AdvancedBlocking: updated implementation to use new IDnsRequestBlockingHandler interface. Added feature to select group based on DNS server local end point.

Apps/AdvancedBlockingApp/App.cs

@@ -39,7 +39,7 @@ using TechnitiumLibrary.Net.Http.Client;
 
 namespace AdvancedBlocking
 {
-    public sealed class App : IDnsApplication, IDnsAuthoritativeRequestHandler
+    public sealed class App : IDnsApplication, IDnsRequestBlockingHandler
     {
         #region variables
 
@@ -51,6 +51,7 @@ namespace AdvancedBlocking
         bool _enableBlocking;
         int _blockListUrlUpdateIntervalHours;
 
+        IReadOnlyDictionary<IPEndPoint, string> _localEndPointGroupMap;
         IReadOnlyDictionary<NetworkAddress, string> _networkGroupMap;
         IReadOnlyDictionary<string, Group> _groups;
 
@@ -242,11 +243,45 @@ namespace AdvancedBlocking
             return false;
         }
 
+        private string GetGroupName(DnsDatagram request, IPEndPoint remoteEP)
+        {
+            if ((request.Metadata is not null) && (request.Metadata.NameServer is not null))
+            {
+                IPEndPoint requestLocalEP = request.Metadata.NameServer.IPEndPoint;
+                if (requestLocalEP is not null)
+                {
+                    foreach (KeyValuePair<IPEndPoint, string> entry in _localEndPointGroupMap)
+                    {
+                        if ((entry.Key.Port == 0) && entry.Key.Address.Equals(requestLocalEP.Address))
+                            return entry.Value;
+
+                        if (entry.Key.Equals(requestLocalEP))
+                            return entry.Value;
+                    }
+                }
+            }
+
+            string groupName = null;
+            IPAddress remoteIP = remoteEP.Address;
+            NetworkAddress network = null;
+
+            foreach (KeyValuePair<NetworkAddress, string> entry in _networkGroupMap)
+            {
+                if (entry.Key.Contains(remoteIP) && ((network is null) || (entry.Key.PrefixLength > network.PrefixLength)))
+                {
+                    network = entry.Key;
+                    groupName = entry.Value;
+                }
+            }
+
+            return groupName;
+        }
+
         #endregion
 
         #region public
 
-        public Task InitializeAsync(IDnsServer dnsServer, string config)
+        public async Task InitializeAsync(IDnsServer dnsServer, string config)
         {
             _dnsServer = dnsServer;
 
@@ -261,6 +296,19 @@ namespace AdvancedBlocking
             _enableBlocking = jsonConfig.GetProperty("enableBlocking").GetBoolean();
             _blockListUrlUpdateIntervalHours = jsonConfig.GetProperty("blockListUrlUpdateIntervalHours").GetInt32();
 
+            if (jsonConfig.TryReadObjectAsMap("localEndPointGroupMap",
+                delegate (string localEP, JsonElement jsonGroup)
+                {
+                    if (!IPEndPoint.TryParse(localEP, out IPEndPoint ep))
+                        throw new InvalidOperationException("Local end point group map contains an invalid end point: " + localEP);
+
+                    return new Tuple<IPEndPoint, string>(ep, jsonGroup.GetString());
+                },
+                out Dictionary<IPEndPoint, string> localEndPointGroupMap))
+            {
+                _localEndPointGroupMap = localEndPointGroupMap;
+            }
+
             _networkGroupMap = jsonConfig.ReadObjectAsMap("networkGroupMap", delegate (string network, JsonElement jsonGroup)
             {
                 if (!NetworkAddress.TryParse(network, out NetworkAddress networkAddress))
@@ -355,7 +403,7 @@ namespace AdvancedBlocking
                 _dnsServer.WriteLog("Advanced Blocking app loaded all zones successfully for group: " + group.Key);
             }
 
-            Task.Run(async delegate ()
+            await Task.Run(async delegate ()
             {
                 List<Task> loadTasks = new List<Task>();
 
@@ -417,52 +465,41 @@ namespace AdvancedBlocking
                 }
             });
 
-            return Task.CompletedTask;
+            if (!jsonConfig.TryGetProperty("localEndPointGroupMap", out _))
+            {
+                config = config.Replace("\"networkGroupMap\"", "\"localEndPointGroupMap\": {\r\n  },\r\n  \"networkGroupMap\"");
+
+                await File.WriteAllTextAsync(Path.Combine(dnsServer.ApplicationFolder, "dnsApp.config"), config);
+            }
         }
 
-        public async Task<DnsDatagram> ProcessRequestAsync(DnsDatagram request, IPEndPoint remoteEP, DnsTransportProtocol protocol, bool isRecursionAllowed)
+        public Task<bool> IsAllowedAsync(DnsDatagram request, IPEndPoint remoteEP)
         {
             if (!_enableBlocking)
-                return null;
-
-            IPAddress remoteIP = remoteEP.Address;
-            NetworkAddress network = null;
-            string groupName = null;
-
-            foreach (KeyValuePair<NetworkAddress, string> entry in _networkGroupMap)
-            {
-                if (entry.Key.Contains(remoteIP) && ((network is null) || (entry.Key.PrefixLength > network.PrefixLength)))
-                {
-                    network = entry.Key;
-                    groupName = entry.Value;
-                }
-            }
+                return Task.FromResult(false);
 
+            string groupName = GetGroupName(request, remoteEP);
             if ((groupName is null) || !_groups.TryGetValue(groupName, out Group group) || !group.EnableBlocking)
-                return null;
+                return Task.FromResult(false);
 
             DnsQuestionRecord question = request.Question[0];
 
-            if (!group.IsZoneBlocked(question.Name, out bool allowed, out string blockedDomain, out string blockedRegex, out Uri blockListUrl))
-            {
-                if (allowed)
-                {
-                    try
-                    {
-                        DnsDatagram internalResponse = await _dnsServer.DirectQueryAsync(request);
-                        if (internalResponse.Tag is null)
-                            internalResponse.Tag = DnsServerResponseType.Recursive;
+            return Task.FromResult(group.IsZoneAllowed(question.Name));
+        }
 
-                        return internalResponse;
-                    }
-                    catch (Exception ex)
-                    {
-                        _dnsServer.WriteLog("Failed to resolve the request for allowed domain name with QNAME: " + question.Name + "; QTYPE: " + question.Type + "; QCLASS: " + question.Class + "\r\n" + ex.ToString());
-                    }
-                }
+        public Task<DnsDatagram> ProcessRequestAsync(DnsDatagram request, IPEndPoint remoteEP)
+        {
+            if (!_enableBlocking)
+                return Task.FromResult<DnsDatagram>(null);
 
-                return null;
-            }
+            string groupName = GetGroupName(request, remoteEP);
+            if ((groupName is null) || !_groups.TryGetValue(groupName, out Group group) || !group.EnableBlocking)
+                return Task.FromResult<DnsDatagram>(null);
+
+            DnsQuestionRecord question = request.Question[0];
+
+            if (!group.IsZoneBlocked(question.Name, out string blockedDomain, out string blockedRegex, out Uri blockListUrl))
+                return Task.FromResult<DnsDatagram>(null);
 
             string GetBlockingReport()
             {
@@ -493,7 +530,7 @@ namespace AdvancedBlocking
 
                 DnsResourceRecord[] answer = new DnsResourceRecord[] { new DnsResourceRecord(question.Name, DnsResourceRecordType.TXT, question.Class, 60, new DnsTXTRecordData(blockingReport)) };
 
-                return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, false, false, false, DnsResponseCode.NoError, request.Question, answer) { Tag = DnsServerResponseType.Blocked };
+                return Task.FromResult(new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, false, false, false, DnsResponseCode.NoError, request.Question, answer));
             }
             else
             {
@@ -578,7 +615,7 @@ namespace AdvancedBlocking
                     }
                 }
 
-                return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, false, false, false, rcode, request.Question, answer, authority, null, request.EDNS is null ? ushort.MinValue : _dnsServer.UdpPayloadSize, EDnsHeaderFlags.None, options) { Tag = DnsServerResponseType.Blocked };
+                return Task.FromResult(new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, false, false, false, rcode, request.Question, answer, authority, null, request.EDNS is null ? ushort.MinValue : _dnsServer.UdpPayloadSize, EDnsHeaderFlags.None, options));
             }
         }
 
@@ -765,26 +802,22 @@ namespace AdvancedBlocking
                 }
             }
 
-            public bool IsZoneBlocked(string domain, out bool allowed, out string blockedDomain, out string blockedRegex, out Uri listUrl)
+            public bool IsZoneAllowed(string domain)
             {
                 domain = domain.ToLower();
 
                 //allowed, allow list zone, allowedRegex, regex allow list zone, adblock list zone
-                if (IsZoneFound(_allowed, domain, out _) || IsZoneFound(_allowListZones, domain, out _, out _) || IsMatchFound(_allowedRegex, domain, out _) || IsMatchFound(_regexAllowListZones, domain, out _, out _) || IsZoneAllowed(_adBlockListZones, domain, out _, out _))
-                {
-                    //found zone allowed
-                    allowed = true;
-                    blockedDomain = null;
-                    blockedRegex = null;
-                    listUrl = null;
-                    return false;
-                }
+                return IsZoneFound(_allowed, domain, out _) || IsZoneFound(_allowListZones, domain, out _, out _) || IsMatchFound(_allowedRegex, domain, out _) || IsMatchFound(_regexAllowListZones, domain, out _, out _) || App.IsZoneAllowed(_adBlockListZones, domain, out _, out _);
+            }
+
+            public bool IsZoneBlocked(string domain, out string blockedDomain, out string blockedRegex, out Uri listUrl)
+            {
+                domain = domain.ToLower();
 
                 //blocked
                 if (IsZoneFound(_blocked, domain, out string foundZone1))
                 {
                     //found zone blocked
-                    allowed = false;
                     blockedDomain = foundZone1;
                     blockedRegex = null;
                     listUrl = null;
@@ -795,7 +828,6 @@ namespace AdvancedBlocking
                 if (IsZoneFound(_blockListZones, domain, out string foundZone2, out Uri blockListUrl1))
                 {
                     //found zone blocked
-                    allowed = false;
                     blockedDomain = foundZone2;
                     blockedRegex = null;
                     listUrl = blockListUrl1;
@@ -806,7 +838,6 @@ namespace AdvancedBlocking
                 if (IsMatchFound(_blockedRegex, domain, out string blockedPattern1))
                 {
                     //found pattern blocked
-                    allowed = false;
                     blockedDomain = null;
                     blockedRegex = blockedPattern1;
                     listUrl = null;
@@ -817,7 +848,6 @@ namespace AdvancedBlocking
                 if (IsMatchFound(_regexBlockListZones, domain, out string blockedPattern2, out Uri blockListUrl2))
                 {
                     //found pattern blocked
-                    allowed = false;
                     blockedDomain = null;
                     blockedRegex = blockedPattern2;
                     listUrl = blockListUrl2;
@@ -828,14 +858,12 @@ namespace AdvancedBlocking
                 if (App.IsZoneBlocked(_adBlockListZones, domain, out string foundZone3, out Uri blockListUrl3))
                 {
                     //found zone blocked
-                    allowed = false;
                     blockedDomain = foundZone3;
                     blockedRegex = null;
                     listUrl = blockListUrl3;
                     return true;
                 }
 
-                allowed = false;
                 blockedDomain = null;
                 blockedRegex = null;
                 listUrl = null;