addressRange.maskedAddress())", networkPrefixLength: NSNumber(value: addressRange.networkPrefixLength))
+                route.gatewayAddress = "\(addressRange.address)"
+                ipv6IncludedRoutes.append(route)
+            }
+        }
+
+        for peer in tunnelConfiguration.peers {
+            for addressRange in peer.allowedIPs {
+                if addressRange.address is IPv4Address {
+                    ipv4IncludedRoutes.append(NEIPv4Route(destinationAddress: "\(addressRange.address)", subnetMask: "\(addressRange.subnetMask())"))
+                } else if addressRange.address is IPv6Address {
+                    ipv6IncludedRoutes.append(NEIPv6Route(destinationAddress: "\(addressRange.address)", networkPrefixLength: NSNumber(value: addressRange.networkPrefixLength)))
+                }
+            }
+        }
+        return (ipv4IncludedRoutes, ipv6IncludedRoutes)
+    }
+
+    private class func reresolveEndpoint(endpoint: Endpoint) -> EndpointResolutionResult {
+        return Result { (endpoint, try endpoint.withReresolvedIP()) }
+            .mapError { error -> DNSResolutionError in
+                // swiftlint:disable:next force_cast
+                return error as! DNSResolutionError
+            }
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/PeerConfiguration.swift

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+public struct PeerConfiguration {
+    public var publicKey: PublicKey
+    public var preSharedKey: PreSharedKey?
+    public var allowedIPs = [IPAddressRange]()
+    public var endpoint: Endpoint?
+    public var persistentKeepAlive: UInt16?
+    public var rxBytes: UInt64?
+    public var txBytes: UInt64?
+    public var lastHandshakeTime: Date?
+
+    public init(publicKey: PublicKey) {
+        self.publicKey = publicKey
+    }
+}
+
+extension PeerConfiguration: Equatable {
+    public static func == (lhs: PeerConfiguration, rhs: PeerConfiguration) -> Bool {
+        return lhs.publicKey == rhs.publicKey &&
+            lhs.preSharedKey == rhs.preSharedKey &&
+            Set(lhs.allowedIPs) == Set(rhs.allowedIPs) &&
+            lhs.endpoint == rhs.endpoint &&
+            lhs.persistentKeepAlive == rhs.persistentKeepAlive
+    }
+}
+
+extension PeerConfiguration: Hashable {
+    public func hash(into hasher: inout Hasher) {
+        hasher.combine(publicKey)
+        hasher.combine(preSharedKey)
+        hasher.combine(Set(allowedIPs))
+        hasher.combine(endpoint)
+        hasher.combine(persistentKeepAlive)
+
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/PrivateKey.swift

@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+#if SWIFT_PACKAGE
+import WireGuardKitC
+#endif
+
+/// The class describing a private key used by WireGuard.
+public class PrivateKey: BaseKey {
+    /// Derived public key
+    public var publicKey: PublicKey {
+        return rawValue.withUnsafeBytes { (privateKeyBufferPointer: UnsafeRawBufferPointer) -> PublicKey in
+            var publicKeyData = Data(repeating: 0, count: Int(WG_KEY_LEN))
+            let privateKeyBytes = privateKeyBufferPointer.baseAddress!.assumingMemoryBound(to: UInt8.self)
+
+            publicKeyData.withUnsafeMutableBytes { (publicKeyBufferPointer: UnsafeMutableRawBufferPointer) in
+                let publicKeyBytes = publicKeyBufferPointer.baseAddress!.assumingMemoryBound(to: UInt8.self)
+                curve25519_derive_public_key(publicKeyBytes, privateKeyBytes)
+            }
+
+            return PublicKey(rawValue: publicKeyData)!
+        }
+    }
+
+    /// Initialize new private key
+    convenience public init() {
+        var privateKeyData = Data(repeating: 0, count: Int(WG_KEY_LEN))
+        privateKeyData.withUnsafeMutableBytes { (rawBufferPointer: UnsafeMutableRawBufferPointer) in
+            let privateKeyBytes = rawBufferPointer.baseAddress!.assumingMemoryBound(to: UInt8.self)
+            curve25519_generate_private_key(privateKeyBytes)
+        }
+        self.init(rawValue: privateKeyData)!
+    }
+}
+
+/// The class describing a public key used by WireGuard.
+public class PublicKey: BaseKey {}
+
+/// The class describing a pre-shared key used by WireGuard.
+public class PreSharedKey: BaseKey {}
+
+/// The base key implementation. Should not be used directly.
+public class BaseKey: RawRepresentable, Equatable, Hashable {
+    /// Raw key representation
+    public let rawValue: Data
+
+    /// Hex encoded representation
+    public var hexKey: String {
+        return rawValue.withUnsafeBytes { (rawBufferPointer: UnsafeRawBufferPointer) -> String in
+            let inBytes = rawBufferPointer.baseAddress!.assumingMemoryBound(to: UInt8.self)
+            var outBytes = [CChar](repeating: 0, count: Int(WG_KEY_LEN_HEX))
+            key_to_hex(&outBytes, inBytes)
+            return String(cString: outBytes, encoding: .ascii)!
+        }
+    }
+
+    /// Base64 encoded representation
+    public var base64Key: String {
+        return rawValue.withUnsafeBytes { (rawBufferPointer: UnsafeRawBufferPointer) -> String in
+            let inBytes = rawBufferPointer.baseAddress!.assumingMemoryBound(to: UInt8.self)
+            var outBytes = [CChar](repeating: 0, count: Int(WG_KEY_LEN_BASE64))
+            key_to_base64(&outBytes, inBytes)
+            return String(cString: outBytes, encoding: .ascii)!
+        }
+    }
+
+    /// Initialize the key with existing raw representation
+    required public init?(rawValue: Data) {
+        if rawValue.count == WG_KEY_LEN {
+            self.rawValue = rawValue
+        } else {
+            return nil
+        }
+    }
+
+    /// Initialize the key with hex representation
+    public convenience init?(hexKey: String) {
+        var bytes = Data(repeating: 0, count: Int(WG_KEY_LEN))
+        let success = bytes.withUnsafeMutableBytes { (bufferPointer: UnsafeMutableRawBufferPointer) -> Bool in
+            return key_from_hex(bufferPointer.baseAddress!.assumingMemoryBound(to: UInt8.self), hexKey)
+        }
+        if success {
+            self.init(rawValue: bytes)
+        } else {
+            return nil
+        }
+    }
+
+    /// Initialize the key with base64 representation
+    public convenience init?(base64Key: String) {
+        var bytes = Data(repeating: 0, count: Int(WG_KEY_LEN))
+        let success = bytes.withUnsafeMutableBytes { (bufferPointer: UnsafeMutableRawBufferPointer) -> Bool in
+            return key_from_base64(bufferPointer.baseAddress!.assumingMemoryBound(to: UInt8.self), base64Key)
+        }
+        if success {
+            self.init(rawValue: bytes)
+        } else {
+            return nil
+        }
+    }
+
+    public static func == (lhs: BaseKey, rhs: BaseKey) -> Bool {
+        return lhs.rawValue.withUnsafeBytes { (lhsBytes: UnsafeRawBufferPointer) -> Bool in
+            return rhs.rawValue.withUnsafeBytes { (rhsBytes: UnsafeRawBufferPointer) -> Bool in
+                return key_eq(
+                    lhsBytes.baseAddress!.assumingMemoryBound(to: UInt8.self),
+                    rhsBytes.baseAddress!.assumingMemoryBound(to: UInt8.self)
+                )
+            }
+        }
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/TunnelConfiguration.swift

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+public final class TunnelConfiguration {
+    public var name: String?
+    public var interface: InterfaceConfiguration
+    public let peers: [PeerConfiguration]
+
+    public init(name: String?, interface: InterfaceConfiguration, peers: [PeerConfiguration]) {
+        self.interface = interface
+        self.peers = peers
+        self.name = name
+
+        let peerPublicKeysArray = peers.map { $0.publicKey }
+        let peerPublicKeysSet = Set<PublicKey>(peerPublicKeysArray)
+        if peerPublicKeysArray.count != peerPublicKeysSet.count {
+            fatalError("Two or more peers cannot have the same public key")
+        }
+    }
+}
+
+extension TunnelConfiguration: Equatable {
+    public static func == (lhs: TunnelConfiguration, rhs: TunnelConfiguration) -> Bool {
+        return lhs.name == rhs.name &&
+            lhs.interface == rhs.interface &&
+            Set(lhs.peers) == Set(rhs.peers)
+    }
+}

ios/WireGuardKit/Sources/WireGuardKit/WireGuardAdapter.swift

@@ -0,0 +1,487 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+import NetworkExtension
+
+#if SWIFT_PACKAGE
+import WireGuardKitGo
+import WireGuardKitC
+#endif
+
+public enum WireGuardAdapterError: Error {
+    /// Failure to locate tunnel file descriptor.
+    case cannotLocateTunnelFileDescriptor
+
+    /// Failure to perform an operation in such state.
+    case invalidState
+
+    /// Failure to resolve endpoints.
+    case dnsResolution([DNSResolutionError])
+
+    /// Failure to set network settings.
+    case setNetworkSettings(Error)
+
+    /// Failure to start WireGuard backend.
+    case startWireGuardBackend(Int32)
+}
+
+/// Enum representing internal state of the `WireGuardAdapter`
+private enum State {
+    /// The tunnel is stopped
+    case stopped
+
+    /// The tunnel is up and running
+    case started(_ handle: Int32, _ settingsGenerator: PacketTunnelSettingsGenerator)
+
+    /// The tunnel is temporarily shutdown due to device going offline
+    case temporaryShutdown(_ settingsGenerator: PacketTunnelSettingsGenerator)
+}
+
+public class WireGuardAdapter {
+    public typealias LogHandler = (WireGuardLogLevel, String) -> Void
+
+    /// Network routes monitor.
+    private var networkMonitor: NWPathMonitor?
+
+    /// Packet tunnel provider.
+    private weak var packetTunnelProvider: NEPacketTunnelProvider?
+
+    /// Log handler closure.
+    private let logHandler: LogHandler
+
+    /// Private queue used to synchronize access to `WireGuardAdapter` members.
+    private let workQueue = DispatchQueue(label: "WireGuardAdapterWorkQueue")
+
+    /// Adapter state.
+    private var state: State = .stopped
+
+    /// Tunnel device file descriptor.
+    private var tunnelFileDescriptor: Int32? {
+        var ctlInfo = ctl_info()
+        withUnsafeMutablePointer(to: &ctlInfo.ctl_name) {
+            $0.withMemoryRebound(to: CChar.self, capacity: MemoryLayout.size(ofValue: $0.pointee)) {
+                _ = strcpy($0, "com.apple.net.utun_control")
+            }
+        }
+        for fd: Int32 in 0...1024 {
+            var addr = sockaddr_ctl()
+            var ret: Int32 = -1
+            var len = socklen_t(MemoryLayout.size(ofValue: addr))
+            withUnsafeMutablePointer(to: &addr) {
+                $0.withMemoryRebound(to: sockaddr.self, capacity: 1) {
+                    ret = getpeername(fd, $0, &len)
+                }
+            }
+            if ret != 0 || addr.sc_family != AF_SYSTEM {
+                continue
+            }
+            if ctlInfo.ctl_id == 0 {
+                ret = ioctl(fd, CTLIOCGINFO, &ctlInfo)
+                if ret != 0 {
+                    continue
+                }
+            }
+            if addr.sc_id == ctlInfo.ctl_id {
+                return fd
+            }
+        }
+        return nil
+    }
+
+    /// Returns a WireGuard version.
+    class var backendVersion: String {
+        guard let ver = wgVersion() else { return "unknown" }
+        let str = String(cString: ver)
+        free(UnsafeMutableRawPointer(mutating: ver))
+        return str
+    }
+
+    /// Returns the tunnel device interface name, or nil on error.
+    /// - Returns: String.
+    public var interfaceName: String? {
+        guard let tunnelFileDescriptor = self.tunnelFileDescriptor else { return nil }
+
+        var buffer = [UInt8](repeating: 0, count: Int(IFNAMSIZ))
+
+        return buffer.withUnsafeMutableBufferPointer { mutableBufferPointer in
+            guard let baseAddress = mutableBufferPointer.baseAddress else { return nil }
+
+            var ifnameSize = socklen_t(IFNAMSIZ)
+            let result = getsockopt(
+                tunnelFileDescriptor,
+                2 /* SYSPROTO_CONTROL */,
+                2 /* UTUN_OPT_IFNAME */,
+                baseAddress,
+                &ifnameSize)
+
+            if result == 0 {
+                return String(cString: baseAddress)
+            } else {
+                return nil
+            }
+        }
+    }
+
+    // MARK: - Initialization
+
+    /// Designated initializer.
+    /// - Parameter packetTunnelProvider: an instance of `NEPacketTunnelProvider`. Internally stored
+    ///   as a weak reference.
+    /// - Parameter logHandler: a log handler closure.
+    public init(with packetTunnelProvider: NEPacketTunnelProvider, logHandler: @escaping LogHandler) {
+        self.packetTunnelProvider = packetTunnelProvider
+        self.logHandler = logHandler
+
+        setupLogHandler()
+    }
+
+    deinit {
+        // Force remove logger to make sure that no further calls to the instance of this class
+        // can happen after deallocation.
+        wgSetLogger(nil, nil)
+
+        // Cancel network monitor
+        networkMonitor?.cancel()
+
+        // Shutdown the tunnel
+        if case .started(let handle, _) = self.state {
+            wgTurnOff(handle)
+        }
+    }
+
+    // MARK: - Public methods
+
+    /// Returns a runtime configuration from WireGuard.
+    /// - Parameter completionHandler: completion handler.
+    public func getRuntimeConfiguration(completionHandler: @escaping (String?) -> Void) {
+        workQueue.async {
+            guard case .started(let handle, _) = self.state else {
+                completionHandler(nil)
+                return
+            }
+
+            if let settings = wgGetConfig(handle) {
+                completionHandler(String(cString: settings))
+                free(settings)
+            } else {
+                completionHandler(nil)
+            }
+        }
+    }
+
+    /// Start the tunnel tunnel.
+    /// - Parameters:
+    ///   - tunnelConfiguration: tunnel configuration.
+    ///   - completionHandler: completion handler.
+    public func start(tunnelConfiguration: TunnelConfiguration, completionHandler: @escaping (WireGuardAdapterError?) -> Void) {
+        workQueue.async {
+            guard case .stopped = self.state else {
+                completionHandler(.invalidState)
+                return
+            }
+
+            let networkMonitor = NWPathMonitor()
+            networkMonitor.pathUpdateHandler = { [weak self] path in
+                self?.didReceivePathUpdate(path: path)
+            }
+            networkMonitor.start(queue: self.workQueue)
+
+            do {
+                let settingsGenerator = try self.makeSettingsGenerator(with: tunnelConfiguration)
+                try self.setNetworkSettings(settingsGenerator.generateNetworkSettings())
+
+                let (wgConfig, resolutionResults) = settingsGenerator.uapiConfiguration()
+                self.logEndpointResolutionResults(resolutionResults)
+
+                self.state = .started(
+                    try self.startWireGuardBackend(wgConfig: wgConfig),
+                    settingsGenerator
+                )
+                self.networkMonitor = networkMonitor
+                completionHandler(nil)
+            } catch let error as WireGuardAdapterError {
+                networkMonitor.cancel()
+                completionHandler(error)
+            } catch {
+                fatalError()
+            }
+        }
+    }
+
+    /// Stop the tunnel.
+    /// - Parameter completionHandler: completion handler.
+    public func stop(completionHandler: @escaping (WireGuardAdapterError?) -> Void) {
+        workQueue.async {
+            switch self.state {
+            case .started(let handle, _):
+                wgTurnOff(handle)
+
+            case .temporaryShutdown:
+                break
+
+            case .stopped:
+                completionHandler(.invalidState)
+                return
+            }
+
+            self.networkMonitor?.cancel()
+            self.networkMonitor = nil
+
+            self.state = .stopped
+
+            completionHandler(nil)
+        }
+    }
+
+    /// Update runtime configuration.
+    /// - Parameters:
+    ///   - tunnelConfiguration: tunnel configuration.
+    ///   - completionHandler: completion handler.
+    public func update(tunnelConfiguration: TunnelConfiguration, completionHandler: @escaping (WireGuardAdapterError?) -> Void) {
+        workQueue.async {
+            if case .stopped = self.state {
+                completionHandler(.invalidState)
+                return
+            }
+
+            // Tell the system that the tunnel is going to reconnect using new WireGuard
+            // configuration.
+            // This will broadcast the `NEVPNStatusDidChange` notification to the GUI process.
+            self.packetTunnelProvider?.reasserting = true
+            defer {
+                self.packetTunnelProvider?.reasserting = false
+            }
+
+            do {
+                let settingsGenerator = try self.makeSettingsGenerator(with: tunnelConfiguration)
+                try self.setNetworkSettings(settingsGenerator.generateNetworkSettings())
+
+                switch self.state {
+                case .started(let handle, _):
+                    let (wgConfig, resolutionResults) = settingsGenerator.uapiConfiguration()
+                    self.logEndpointResolutionResults(resolutionResults)
+
+                    wgSetConfig(handle, wgConfig)
+                    #if os(iOS)
+                    wgDisableSomeRoamingForBrokenMobileSemantics(handle)
+                    #endif
+
+                    self.state = .started(handle, settingsGenerator)
+
+                case .temporaryShutdown:
+                    self.state = .temporaryShutdown(settingsGenerator)
+
+                case .stopped:
+                    fatalError()
+                }
+
+                completionHandler(nil)
+            } catch let error as WireGuardAdapterError {
+                completionHandler(error)
+            } catch {
+                fatalError()
+            }
+        }
+    }
+
+    // MARK: - Private methods
+
+    /// Setup WireGuard log handler.
+    private func setupLogHandler() {
+        let context = Unmanaged.passUnretained(self).toOpaque()
+        wgSetLogger(context) { context, logLevel, message in
+            guard let context = context, let message = message else { return }
+
+            let unretainedSelf = Unmanaged<WireGuardAdapter>.fromOpaque(context)
+                .takeUnretainedValue()
+
+            let swiftString = String(cString: message).trimmingCharacters(in: .newlines)
+            let tunnelLogLevel = WireGuardLogLevel(rawValue: logLevel) ?? .verbose
+
+            unretainedSelf.logHandler(tunnelLogLevel, swiftString)
+        }
+    }
+
+    /// Set network tunnel configuration.
+    /// This method ensures that the call to `setTunnelNetworkSettings` does not time out, as in
+    /// certain scenarios the completion handler given to it may not be invoked by the system.
+    ///
+    /// - Parameters:
+    ///   - networkSettings: an instance of type `NEPacketTunnelNetworkSettings`.
+    /// - Throws: an error of type `WireGuardAdapterError`.
+    /// - Returns: `PacketTunnelSettingsGenerator`.
+    private func setNetworkSettings(_ networkSettings: NEPacketTunnelNetworkSettings) throws {
+        var systemError: Error?
+        let condition = NSCondition()
+
+        // Activate the condition
+        condition.lock()
+        defer { condition.unlock() }
+
+        self.packetTunnelProvider?.setTunnelNetworkSettings(networkSettings) { error in
+            systemError = error
+            condition.signal()
+        }
+
+        // Packet tunnel's `setTunnelNetworkSettings` times out in certain
+        // scenarios & never calls the given callback.
+        let setTunnelNetworkSettingsTimeout: TimeInterval = 5 // seconds
+
+        if condition.wait(until: Date().addingTimeInterval(setTunnelNetworkSettingsTimeout)) {
+            if let systemError = systemError {
+                throw WireGuardAdapterError.setNetworkSettings(systemError)
+            }
+        } else {
+            self.logHandler(.error, "setTunnelNetworkSettings timed out after 5 seconds; proceeding anyway")
+        }
+    }
+
+    /// Resolve peers of the given tunnel configuration.
+    /// - Parameter tunnelConfiguration: tunnel configuration.
+    /// - Throws: an error of type `WireGuardAdapterError`.
+    /// - Returns: The list of resolved endpoints.
+    private func resolvePeers(for tunnelConfiguration: TunnelConfiguration) throws -> [Endpoint?] {
+        let endpoints = tunnelConfiguration.peers.map { $0.endpoint }
+        let resolutionResults = DNSResolver.resolveSync(endpoints: endpoints)
+        let resolutionErrors = resolutionResults.compactMap { result -> DNSResolutionError? in
+            if case .failure(let error) = result {
+                return error
+            } else {
+                return nil
+            }
+        }
+        assert(endpoints.count == resolutionResults.count)
+        guard resolutionErrors.isEmpty else {
+            throw WireGuardAdapterError.dnsResolution(resolutionErrors)
+        }
+
+        let resolvedEndpoints = resolutionResults.map { result -> Endpoint? in
+            // swiftlint:disable:next force_try
+            return try! result?.get()
+        }
+
+        return resolvedEndpoints
+    }
+
+    /// Start WireGuard backend.
+    /// - Parameter wgConfig: WireGuard configuration
+    /// - Throws: an error of type `WireGuardAdapterError`
+    /// - Returns: tunnel handle
+    private func startWireGuardBackend(wgConfig: String) throws -> Int32 {
+        guard let tunnelFileDescriptor = self.tunnelFileDescriptor else {
+            throw WireGuardAdapterError.cannotLocateTunnelFileDescriptor
+        }
+
+        let handle = wgTurnOn(wgConfig, tunnelFileDescriptor)
+        if handle < 0 {
+            throw WireGuardAdapterError.startWireGuardBackend(handle)
+        }
+        #if os(iOS)
+        wgDisableSomeRoamingForBrokenMobileSemantics(handle)
+        #endif
+        return handle
+    }
+
+    /// Resolves the hostnames in the given tunnel configuration and return settings generator.
+    /// - Parameter tunnelConfiguration: an instance of type `TunnelConfiguration`.
+    /// - Throws: an error of type `WireGuardAdapterError`.
+    /// - Returns: an instance of type `PacketTunnelSettingsGenerator`.
+    private func makeSettingsGenerator(with tunnelConfiguration: TunnelConfiguration) throws -> PacketTunnelSettingsGenerator {
+        return PacketTunnelSettingsGenerator(
+            tunnelConfiguration: tunnelConfiguration,
+            resolvedEndpoints: try self.resolvePeers(for: tunnelConfiguration)
+        )
+    }
+
+    /// Log DNS resolution results.
+    /// - Parameter resolutionErrors: an array of type `[DNSResolutionError]`.
+    private func logEndpointResolutionResults(_ resolutionResults: [EndpointResolutionResult?]) {
+        for case .some(let result) in resolutionResults {
+            switch result {
+            case .success((let sourceEndpoint, let resolvedEndpoint)):
+                if sourceEndpoint.host == resolvedEndpoint.host {
+                    self.logHandler(.verbose, "DNS64: mapped \(sourceEndpoint.host) to itself.")
+                } else {
+                    self.logHandler(.verbose, "DNS64: mapped \(sourceEndpoint.host) to \(resolvedEndpoint.host)")
+                }
+            case .failure(let resolutionError):
+                self.logHandler(.error, "Failed to resolve endpoint \(resolutionError.address): \(resolutionError.errorDescription ?? "(nil)")")
+            }
+        }
+    }
+
+    /// Helper method used by network path monitor.
+    /// - Parameter path: new network path
+    private func didReceivePathUpdate(path: Network.NWPath) {
+        self.logHandler(.verbose, "Network change detected with \(path.status) route and interface order \(path.availableInterfaces)")
+
+        #if os(macOS)
+        if case .started(let handle, _) = self.state {
+            wgBumpSockets(handle)
+        }
+        #elseif os(iOS)
+        switch self.state {
+        case .started(let handle, let settingsGenerator):
+            if path.status.isSatisfiable {
+                let (wgConfig, resolutionResults) = settingsGenerator.endpointUapiConfiguration()
+                self.logEndpointResolutionResults(resolutionResults)
+
+                wgSetConfig(handle, wgConfig)
+                wgDisableSomeRoamingForBrokenMobileSemantics(handle)
+                wgBumpSockets(handle)
+            } else {
+                self.logHandler(.verbose, "Connectivity offline, pausing backend.")
+
+                self.state = .temporaryShutdown(settingsGenerator)
+                wgTurnOff(handle)
+            }
+
+        case .temporaryShutdown(let settingsGenerator):
+            guard path.status.isSatisfiable else { return }
+
+            self.logHandler(.verbose, "Connectivity online, resuming backend.")
+
+            do {
+                try self.setNetworkSettings(settingsGenerator.generateNetworkSettings())
+
+                let (wgConfig, resolutionResults) = settingsGenerator.uapiConfiguration()
+                self.logEndpointResolutionResults(resolutionResults)
+
+                self.state = .started(
+                    try self.startWireGuardBackend(wgConfig: wgConfig),
+                    settingsGenerator
+                )
+            } catch {
+                self.logHandler(.error, "Failed to restart backend: \(error.localizedDescription)")
+            }
+
+        case .stopped:
+            // no-op
+            break
+        }
+        #else
+        #error("Unsupported")
+        #endif
+    }
+}
+
+/// A enum describing WireGuard log levels defined in `api-apple.go`.
+public enum WireGuardLogLevel: Int32 {
+    case verbose = 0
+    case error = 1
+}
+
+private extension Network.NWPath.Status {
+    /// Returns `true` if the path is potentially satisfiable.
+    var isSatisfiable: Bool {
+        switch self {
+        case .requiresConnection, .satisfied:
+            return true
+        case .unsatisfied:
+            return false
+        @unknown default:
+            return true
+        }
+    }
+}

ios/WireGuardKit/Sources/WireGuardKitC/WireGuardKitC.h

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2023 WireGuard LLC. All Rights Reserved.
+
+#include <sys/types.h>
+#include "key.h"
+#include "x25519.h"
+
+/* From <sys/kern_control.h> */
+#define CTLIOCGINFO 0xc0644e03UL
+struct ctl_info {
+    u_int32_t   ctl_id;
+    char        ctl_name[96];
+};
+struct sockaddr_ctl {
+    u_char      sc_len;
+    u_char      sc_family;
+    u_int16_t   ss_sysaddr;
+    u_int32_t   sc_id;
+    u_int32_t   sc_unit;
+    u_int32_t   sc_reserved[5];
+};

ios/WireGuardKit/Sources/WireGuardKitC/key.c

@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is a specialized constant-time base64/hex implementation that resists side-channel attacks.
+ */
+
+#include <string.h>
+#include "key.h"
+
+static inline void encode_base64(char dest[static 4], const uint8_t src[static 3])
+{
+	const uint8_t input[] = { (src[0] >> 2) & 63, ((src[0] << 4) | (src[1] >> 4)) & 63, ((src[1] << 2) | (src[2] >> 6)) & 63, src[2] & 63 };
+
+	for (unsigned int i = 0; i < 4; ++i)
+		dest[i] = input[i] + 'A'
+			  + (((25 - input[i]) >> 8) & 6)
+			  - (((51 - input[i]) >> 8) & 75)
+			  - (((61 - input[i]) >> 8) & 15)
+			  + (((62 - input[i]) >> 8) & 3);
+
+}
+
+void key_to_base64(char base64[static WG_KEY_LEN_BASE64], const uint8_t key[static WG_KEY_LEN])
+{
+	unsigned int i;
+
+	for (i = 0; i < WG_KEY_LEN / 3; ++i)
+		encode_base64(&base64[i * 4], &key[i * 3]);
+	encode_base64(&base64[i * 4], (const uint8_t[]){ key[i * 3 + 0], key[i * 3 + 1], 0 });
+	base64[WG_KEY_LEN_BASE64 - 2] = '=';
+	base64[WG_KEY_LEN_BASE64 - 1] = '\0';
+}
+
+static inline int decode_base64(const char src[static 4])
+{
+	int val = 0;
+
+	for (unsigned int i = 0; i < 4; ++i)
+		val |= (-1
+			    + ((((('A' - 1) - src[i]) & (src[i] - ('Z' + 1))) >> 8) & (src[i] - 64))
+			    + ((((('a' - 1) - src[i]) & (src[i] - ('z' + 1))) >> 8) & (src[i] - 70))
+			    + ((((('0' - 1) - src[i]) & (src[i] - ('9' + 1))) >> 8) & (src[i] + 5))
+			    + ((((('+' - 1) - src[i]) & (src[i] - ('+' + 1))) >> 8) & 63)
+			    + ((((('/' - 1) - src[i]) & (src[i] - ('/' + 1))) >> 8) & 64)
+			) << (18 - 6 * i);
+	return val;
+}
+
+bool key_from_base64(uint8_t key[static WG_KEY_LEN], const char *base64)
+{
+	unsigned int i;
+	volatile uint8_t ret = 0;
+	int val;
+
+	if (strlen(base64) != WG_KEY_LEN_BASE64 - 1 || base64[WG_KEY_LEN_BASE64 - 2] != '=')
+		return false;
+
+	for (i = 0; i < WG_KEY_LEN / 3; ++i) {
+		val = decode_base64(&base64[i * 4]);
+		ret |= (uint32_t)val >> 31;
+		key[i * 3 + 0] = (val >> 16) & 0xff;
+		key[i * 3 + 1] = (val >> 8) & 0xff;
+		key[i * 3 + 2] = val & 0xff;
+	}
+	val = decode_base64((const char[]){ base64[i * 4 + 0], base64[i * 4 + 1], base64[i * 4 + 2], 'A' });
+	ret |= ((uint32_t)val >> 31) | (val & 0xff);
+	key[i * 3 + 0] = (val >> 16) & 0xff;
+	key[i * 3 + 1] = (val >> 8) & 0xff;
+
+	return 1 & ((ret - 1) >> 8);
+}
+
+void key_to_hex(char hex[static WG_KEY_LEN_HEX], const uint8_t key[static WG_KEY_LEN])
+{
+	unsigned int i;
+
+	for (i = 0; i < WG_KEY_LEN; ++i) {
+		hex[i * 2] = 87U + (key[i] >> 4) + ((((key[i] >> 4) - 10U) >> 8) & ~38U);
+		hex[i * 2 + 1] = 87U + (key[i] & 0xf) + ((((key[i] & 0xf) - 10U) >> 8) & ~38U);
+	}
+	hex[i * 2] = '\0';
+}
+
+bool key_from_hex(uint8_t key[static WG_KEY_LEN], const char *hex)
+{
+	uint8_t c, c_acc, c_alpha0, c_alpha, c_num0, c_num, c_val;
+	volatile uint8_t ret = 0;
+
+	if (strlen(hex) != WG_KEY_LEN_HEX - 1)
+		return false;
+
+	for (unsigned int i = 0; i < WG_KEY_LEN_HEX - 1; i += 2) {
+		c = (uint8_t)hex[i];
+		c_num = c ^ 48U;
+		c_num0 = (c_num - 10U) >> 8;
+		c_alpha = (c & ~32U) - 55U;
+		c_alpha0 = ((c_alpha - 10U) ^ (c_alpha - 16U)) >> 8;
+		ret |= ((c_num0 | c_alpha0) - 1) >> 8;
+		c_val = (c_num0 & c_num) | (c_alpha0 & c_alpha);
+		c_acc = c_val * 16U;
+
+		c = (uint8_t)hex[i + 1];
+		c_num = c ^ 48U;
+		c_num0 = (c_num - 10U) >> 8;
+		c_alpha = (c & ~32U) - 55U;
+		c_alpha0 = ((c_alpha - 10U) ^ (c_alpha - 16U)) >> 8;
+		ret |= ((c_num0 | c_alpha0) - 1) >> 8;
+		c_val = (c_num0 & c_num) | (c_alpha0 & c_alpha);
+		key[i / 2] = c_acc | c_val;
+	}
+
+	return 1 & ((ret - 1) >> 8);
+}
+
+bool key_eq(const uint8_t key1[static WG_KEY_LEN], const uint8_t key2[static WG_KEY_LEN])
+{
+	volatile uint8_t acc = 0;
+	for (unsigned int i = 0; i < WG_KEY_LEN; ++i) {
+		acc |= key1[i] ^ key2[i];
+		asm volatile("" : "=r"(acc) : "0"(acc));
+	}
+	return 1 & ((acc - 1) >> 8);
+}

ios/WireGuardKit/Sources/WireGuardKitC/key.h

@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#ifndef KEY_H
+#define KEY_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define WG_KEY_LEN (32)
+#define WG_KEY_LEN_BASE64 (45)
+#define WG_KEY_LEN_HEX (65)
+
+void key_to_base64(char base64[static WG_KEY_LEN_BASE64], const uint8_t key[static WG_KEY_LEN]);
+bool key_from_base64(uint8_t key[static WG_KEY_LEN], const char *base64);
+
+void key_to_hex(char hex[static WG_KEY_LEN_HEX], const uint8_t key[static WG_KEY_LEN]);
+bool key_from_hex(uint8_t key[static WG_KEY_LEN], const char *hex);
+
+bool key_eq(const uint8_t key1[static WG_KEY_LEN], const uint8_t key2[static WG_KEY_LEN]);
+
+#endif

ios/WireGuardKit/Sources/WireGuardKitC/module.modulemap

@@ -0,0 +1,4 @@
+module WireGuardKitC {
+    umbrella header "WireGuardKitC.h"
+    export *
+}

ios/WireGuardKit/Sources/WireGuardKitC/x25519.c

@@ -0,0 +1,178 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * Curve25519 ECDH functions, based on TweetNaCl but cleaned up.
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <assert.h>
+#include <CommonCrypto/CommonRandom.h>
+
+#include "x25519.h"
+
+typedef int64_t fe[16];
+
+static inline void carry(fe o)
+{
+    int i;
+
+    for (i = 0; i < 16; ++i) {
+        o[(i + 1) % 16] += (i == 15 ? 38 : 1) * (o[i] >> 16);
+        o[i] &= 0xffff;
+    }
+}
+
+static inline void cswap(fe p, fe q, int b)
+{
+    int i;
+    int64_t t, c = ~(b - 1);
+
+    for (i = 0; i < 16; ++i) {
+        t = c & (p[i] ^ q[i]);
+        p[i] ^= t;
+        q[i] ^= t;
+    }
+}
+
+static inline void pack(uint8_t *o, const fe n)
+{
+    int i, j, b;
+    fe m, t;
+
+    memcpy(t, n, sizeof(t));
+    carry(t);
+    carry(t);
+    carry(t);
+    for (j = 0; j < 2; ++j) {
+        m[0] = t[0] - 0xffed;
+        for (i = 1; i < 15; ++i) {
+            m[i] = t[i] - 0xffff - ((m[i - 1] >> 16) & 1);
+            m[i - 1] &= 0xffff;
+        }
+        m[15] = t[15] - 0x7fff - ((m[14] >> 16) & 1);
+        b = (m[15] >> 16) & 1;
+        m[14] &= 0xffff;
+        cswap(t, m, 1 - b);
+    }
+    for (i = 0; i < 16; ++i) {
+        o[2 * i] = t[i] & 0xff;
+        o[2 * i + 1] = t[i] >> 8;
+    }
+}
+
+static inline void unpack(fe o, const uint8_t *n)
+{
+    int i;
+
+    for (i = 0; i < 16; ++i)
+        o[i] = n[2 * i] + ((int64_t)n[2 * i + 1] << 8);
+    o[15] &= 0x7fff;
+}
+
+static inline void add(fe o, const fe a, const fe b)
+{
+    int i;
+
+    for (i = 0; i < 16; ++i)
+        o[i] = a[i] + b[i];
+}
+
+static inline void subtract(fe o, const fe a, const fe b)
+{
+    int i;
+
+    for (i = 0; i < 16; ++i)
+        o[i] = a[i] - b[i];
+}
+
+static inline void multmod(fe o, const fe a, const fe b)
+{
+    int i, j;
+    int64_t t[31] = { 0 };
+
+    for (i = 0; i < 16; ++i) {
+        for (j = 0; j < 16; ++j)
+            t[i + j] += a[i] * b[j];
+    }
+    for (i = 0; i < 15; ++i)
+        t[i] += 38 * t[i + 16];
+    memcpy(o, t, sizeof(fe));
+    carry(o);
+    carry(o);
+}
+
+static inline void invert(fe o, const fe i)
+{
+    fe c;
+    int a;
+
+    memcpy(c, i, sizeof(c));
+    for (a = 253; a >= 0; --a) {
+        multmod(c, c, c);
+        if (a != 2 && a != 4)
+            multmod(c, c, i);
+    }
+    memcpy(o, c, sizeof(fe));
+}
+
+static void curve25519_shared_secret(uint8_t shared_secret[32], const uint8_t private_key[32], const uint8_t public_key[32])
+{
+    static const fe a24 = { 0xdb41, 1 };
+    uint8_t z[32];
+    int64_t r;
+    int i;
+    fe a = { 1 }, b, c = { 0 }, d = { 1 }, e, f, x;
+
+    memcpy(z, private_key, sizeof(z));
+
+    z[31] = (z[31] & 127) | 64;
+    z[0] &= 248;
+
+    unpack(x, public_key);
+    memcpy(b, x, sizeof(b));
+
+    for (i = 254; i >= 0; --i) {
+        r = (z[i >> 3] >> (i & 7)) & 1;
+        cswap(a, b, (int)r);
+        cswap(c, d, (int)r);
+        add(e, a, c);
+        subtract(a, a, c);
+        add(c, b, d);
+        subtract(b, b, d);
+        multmod(d, e, e);
+        multmod(f, a, a);
+        multmod(a, c, a);
+        multmod(c, b, e);
+        add(e, a, c);
+        subtract(a, a, c);
+        multmod(b, a, a);
+        subtract(c, d, f);
+        multmod(a, c, a24);
+        add(a, a, d);
+        multmod(c, c, a);
+        multmod(a, d, f);
+        multmod(d, b, x);
+        multmod(b, e, e);
+        cswap(a, b, (int)r);
+        cswap(c, d, (int)r);
+    }
+    invert(c, c);
+    multmod(a, a, c);
+    pack(shared_secret, a);
+}
+
+void curve25519_derive_public_key(uint8_t public_key[32], const uint8_t private_key[32])
+{
+    static const uint8_t basepoint[32] = { 9 };
+
+    curve25519_shared_secret(public_key, private_key, basepoint);
+}
+
+void curve25519_generate_private_key(uint8_t private_key[32])
+{
+    assert(CCRandomGenerateBytes(private_key, 32) == kCCSuccess);
+    private_key[31] = (private_key[31] & 127) | 64;
+    private_key[0] &= 248;
+}

ios/WireGuardKit/Sources/WireGuardKitC/x25519.h

@@ -0,0 +1,7 @@
+#ifndef X25519_H
+#define X25519_H
+
+void curve25519_derive_public_key(unsigned char public_key[32], const unsigned char private_key[32]);
+void curve25519_generate_private_key(unsigned char private_key[32]);
+
+#endif

ios/WireGuardKit/Sources/WireGuardKitGo/dummy.c

@@ -0,0 +1 @@
+// Empty

ios/WireGuardKit/Sources/WireGuardKitGo/module.modulemap

@@ -0,0 +1,5 @@
+module WireGuardKitGo {
+    umbrella header "wireguard.h"
+    link "wg-go"
+    export *
+}

ios/WireGuardKit/Sources/WireGuardKitGo/wireguard.h

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2018-2023 WireGuard LLC. All Rights Reserved.
+ */
+
+#ifndef WIREGUARD_H
+#define WIREGUARD_H
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef void(*logger_fn_t)(void *context, int level, const char *msg);
+extern void wgSetLogger(void *context, logger_fn_t logger_fn);
+extern int wgTurnOn(const char *settings, int32_t tun_fd);
+extern void wgTurnOff(int handle);
+extern int64_t wgSetConfig(int handle, const char *settings);
+extern char *wgGetConfig(int handle);
+extern void wgBumpSockets(int handle);
+extern void wgDisableSomeRoamingForBrokenMobileSemantics(int handle);
+extern const char *wgVersion();
+
+#endif