ZoneTree: Updated KeysMatch() to optionally support wildcard matching. Updated FindZoneNode() to optionally support wildcard search, added closestSubDomainNode out parameter, and fixed minor issue with wildcard. Code refactoring done.

2026-01-06 08:45:32 +00:00 · 2022-02-27 18:04:56 +05:30
parent d29e50a4e5
commit f5d25763be
1 changed files with 108 additions and 72 deletions
--- a/DnsServerCore/Dns/Trees/ZoneTree.cs
+++ b/DnsServerCore/Dns/Trees/ZoneTree.cs
@@ -18,7 +18,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

 using DnsServerCore.Dns.Zones;
-using System;
 using System.Collections.Generic;
 using System.Threading;

@@ -90,61 +89,78 @@ namespace DnsServerCore.Dns.Trees
            return key;
        }

-        private static bool KeysMatch(byte[] key1, byte[] key2)
+        private static bool KeysMatch(byte[] key1, byte[] key2, bool matchWildcard)
        {
-            //com.example.*.
-            //com.example.*.www.
-            //com.example.abc.www.
-
-            int i = 0;
-            int j = 0;
-
-            while ((i < key1.Length) && (j < key2.Length))
+            if (matchWildcard)
            {
-                if (key1[i] == 1) //[*]
+                //com.example.*.
+                //com.example.*.www.
+                //com.example.abc.www.
+
+                int i = 0;
+                int j = 0;
+
+                while ((i < key1.Length) && (j < key2.Length))
                {
-                    if (i == key1.Length - 2)
-                        return true;
-
-                    //skip j to next label
-                    while (j < key2.Length)
+                    if (key1[i] == 1) //[*]
                    {
-                        if (key2[j] == 0) //[.]
-                            break;
+                        if (i == key1.Length - 2)
+                            return true;

-                        j++;
-                    }
+                        //skip j to next label
+                        while (j < key2.Length)
+                        {
+                            if (key2[j] == 0) //[.]
+                                break;

-                    i++;
-                    continue;
-                }
-
-                if (key2[j] == 1) //[*]
-                {
-                    if (j == key2.Length - 2)
-                        return true;
-
-                    //skip i to next label
-                    while (i < key1.Length)
-                    {
-                        if (key1[i] == 0) //[.]
-                            break;
+                            j++;
+                        }

                        i++;
+                        continue;
                    }

+                    if (key2[j] == 1) //[*]
+                    {
+                        if (j == key2.Length - 2)
+                            return true;
+
+                        //skip i to next label
+                        while (i < key1.Length)
+                        {
+                            if (key1[i] == 0) //[.]
+                                break;
+
+                            i++;
+                        }
+
+                        j++;
+                        continue;
+                    }
+
+                    if (key1[i] != key2[j])
+                        return false;
+
+                    i++;
                    j++;
-                    continue;
                }

-                if (key1[i] != key2[j])
+                return (i == key1.Length) && (j == key2.Length);
+            }
+            else
+            {
+                //exact match
+                if (key1.Length != key2.Length)
                    return false;

-                i++;
-                j++;
-            }
+                for (int i = 0; i < key1.Length; i++)
+                {
+                    if (key1[i] != key2[i])
+                        return false;
+                }

-            return (i == key1.Length) && (j == key2.Length);
+                return true;
+            }
        }

        #endregion
@@ -190,34 +206,45 @@ namespace DnsServerCore.Dns.Trees
            return (i == mainKey.Length) && (j < testKey.Length);
        }

-        protected TNode FindZoneNode(byte[] key, out Node closestNode, out Node closestAuthorityNode, out TSubDomainZone closestSubDomain, out TSubDomainZone closestDelegation, out TApexZone closestAuthority)
+        protected TNode FindZoneNode(byte[] key, bool matchWildcard, out Node currentNode, out Node closestSubDomainNode, out Node closestAuthorityNode, out TSubDomainZone closestSubDomain, out TSubDomainZone closestDelegation, out TApexZone closestAuthority)
        {
-            closestNode = _root;
+            closestSubDomainNode = null;
            closestAuthorityNode = null;
            closestSubDomain = null;
            closestDelegation = null;
            closestAuthority = null;

+            currentNode = _root;
            Node wildcard = null;
            int i = 0;

            while (i <= key.Length)
            {
-                //find authority zone
-                NodeValue value = closestNode.Value;
-                if (value is not null)
+                //inspect the current node
+                NodeValue value = currentNode.Value;
+                if ((value is not null) && (value.Key.Length <= key.Length))
                {
-                    TNode zoneValue = value.Value;
-                    if ((zoneValue is not null) && IsKeySubDomain(value.Key, key))
+                    TNode zoneNode = value.Value;
+                    if ((zoneNode is not null) && IsKeySubDomain(value.Key, key))
                    {
+                        //find closest values
+                        TSubDomainZone subDomain = null;
                        TApexZone authority = null;

-                        GetClosestValuesForZone(zoneValue, ref closestSubDomain, ref closestDelegation, ref authority);
+                        GetClosestValuesForZone(zoneNode, ref subDomain, ref closestDelegation, ref authority);
+
+                        if (subDomain is not null)
+                        {
+                            closestSubDomain = subDomain;
+                            closestSubDomainNode = currentNode;
+                        }

                        if (authority is not null)
                        {
                            closestAuthority = authority;
-                            closestAuthorityNode = closestNode;
+                            closestAuthorityNode = currentNode;
+
+                            wildcard = null; //clear previous wildcard node from the previous authority
                        }
                    }
                }
@@ -225,13 +252,18 @@ namespace DnsServerCore.Dns.Trees
                if (i == key.Length)
                    break;

-                Node[] children = closestNode.Children;
+                Node[] children = currentNode.Children;
                if (children is null)
                    break;

-                Node child = Volatile.Read(ref children[1]); //[*]
-                if (child is not null)
-                    wildcard = child;
+                Node child;
+
+                if (matchWildcard)
+                {
+                    child = Volatile.Read(ref children[1]); //[*]
+                    if (child is not null)
+                        wildcard = child;
+                }

                child = Volatile.Read(ref children[key[i]]);
                if (child is null)
@@ -248,34 +280,41 @@ namespace DnsServerCore.Dns.Trees
                            break;
                    }

-                    closestNode = wildcard;
+                    currentNode = wildcard;
                    wildcard = null;
                    continue;
                }

-                closestNode = child;
+                currentNode = child;
                i++;
            }

            {
-                NodeValue value = closestNode.Value;
+                NodeValue value = currentNode.Value;
                if (value is not null)
                {
                    //match exact + wildcard keys
-                    if (KeysMatch(key, value.Key))
+                    if (KeysMatch(key, value.Key, matchWildcard))
                    {
-                        //update authority since the matched zone is apex zone
-                        TNode zoneValue = value.Value;
-                        if (zoneValue is not null)
+                        //find closest values since the matched zone may be apex zone
+                        TNode zoneNode = value.Value;
+                        if (zoneNode is not null)
                        {
+                            TSubDomainZone subDomain = null;
                            TApexZone authority = null;

-                            GetClosestValuesForZone(zoneValue, ref closestSubDomain, ref closestDelegation, ref authority);
+                            GetClosestValuesForZone(zoneNode, ref subDomain, ref closestDelegation, ref authority);
+
+                            if (subDomain is not null)
+                            {
+                                closestSubDomain = subDomain;
+                                closestSubDomainNode = currentNode;
+                            }

                            if (authority is not null)
                            {
                                closestAuthority = authority;
-                                closestAuthorityNode = closestNode;
+                                closestAuthorityNode = currentNode;
                            }
                        }

@@ -286,7 +325,7 @@ namespace DnsServerCore.Dns.Trees

            if (wildcard is not null)
            {
-                //wildcard node found
+                //inspect wildcard node value
                NodeValue value = wildcard.Value;
                if (value is null)
                {
@@ -301,7 +340,7 @@ namespace DnsServerCore.Dns.Trees
                            if (value is not null)
                            {
                                //match wildcard keys
-                                if (KeysMatch(key, value.Key))
+                                if (KeysMatch(key, value.Key, true))
                                    return value.Value; //found matching wildcard value
                            }
                        }
@@ -310,7 +349,7 @@ namespace DnsServerCore.Dns.Trees
                else
                {
                    //match wildcard keys
-                    if (KeysMatch(key, value.Key))
+                    if (KeysMatch(key, value.Key, true))
                        return value.Value; //found matching wildcard value
                }
            }
@@ -327,13 +366,10 @@ namespace DnsServerCore.Dns.Trees

        public void ListSubDomains(string domain, List<string> subDomains)
        {
-            if (domain is null)
-                throw new ArgumentNullException(nameof(domain));
-
            byte[] bKey = ConvertToByteKey(domain);

-            _ = _root.FindNodeValue(bKey, out Node closestNode);
-            Node current = closestNode;
+            _ = _root.FindNodeValue(bKey, out Node currentNode);
+            Node current = currentNode;
            NodeValue value;

            do
@@ -348,7 +384,7 @@ namespace DnsServerCore.Dns.Trees
                            subDomains.Add(label);
                    }
                }
-                else if ((current.K == 0) && (current.Depth > closestNode.Depth)) //[.]
+                else if ((current.K == 0) && (current.Depth > currentNode.Depth)) //[.]
                {
                    byte[] nodeKey = GetNodeKey(current);
                    if (IsKeySubDomain(bKey, nodeKey))
@@ -359,7 +395,7 @@ namespace DnsServerCore.Dns.Trees
                    }
                }

-                current = GetNextChildZoneNode(current, closestNode.Depth);
+                current = GetNextChildZoneNode(current, currentNode.Depth);
            }
            while (current is not null);
        }