feat(xep): Begin work on SASL2

packages/moxxmpp/lib/moxxmpp.dart

@@ -23,6 +23,7 @@ export 'package:moxxmpp/src/negotiators/sasl/errors.dart';
 export 'package:moxxmpp/src/negotiators/sasl/negotiator.dart';
 export 'package:moxxmpp/src/negotiators/sasl/plain.dart';
 export 'package:moxxmpp/src/negotiators/sasl/scram.dart';
+export 'package:moxxmpp/src/negotiators/sasl2.dart';
 export 'package:moxxmpp/src/negotiators/starttls.dart';
 export 'package:moxxmpp/src/ping.dart';
 export 'package:moxxmpp/src/presence.dart';

packages/moxxmpp/lib/src/connection.dart

@@ -254,7 +254,8 @@ class XmppConnection {
   }
 
   /// Register a list of negotiator with the connection.
-  void registerFeatureNegotiators(List<XmppFeatureNegotiatorBase> negotiators) {
+  Future<void> registerFeatureNegotiators(
+      List<XmppFeatureNegotiatorBase> negotiators) async {
     for (final negotiator in negotiators) {
       _log.finest('Registering ${negotiator.id}');
       negotiator.register(
@@ -273,6 +274,10 @@ class XmppConnection {
     }
 
     _log.finest('Negotiators registered');
+
+    for (final negotiator in _featureNegotiators.values) {
+      await negotiator.postRegisterCallback();
+    }
   }
 
   /// Reset all registered negotiators.

packages/moxxmpp/lib/src/namespaces.dart

@@ -116,6 +116,9 @@ const omemoBundlesXmlns = 'urn:xmpp:omemo:2:bundles';
 // XEP-0385
 const simsXmlns = 'urn:xmpp:sims:1';
 
+// XEP-0388
+const sasl2Xmlns = 'urn:xmpp:sasl:2';
+
 // XEP-0420
 const sceXmlns = 'urn:xmpp:sce:1';
 

packages/moxxmpp/lib/src/negotiators/namespaces.dart

@@ -7,3 +7,4 @@ const rosterNegotiator = 'im.moxxmpp.core.roster';
 const resourceBindingNegotiator = 'im.moxxmpp.core.resource';
 const streamManagementNegotiator = 'im.moxxmpp.xeps.sm';
 const startTlsNegotiator = 'im.moxxmpp.core.starttls';
+const sasl2Negotiator = 'org.moxxmpp.sasl.sasl2';

packages/moxxmpp/lib/src/negotiators/negotiator.dart

@@ -1,3 +1,4 @@
+import 'package:meta/meta.dart';
 import 'package:moxlib/moxlib.dart';
 import 'package:moxxmpp/src/errors.dart';
 import 'package:moxxmpp/src/events.dart';
@@ -120,5 +121,11 @@ abstract class XmppFeatureNegotiatorBase {
     state = NegotiatorState.ready;
   }
 
+  @protected
   NegotiatorAttributes get attributes => _attributes;
+
+  /// Run after all negotiators are registered. Useful for registering callbacks against
+  /// other negotiators.
+  @visibleForOverriding
+  Future<void> postRegisterCallback() async {}
 }

packages/moxxmpp/lib/src/negotiators/sasl/plain.dart

@@ -6,6 +6,7 @@ import 'package:moxxmpp/src/negotiators/negotiator.dart';
 import 'package:moxxmpp/src/negotiators/sasl/errors.dart';
 import 'package:moxxmpp/src/negotiators/sasl/negotiator.dart';
 import 'package:moxxmpp/src/negotiators/sasl/nonza.dart';
+import 'package:moxxmpp/src/negotiators/sasl2.dart';
 import 'package:moxxmpp/src/stringxml.dart';
 import 'package:moxxmpp/src/types/result.dart';
 
@@ -76,4 +77,11 @@ class SaslPlainNegotiator extends SaslNegotiator {
 
     super.reset();
   }
+
+  @override
+  Future<void> postRegisterCallback() async {
+    attributes
+        .getNegotiatorById<Sasl2Negotiator>(sasl2Negotiator)
+        ?.registerSaslNegotiator(this);
+  }
 }

packages/moxxmpp/lib/src/negotiators/sasl2.dart

@@ -0,0 +1,161 @@
+import 'package:moxxmpp/src/namespaces.dart';
+import 'package:moxxmpp/src/negotiators/namespaces.dart';
+import 'package:moxxmpp/src/negotiators/negotiator.dart';
+import 'package:moxxmpp/src/negotiators/sasl/negotiator.dart';
+import 'package:moxxmpp/src/stringxml.dart';
+import 'package:moxxmpp/src/types/result.dart';
+
+typedef Sasl2FeaturesReceivedCallback = Future<List<XMLNode>> Function(XMLNode);
+
+class NoSASLMechanismSelectedError extends NegotiatorError {
+  @override
+  bool isRecoverable() => false;
+}
+
+/// A data class describing the user agent. See https://dyn.eightysoft.de/final/xep-0388.html#initiation
+class UserAgent {
+  const UserAgent({
+    this.id,
+    this.software,
+    this.device,
+  });
+
+  /// The identifier of the software/device combo connecting. SHOULD be a UUIDv4.
+  final String? id;
+
+  /// The software's name that's connecting at the moment.
+  final String? software;
+
+  /// The name of the device.
+  final String? device;
+
+  XMLNode toXml() {
+    assert(id != null || software != null || device != null,
+        'A completely empty user agent makes no sense');
+    return XMLNode(
+      tag: 'user-agent',
+      attributes: id != null
+          ? {
+              'id': id,
+            }
+          : {},
+      children: [
+        if (software != null)
+          XMLNode(
+            tag: 'software',
+            text: software,
+          ),
+        if (device != null)
+          XMLNode(
+            tag: 'device',
+            text: device,
+          ),
+      ],
+    );
+  }
+}
+
+enum Sasl2State {
+  // No request has been sent yet.
+  idle,
+}
+
+/// A negotiator that implements XEP-0388 SASL2. Alone, it does nothing. Has to be
+/// registered with other negotiators that register themselves against this one.
+class Sasl2Negotiator extends XmppFeatureNegotiatorBase {
+  Sasl2Negotiator({
+    this.userAgent,
+  }) : super(100, false, sasl2Xmlns, sasl2Negotiator);
+
+  /// The user agent data that will be sent to the server when authenticating.
+  final UserAgent? userAgent;
+
+  /// List of callbacks that are registered against us. Will be called once we get
+  /// SASL2 features.
+  final List<Sasl2FeaturesReceivedCallback> _featureCallbacks =
+      List<Sasl2FeaturesReceivedCallback>.empty(growable: true);
+
+  /// List of SASL negotiators, sorted by their priority. The higher the priority, the
+  /// lower its index.
+  final List<SaslNegotiator> _saslNegotiators =
+      List<SaslNegotiator>.empty(growable: true);
+
+  /// The state the SASL2 negotiator is currently in.
+  Sasl2State _sasl2State = Sasl2State.idle;
+
+  /// The SASL negotiator that will negotiate authentication.
+  SaslNegotiator? _currentSaslNegotiator;
+
+  void registerSaslNegotiator(SaslNegotiator negotiator) {
+    _saslNegotiators
+      ..add(negotiator)
+      ..sort((a, b) => b.priority.compareTo(a.priority));
+  }
+
+  void registerFeaturesCallback(Sasl2FeaturesReceivedCallback callback) {
+    _featureCallbacks.add(callback);
+  }
+
+  @override
+  Future<Result<NegotiatorState, NegotiatorError>> negotiate(
+      XMLNode nonza) async {
+    switch (_sasl2State) {
+      case Sasl2State.idle:
+        final sasl2 = nonza.firstTag('authentication', xmlns: sasl2Xmlns)!;
+        final mechanisms = XMLNode.xmlns(
+          tag: 'mechanisms',
+          xmlns: saslXmlns,
+          children: sasl2.children.where((c) => c.tag == 'mechanism').toList(),
+        );
+        for (final negotiator in _saslNegotiators) {
+          if (negotiator.matchesFeature([mechanisms])) {
+            _currentSaslNegotiator = negotiator;
+            break;
+          }
+        }
+
+        // We must have a SASL negotiator by now
+        if (_currentSaslNegotiator == null) {
+          return Result(NoSASLMechanismSelectedError());
+        }
+
+        // Collect additional data by interested negotiators
+        final children = List<XMLNode>.empty(growable: true);
+        for (final callback in _featureCallbacks) {
+          children.addAll(
+            await callback(sasl2),
+          );
+        }
+
+        // Build the authenticate nonza
+        final authenticate = XMLNode.xmlns(
+          tag: 'authenticate',
+          xmlns: sasl2Xmlns,
+          attributes: {
+            'mechanism': _currentSaslNegotiator!.mechanismName,
+          },
+          children: [
+            if (userAgent != null) userAgent!.toXml(),
+
+            // TODO: Get the initial response
+            XMLNode(
+              tag: 'initial-response',
+            ),
+            ...children,
+          ],
+        );
+        attributes.sendNonza(authenticate);
+        return const Result(NegotiatorState.ready);
+    }
+
+    return const Result(NegotiatorState.ready);
+  }
+
+  @override
+  void reset() {
+    _currentSaslNegotiator = null;
+    _sasl2State = Sasl2State.idle;
+
+    super.reset();
+  }
+}

packages/moxxmpp/test/xeps/xep_0030_test.dart

@@ -84,7 +84,7 @@ void main() {
       DiscoManager([]),
       EntityCapabilitiesManager('http://moxxmpp.example'),
     ]);
-    conn.registerFeatureNegotiators([
+    await conn.registerFeatureNegotiators([
       SaslPlainNegotiator(),
       SaslScramNegotiator(10, '', '', ScramHashType.sha512),
       ResourceBindingNegotiator(),

packages/moxxmpp/test/xeps/xep_0060_test.dart

@@ -169,12 +169,11 @@ void main() {
       MessageManager(),
       RosterManager(TestingRosterStateManager(null, [])),
     ]);
-    connection
-      ..registerFeatureNegotiators([
+    await connection.registerFeatureNegotiators([
       SaslPlainNegotiator(),
       ResourceBindingNegotiator(),
-      ])
-      ..setConnectionSettings(TestingManagerHolder.settings);
+    ]);
+    connection.setConnectionSettings(TestingManagerHolder.settings);
     await connection.connect(
       waitUntilLogin: true,
     );

packages/moxxmpp/test/xeps/xep_0198_test.dart

@@ -298,7 +298,7 @@ void main() {
         CarbonsManager()..forceEnable(),
         EntityCapabilitiesManager('http://moxxmpp.example'),
       ]);
-      conn.registerFeatureNegotiators([
+      await conn.registerFeatureNegotiators([
         SaslPlainNegotiator(),
         ResourceBindingNegotiator(),
         StreamManagementNegotiator(),
@@ -423,7 +423,7 @@ void main() {
         CarbonsManager()..forceEnable(),
         //EntityCapabilitiesManager('http://moxxmpp.example'),
       ]);
-      conn.registerFeatureNegotiators([
+      await conn.registerFeatureNegotiators([
         SaslPlainNegotiator(),
         ResourceBindingNegotiator(),
         StreamManagementNegotiator(),
@@ -580,7 +580,7 @@ void main() {
         DiscoManager([]),
         StreamManagementManager(),
       ]);
-      conn.registerFeatureNegotiators([
+      await conn.registerFeatureNegotiators([
         SaslPlainNegotiator(),
         ResourceBindingNegotiator(),
         StreamManagementNegotiator(),
@@ -674,7 +674,7 @@ void main() {
         DiscoManager([]),
         StreamManagementManager(),
       ]);
-      conn.registerFeatureNegotiators([
+      await conn.registerFeatureNegotiators([
         SaslPlainNegotiator(),
         ResourceBindingNegotiator(),
         StreamManagementNegotiator(),
@@ -765,7 +765,7 @@ void main() {
         DiscoManager([]),
         StreamManagementManager(),
       ]);
-      conn.registerFeatureNegotiators([
+      await conn.registerFeatureNegotiators([
         SaslPlainNegotiator(),
         ResourceBindingNegotiator(),
         StreamManagementNegotiator(),

packages/moxxmpp/test/xeps/xep_0388_test.dart

@@ -0,0 +1,69 @@
+import 'package:moxxmpp/moxxmpp.dart';
+import 'package:test/test.dart';
+import '../helpers/logging.dart';
+import '../helpers/xmpp.dart';
+
+void main() {
+  initLogger();
+
+  test('Test simple SASL2 negotiation', () async {
+    final fakeSocket = StubTCPSocket([
+      StringExpectation(
+        "<stream:stream xmlns='jabber:client' version='1.0' xmlns:stream='http://etherx.jabber.org/streams' to='test.server' xml:lang='en'>",
+        '''
+<stream:stream
+    xmlns="jabber:client"
+    version="1.0"
+    xmlns:stream="http://etherx.jabber.org/streams"
+    from="test.server"
+    xml:lang="en">
+  <stream:features xmlns="http://etherx.jabber.org/streams">
+    <mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
+      <mechanism>PLAIN</mechanism>
+    </mechanisms>
+    <authentication xmlns='urn:xmpp:sasl:2'>
+      <mechanism>PLAIN</mechanism>
+    </authentication>
+  </stream:features>''',
+      ),
+      StanzaExpectation(
+        "<authenticate xmlns='urn:xmpp:sasl:2' mechanism='PLAIN'><user-agent id='d4565fa7-4d72-4749-b3d3-740edbf87770'><software>moxxmpp</software><device>PapaTutuWawa's awesome device</device></user-agent><initial-response>AHBvbHlub21kaXZpc2lvbgBhYWFh</initial-response></authenticate>",
+        '',
+      ),
+    ]);
+    final conn = XmppConnection(
+      TestingReconnectionPolicy(),
+      AlwaysConnectedConnectivityManager(),
+      fakeSocket,
+    )..setConnectionSettings(
+        ConnectionSettings(
+          jid: JID.fromString('polynomdivision@test.server'),
+          password: 'aaaa',
+          useDirectTLS: true,
+        ),
+      );
+    await conn.registerManagers([
+      PresenceManager(),
+      RosterManager(TestingRosterStateManager('', [])),
+      DiscoManager([]),
+    ]);
+    await conn.registerFeatureNegotiators([
+      SaslPlainNegotiator(),
+      ResourceBindingNegotiator(),
+      Sasl2Negotiator(
+        userAgent: const UserAgent(
+          id: 'd4565fa7-4d72-4749-b3d3-740edbf87770',
+          software: 'moxxmpp',
+          device: "PapaTutuWawa's awesome device",
+        ),
+      ),
+    ]);
+
+    final result = await conn.connect(
+      waitUntilLogin: true,
+      shouldReconnect: false,
+      enableReconnectOnSuccess: false,
+    );
+    expect(result.isType<XmppError>(), false);
+  });
+}

packages/moxxmpp/test/xmpp_test.dart

@@ -140,7 +140,7 @@ void main() {
       StreamManagementManager(),
       EntityCapabilitiesManager('http://moxxmpp.example'),
     ]);
-    conn.registerFeatureNegotiators([
+    await conn.registerFeatureNegotiators([
       SaslPlainNegotiator(),
       SaslScramNegotiator(10, '', '', ScramHashType.sha512),
       ResourceBindingNegotiator(),
@@ -195,7 +195,7 @@ void main() {
       DiscoManager([]),
       EntityCapabilitiesManager('http://moxxmpp.example'),
     ]);
-    conn.registerFeatureNegotiators([
+    await conn.registerFeatureNegotiators([
       SaslPlainNegotiator(),
     ]);
 
@@ -254,7 +254,7 @@ void main() {
       DiscoManager([]),
       EntityCapabilitiesManager('http://moxxmpp.example'),
     ]);
-    conn.registerFeatureNegotiators([SaslPlainNegotiator()]);
+    await conn.registerFeatureNegotiators([SaslPlainNegotiator()]);
 
     conn.asBroadcastStream().listen((event) {
       if (event is AuthenticationFailedEvent &&
@@ -407,12 +407,11 @@ void main() {
       RosterManager(TestingRosterStateManager('', [])),
       DiscoManager([]),
     ]);
-    conn
-      ..registerFeatureNegotiators([
+    await conn.registerFeatureNegotiators([
       // SaslPlainNegotiator(),
       ResourceBindingNegotiator(),
-      ])
-      ..setConnectionSettings(
+    ]);
+    conn.setConnectionSettings(
       ConnectionSettings(
         jid: JID.fromString('testuser@example.org'),
         password: 'abc123',