Add system client as option for transport type

Author: ecnepsnai

Sources/DNSKit/Clients/SystemClient.swift

@@ -0,0 +1,53 @@
+// DNSKit
+// Copyright (C) Ian Spence and other DNSKit Contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import Foundation
+import Network
+
+internal final class SystemClient: IClient {
+    private let dispatchQueue: DispatchQueue
+
+    init(address: String, transportOptions: TransportOptions) throws {
+        self.dispatchQueue = DispatchQueue(label: "io.ecn.dnskit.systemclient", qos: .userInitiated)
+    }
+
+    func send(message: Message, complete: @escaping @Sendable (Result<Response, DNSKitError>) -> Void) {
+        self.dispatchQueue.async {
+            do {
+                let timer = Timer.start()
+                let reply = try SystemResolver.query(question: message.questions[0], dnssecOk: message.dnssecOK)
+                complete(.success(.init(message: reply, serverAddress: nil, elapsed: timer.stop())))
+            } catch {
+                if let error = error as? DNSKitError {
+                    complete(.failure(error))
+                } else {
+                    complete(.failure(.internalError("\(error)")))
+                }
+            }
+        }
+    }
+
+    func authenticate(message: Message, complete: @escaping @Sendable (Result<DNSSECResult, any Error>) -> Void) {
+        self.dispatchQueue.async {
+            do {
+                let result = try SystemResolver.authenticate(message: message)
+                complete(.success(result))
+            } catch {
+                complete(.failure(error))
+            }
+        }
+    }
+}

Sources/DNSKit/Docs.docc/index.md

@@ -6,6 +6,7 @@ DNSKit provides a wide array of support across the DNS ecosystem, including:
 
 - Native support for most common DNS record types.
 - Support for DNS over HTTPS, DNS over TLS, DNS over Quic, and traditional DNS using TCP or UDP.
+- Bridge for using the system resolver in Swift (libresolv bridge)
 - Full DNSSEC signature validation & chain trust establishment.
 - WHOIS client for domain information.
 
@@ -22,3 +23,7 @@ Use the ``WHOISClient/lookup(_:)`` class to perform WHOIS lookups
 
 Re-using the same query you used to perform your query, call ``Query/authenticate(message:)``. Be sure that ``QueryOptions/dnssecRequested``
 was set to true in your original query.
+
+### System Resolver
+
+To utilize the System's resolver, use the ``SystemResolver/query(question:dnssecOk:)`` method.

Sources/DNSKit/Query.swift

@@ -148,6 +148,8 @@ public final class Query: Sendable {
                 } else {
                     fatalError("Attempted to use quic on unsupported target")
                 }
+            case .System:
+                clients.append(try SystemClient(address: serverAddress, transportOptions: transportOptions))
             }
         }
 
@@ -264,6 +266,8 @@ public final class Query: Sendable {
                     } else {
                         fatalError("Attempted to use quic on unsupported target")
                     }
+                case .System:
+                    _ = try SystemClient(address: serverAddress, transportOptions: TransportOptions())
                 }
             }
             return nil

Sources/DNSKit/Types.swift

@@ -95,6 +95,11 @@ public enum TransportType: String, Codable, CaseIterable, Sendable {
     ///
     /// Expects the server address to be an IPv4 or IPv6 address with optional port, defaulting to 853.
     case QUIC = "quic"
+    /// Special transport type to indicate to use the system's DNS resolver.
+    ///
+    /// When using this option in ``Query/init(transportType:transportOptions:serverAddresses:recordType:name:queryOptions:)``
+    /// the `serverAddresses` and `transportOptions` values are ingored.
+    case System = "system"
 
     public func string() -> String {
         return String(describing: self)

Tests/DNSKitTests/ClientTests.swift

@@ -52,6 +52,8 @@ final class ClientTests {
             } else {
                 fatalError("Attempted to use Quic client on unsupported platform")
             }
+        case .System:
+            self.client = try SystemClient(address: serverAddress, transportOptions: transportOptions)
         }
     }
 

Tests/DNSKitTests/SystemClientTests.swift

@@ -0,0 +1,72 @@
+// DNSKit
+// Copyright (C) Ian Spence and other DNSKit Contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import XCTest
+@testable import DNSKit
+
+final class SystemClientTests: XCTestCase, IClientTests {
+    func testQuery() async throws {
+        try await ClientTests(transportType: .System, serverAddress: "").testQuery()
+    }
+
+    func testPTRQuery() async throws {
+        try await ClientTests(transportType: .System, serverAddress: "").testPTRQuery()
+    }
+
+    func testQueryNXDOMAIN() async throws {
+        try await ClientTests(transportType: .System, serverAddress: "").testQueryNXDOMAIN()
+    }
+
+    func testAuthenticateMessageA() async throws {
+        try await ClientTests(transportType: .System, serverAddress: "").testAuthenticateMessageA()
+    }
+
+    func testAuthenticateMessageSOA() async throws {
+        try await ClientTests(transportType: .System, serverAddress: "").testAuthenticateMessageSOA()
+    }
+
+    func testAuthenticateRoot() async throws {
+        try await ClientTests(transportType: .System, serverAddress: "").testAuthenticateRoot()
+    }
+
+    func testAuthenticateTLD() async throws {
+        try await ClientTests(transportType: .System, serverAddress: "").testAuthenticateTLD()
+    }
+
+    func testAuthenticateCNAME() async throws {
+        try await ClientTests(transportType: .System, serverAddress: "").testAuthenticateCNAME()
+    }
+
+    func testLocalControl() async throws {
+        // Test does not apply
+    }
+
+    func testLocalRandomData() async throws {
+        // Test does not apply
+    }
+
+    func testLocalLengthOver() async throws {
+        // Test does not apply
+    }
+
+    func testLocalLengthUnder() async throws {
+        // Test does not apply
+    }
+
+    func testLocalAQueryInvalidAddress() async throws {
+        // Test does not apply
+    }
+}