From 2dd9b89e745b244dda6c19f7aec5964c81e1fd12 Mon Sep 17 00:00:00 2001
From: Shreyas Zare <shreyas@technitium.com>
Date: Sat, 3 Apr 2021 12:32:23 +0530
Subject: [PATCH] AuthZoneManager: implemented QueryClosestDelegation().

---
 .../Dns/ZoneManagers/AuthZoneManager.cs          | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/DnsServerCore/Dns/ZoneManagers/AuthZoneManager.cs b/DnsServerCore/Dns/ZoneManagers/AuthZoneManager.cs
index fe224605..ca81c919 100644
--- a/DnsServerCore/Dns/ZoneManagers/AuthZoneManager.cs
+++ b/DnsServerCore/Dns/ZoneManagers/AuthZoneManager.cs
@@ -888,6 +888,22 @@ namespace DnsServerCore.Dns.ZoneManagers
             return _root.ListSubDomains(domain);
         }
 
+        public DnsDatagram QueryClosestDelegation(DnsDatagram request)
+        {
+            _ = _root.FindZone(request.Question[0].Name, out AuthZone delegation, out _, out _);
+            if (delegation == null)
+            {
+                //no delegation found
+                return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.Refused, request.Question);
+            }
+
+            //return closest name servers in delegation
+            IReadOnlyList<DnsResourceRecord> authority = delegation.QueryRecords(DnsResourceRecordType.NS);
+            IReadOnlyList<DnsResourceRecord> additional = GetAdditionalRecords(authority);
+
+            return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.NoError, request.Question, null, authority, additional);
+        }
+
         public DnsDatagram Query(DnsDatagram request, bool isRecursionAllowed)
         {
             AuthZone zone = _root.FindZone(request.Question[0].Name, out AuthZone delegation, out AuthZone authZone, out bool hasSubDomains);