From 7f2e2c27209c77fbf683ba176b6113e30d74c31d Mon Sep 17 00:00:00 2001 From: Shreyas Zare Date: Sun, 5 Feb 2023 16:22:12 +0530 Subject: [PATCH] WildIpApp: updated app to respond with NODATA when no address was parsed to avoid NXDOMAIN response by the dns server. --- Apps/WildIpApp/App.cs | 44 ++++++++++++++++++++++++------------------- 1 file changed, 25 insertions(+), 19 deletions(-) diff --git a/Apps/WildIpApp/App.cs b/Apps/WildIpApp/App.cs index 274a22bc..2c637fd4 100644 --- a/Apps/WildIpApp/App.cs +++ b/Apps/WildIpApp/App.cs @@ -1,6 +1,6 @@ /* Technitium DNS Server -Copyright (C) 2022 Shreyas Zare (shreyas@technitium.com) +Copyright (C) 2023 Shreyas Zare (shreyas@technitium.com) This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -28,6 +28,12 @@ namespace WildIp { public class App : IDnsApplication, IDnsAppRecordRequestHandler { + #region variables + + IDnsServer _dnsServer; + + #endregion + #region IDisposable public void Dispose() @@ -41,18 +47,19 @@ namespace WildIp public Task InitializeAsync(IDnsServer dnsServer, string config) { - //do nothing + _dnsServer = dnsServer; + return Task.CompletedTask; } - public Task ProcessRequestAsync(DnsDatagram request, IPEndPoint remoteEP, DnsTransportProtocol protocol, bool isRecursionAllowed, string zoneName, string appRecordName, uint appRecordTtl, string appRecordData) + public async Task ProcessRequestAsync(DnsDatagram request, IPEndPoint remoteEP, DnsTransportProtocol protocol, bool isRecursionAllowed, string zoneName, string appRecordName, uint appRecordTtl, string appRecordData) { string qname = request.Question[0].Name; if (qname.Length == appRecordName.Length) - return Task.FromResult(null); + return null; - DnsResourceRecord answer; + DnsResourceRecord answer = null; switch (request.Question[0].Type) { @@ -69,12 +76,8 @@ namespace WildIp rawIp[i++] = x; } - if (i < 4) - return Task.FromResult(null); - - IPAddress address = new IPAddress(rawIp); - - answer = new DnsResourceRecord(request.Question[0].Name, DnsResourceRecordType.A, DnsClass.IN, appRecordTtl, new DnsARecordData(address)); + if (i == 4) + answer = new DnsResourceRecord(request.Question[0].Name, DnsResourceRecordType.A, DnsClass.IN, appRecordTtl, new DnsARecordData(new IPAddress(rawIp))); } break; @@ -90,18 +93,21 @@ namespace WildIp break; } - if (address is null) - return Task.FromResult(null); - - answer = new DnsResourceRecord(request.Question[0].Name, DnsResourceRecordType.AAAA, DnsClass.IN, appRecordTtl, new DnsAAAARecordData(address)); + if (address is not null) + answer = new DnsResourceRecord(request.Question[0].Name, DnsResourceRecordType.AAAA, DnsClass.IN, appRecordTtl, new DnsAAAARecordData(address)); } break; - - default: - return Task.FromResult(null); } - return Task.FromResult(new DnsDatagram(request.Identifier, true, request.OPCODE, true, false, request.RecursionDesired, isRecursionAllowed, false, false, DnsResponseCode.NoError, request.Question, new DnsResourceRecord[] { answer })); + if (answer is null) + { + //NODATA reponse + DnsDatagram soaResponse = await _dnsServer.DirectQueryAsync(new DnsQuestionRecord(zoneName, DnsResourceRecordType.SOA, DnsClass.IN)); + + return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, true, false, request.RecursionDesired, isRecursionAllowed, false, false, DnsResponseCode.NoError, request.Question, null, soaResponse.Answer); + } + + return new DnsDatagram(request.Identifier, true, request.OPCODE, true, false, request.RecursionDesired, isRecursionAllowed, false, false, DnsResponseCode.NoError, request.Question, new DnsResourceRecord[] { answer }); } #endregion