mirror of
https://github.com/fergalmoran/DnsServer.git
synced 2026-05-21 10:36:09 +00:00
DefaultRecords: added new app that allows configuring default records for local zones.
This commit is contained in:
Shreyas Zare
274
Apps/DefaultRecordsApp/App.cs
Normal file
274
Apps/DefaultRecordsApp/App.cs
Normal file
@@ -0,0 +1,274 @@
|
||||
/*
|
||||
Technitium DNS Server
|
||||
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
|
||||
the Free Software Foundation, either version 3 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
This program is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
GNU General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU General Public License
|
||||
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
|
||||
*/
|
||||
|
||||
using DnsServerCore.ApplicationCommon;
|
||||
using System;
|
||||
using System.Collections.Generic;
|
||||
using System.IO;
|
||||
using System.Net;
|
||||
using System.Text;
|
||||
using System.Text.Json;
|
||||
using System.Threading.Tasks;
|
||||
using TechnitiumLibrary;
|
||||
using TechnitiumLibrary.Net.Dns;
|
||||
using TechnitiumLibrary.Net.Dns.ResourceRecords;
|
||||
|
||||
namespace DefaultRecords
|
||||
{
|
||||
public class App : IDnsApplication, IDnsPostProcessor
|
||||
{
|
||||
#region variables
|
||||
|
||||
IDnsServer _dnsServer;
|
||||
|
||||
bool _enableDefaultRecords;
|
||||
uint _defaultTtl;
|
||||
IReadOnlyDictionary<string, string[]> _zoneSetMap;
|
||||
IReadOnlyDictionary<string, Set> _sets;
|
||||
|
||||
#endregion
|
||||
|
||||
#region IDisposable
|
||||
|
||||
public void Dispose()
|
||||
{
|
||||
//do nothing
|
||||
}
|
||||
|
||||
#endregion
|
||||
|
||||
#region private
|
||||
|
||||
private static string GetParentZone(string domain)
|
||||
{
|
||||
int i = domain.IndexOf('.');
|
||||
if (i > -1)
|
||||
return domain.Substring(i + 1);
|
||||
|
||||
//dont return root zone
|
||||
return null;
|
||||
}
|
||||
|
||||
private bool TryGetMappedSets(string domain, out string zone, out string[] setNames)
|
||||
{
|
||||
domain = domain.ToLowerInvariant();
|
||||
|
||||
string parent;
|
||||
|
||||
do
|
||||
{
|
||||
if (_zoneSetMap.TryGetValue(domain, out setNames))
|
||||
{
|
||||
zone = domain;
|
||||
return true;
|
||||
}
|
||||
|
||||
parent = GetParentZone(domain);
|
||||
if (parent is null)
|
||||
{
|
||||
if (_zoneSetMap.TryGetValue("*", out setNames))
|
||||
{
|
||||
zone = "*";
|
||||
return true;
|
||||
}
|
||||
|
||||
break;
|
||||
}
|
||||
|
||||
domain = "*." + parent;
|
||||
|
||||
if (_zoneSetMap.TryGetValue(domain, out setNames))
|
||||
{
|
||||
zone = domain;
|
||||
return true;
|
||||
}
|
||||
|
||||
domain = parent;
|
||||
}
|
||||
while (true);
|
||||
|
||||
zone = null;
|
||||
return false;
|
||||
}
|
||||
|
||||
#endregion
|
||||
|
||||
#region public
|
||||
|
||||
public Task InitializeAsync(IDnsServer dnsServer, string config)
|
||||
{
|
||||
_dnsServer = dnsServer;
|
||||
|
||||
using JsonDocument jsonDocument = JsonDocument.Parse(config);
|
||||
JsonElement jsonConfig = jsonDocument.RootElement;
|
||||
|
||||
_enableDefaultRecords = jsonConfig.GetProperty("enableDefaultRecords").GetBoolean();
|
||||
_defaultTtl = jsonConfig.GetPropertyValue("defaultTtl", 3600u);
|
||||
|
||||
_zoneSetMap = jsonConfig.ReadObjectAsMap("zoneSetMap", delegate (string zone, JsonElement jsonSets)
|
||||
{
|
||||
string[] sets = jsonSets.GetArray();
|
||||
|
||||
return new Tuple<string, string[]>(zone.ToLowerInvariant(), sets);
|
||||
});
|
||||
|
||||
_sets = jsonConfig.ReadArrayAsMap("sets", delegate (JsonElement jsonSet)
|
||||
{
|
||||
Set set = new Set(jsonSet);
|
||||
|
||||
return new Tuple<string, Set>(set.Name, set);
|
||||
});
|
||||
|
||||
return Task.CompletedTask;
|
||||
}
|
||||
|
||||
public async Task<DnsDatagram> PostProcessAsync(DnsDatagram request, IPEndPoint remoteEP, DnsTransportProtocol protocol, DnsDatagram response)
|
||||
{
|
||||
if (!_enableDefaultRecords)
|
||||
return response;
|
||||
|
||||
if (!response.AuthoritativeAnswer || (response.OPCODE != DnsOpcode.StandardQuery))
|
||||
return response;
|
||||
|
||||
switch (response.RCODE)
|
||||
{
|
||||
case DnsResponseCode.NoError:
|
||||
case DnsResponseCode.NxDomain:
|
||||
break;
|
||||
|
||||
default:
|
||||
return response;
|
||||
}
|
||||
|
||||
DnsQuestionRecord question = request.Question[0];
|
||||
|
||||
if (!TryGetMappedSets(question.Name, out string zone, out string[] setNames))
|
||||
return response;
|
||||
|
||||
if (zone.StartsWith('*'))
|
||||
{
|
||||
DnsDatagram soaResponse = await _dnsServer.DirectQueryAsync(new DnsQuestionRecord(question.Name, DnsResourceRecordType.SOA, DnsClass.IN));
|
||||
if (soaResponse is null)
|
||||
return response;
|
||||
|
||||
if ((soaResponse.Answer.Count > 0) && (soaResponse.Answer[soaResponse.Answer.Count - 1].Type == DnsResourceRecordType.SOA))
|
||||
zone = soaResponse.Answer[soaResponse.Answer.Count - 1].Name;
|
||||
else if ((soaResponse.Authority.Count > 0) && (soaResponse.Authority[0].Type == DnsResourceRecordType.SOA))
|
||||
zone = soaResponse.Authority[0].Name;
|
||||
else
|
||||
return response;
|
||||
}
|
||||
|
||||
StringBuilder sb = new StringBuilder();
|
||||
|
||||
foreach (string setName in setNames)
|
||||
{
|
||||
if (_sets.TryGetValue(setName, out Set set) && set.Enable)
|
||||
{
|
||||
foreach (string record in set.Records)
|
||||
sb.AppendLine(record);
|
||||
}
|
||||
}
|
||||
|
||||
if (sb.Length == 0)
|
||||
return response;
|
||||
|
||||
StringReader sR = new StringReader(sb.ToString());
|
||||
IReadOnlyCollection<DnsResourceRecord> records = ZoneFile.ReadZoneFileFromAsync(sR, zone, _defaultTtl).Sync();
|
||||
|
||||
List<DnsResourceRecord> newAnswer = new List<DnsResourceRecord>(response.Answer.Count + records.Count);
|
||||
string qname = question.Name;
|
||||
|
||||
if (response.Answer.Count > 0)
|
||||
{
|
||||
newAnswer.AddRange(response.Answer);
|
||||
|
||||
DnsResourceRecord lastRR = response.Answer[response.Answer.Count - 1];
|
||||
if (lastRR.Type == DnsResourceRecordType.CNAME)
|
||||
qname = (lastRR.RDATA as DnsCNAMERecordData).Domain;
|
||||
}
|
||||
|
||||
foreach (DnsResourceRecord record in records)
|
||||
{
|
||||
if (record.Class != question.Class)
|
||||
continue;
|
||||
|
||||
if ((record.Type != question.Type) && (record.Type != DnsResourceRecordType.CNAME))
|
||||
continue;
|
||||
|
||||
if (!record.Name.Equals(qname, StringComparison.OrdinalIgnoreCase))
|
||||
continue;
|
||||
|
||||
newAnswer.Add(record);
|
||||
|
||||
if (record.Type == DnsResourceRecordType.CNAME)
|
||||
qname = (record.RDATA as DnsCNAMERecordData).Domain;
|
||||
}
|
||||
|
||||
if (newAnswer.Count == response.Answer.Count)
|
||||
return response;
|
||||
|
||||
return new DnsDatagram(response.Identifier, true, response.OPCODE, response.AuthoritativeAnswer, response.Truncation, response.RecursionDesired, response.RecursionAvailable, response.AuthenticData, response.CheckingDisabled, DnsResponseCode.NoError, response.Question, newAnswer) { Tag = response.Tag };
|
||||
}
|
||||
|
||||
#endregion
|
||||
|
||||
#region properties
|
||||
|
||||
public string Description
|
||||
{ get { return "Enables default records for configured local zones."; } }
|
||||
|
||||
#endregion
|
||||
|
||||
class Set
|
||||
{
|
||||
#region variables
|
||||
|
||||
readonly string _name;
|
||||
readonly bool _enable;
|
||||
readonly IReadOnlyCollection<string> _records;
|
||||
|
||||
#endregion
|
||||
|
||||
#region constructor
|
||||
|
||||
public Set(JsonElement jsonSet)
|
||||
{
|
||||
_name = jsonSet.GetProperty("name").GetString();
|
||||
_enable = jsonSet.GetProperty("enable").GetBoolean();
|
||||
_records = jsonSet.ReadArray("records");
|
||||
}
|
||||
|
||||
#endregion
|
||||
|
||||
#region properties
|
||||
|
||||
public string Name
|
||||
{ get { return _name; } }
|
||||
|
||||
public bool Enable
|
||||
{ get { return _enable; } }
|
||||
|
||||
public IReadOnlyCollection<string> Records
|
||||
{ get { return _records; } }
|
||||
|
||||
#endregion
|
||||
}
|
||||
}
|
||||
}
|
||||
27
Apps/DefaultRecordsApp/dnsApp.config
Normal file
27
Apps/DefaultRecordsApp/dnsApp.config
Normal file
@@ -0,0 +1,27 @@
|
||||
{
|
||||
"enableDefaultRecords": false,
|
||||
"defaultTtl": 3600,
|
||||
"zoneSetMap": {
|
||||
"*": ["set1"],
|
||||
"*.net": ["set2"],
|
||||
"example.org": ["set1", "set2"]
|
||||
},
|
||||
"sets": [
|
||||
{
|
||||
"name": "set1",
|
||||
"enable": true,
|
||||
"records": [
|
||||
"@ 3600 IN MX 10 mail.example.com.",
|
||||
"@ 3600 IN TXT \"v=spf1 a mx -all\""
|
||||
]
|
||||
},
|
||||
{
|
||||
"name": "set2",
|
||||
"enable": true,
|
||||
"records": [
|
||||
"www 3600 IN CNAME @",
|
||||
"@ 3600 IN A 1.2.3.4"
|
||||
]
|
||||
}
|
||||
]
|
||||
}
|
||||
Reference in New Issue
Block a user