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DnsServer: implemented Zone changes and new DnsClient. Code refactoring done.

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This commit is contained in:
Shreyas Zare
2017-09-30 15:53:00 +05:30
parent 067cb5adab
commit db9d1fa8af
1 changed files with 87 additions and 210 deletions
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297
DnsServerCore/DnsServer.cs
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@@ -1,5 +1,5 @@
/*
Technitium Library
Technitium DNS Server
Copyright (C) 2017 Shreyas Zare (shreyas@technitium.com)
This program is free software: you can redistribute it and/or modify
@@ -24,7 +24,7 @@ using System.Net;
using System.Net.Sockets;
using System.Threading;
using TechnitiumLibrary.IO;
using TechnitiumLibrary.Net;
using TechnitiumLibrary.Net.Dns;
namespace DnsServerCore
{
@@ -35,18 +35,20 @@ namespace DnsServerCore
const int TCP_SOCKET_SEND_TIMEOUT = 30000;
const int TCP_SOCKET_RECV_TIMEOUT = 60000;
Socket _udpListener;
Thread _udpListenerThread;
readonly Socket _udpListener;
readonly Thread _udpListenerThread;
Socket _tcpListener;
Thread _tcpListenerThread;
readonly Socket _tcpListener;
readonly Thread _tcpListenerThread;
Zone _authoritativeZoneRoot = new Zone(true);
Zone _cacheZoneRoot = new Zone(false);
readonly Zone _authoritativeZoneRoot = new Zone(true);
readonly Zone _cacheZoneRoot = new Zone(false);
bool _allowRecursion;
readonly IDnsCache _dnsCache;
bool _allowRecursion = false;
NameServerAddress[] _forwarders;
bool _enableIPv6 = false;
bool _preferIPv6 = false;
int _retries = 2;
#endregion
@@ -57,12 +59,14 @@ namespace DnsServerCore
: this(new IPEndPoint(IPAddress.IPv6Any, 53))
{ }
public DnsServer(IPAddress localIP, int port = 53)
: this(new IPEndPoint(localIP, port))
public DnsServer(IPAddress localIP)
: this(new IPEndPoint(localIP, 53))
{ }
public DnsServer(IPEndPoint localEP)
{
_dnsCache = new DnsCache(_cacheZoneRoot);
_udpListener = new Socket(AddressFamily.InterNetworkV6, SocketType.Dgram, ProtocolType.Udp);
_udpListener.SetSocketOption(SocketOptionLevel.IPv6, SocketOptionName.IPv6Only, false);
_udpListener.Bind(localEP);
@@ -75,11 +79,11 @@ namespace DnsServerCore
//start reading query packets
_udpListenerThread = new Thread(ReadUdpQueryPacketsAsync);
_udpListenerThread.IsBackground = true;
_udpListenerThread.Start(_udpListener);
_udpListenerThread.Start();
_tcpListenerThread = new Thread(AcceptTcpConnectionAsync);
_tcpListenerThread.IsBackground = true;
_tcpListenerThread.Start(_tcpListener);
_tcpListenerThread.Start();
}
#endregion
@@ -88,11 +92,6 @@ namespace DnsServerCore
bool _disposed = false;
~DnsServer()
{
Dispose(false);
}
public void Dispose()
{
Dispose(true);
@@ -122,21 +121,19 @@ namespace DnsServerCore
private void ReadUdpQueryPacketsAsync(object parameter)
{
Socket udpListener = parameter as Socket;
EndPoint remoteEP;
FixMemoryStream recvBufferStream = new FixMemoryStream(128);
FixMemoryStream sendBufferStream = new FixMemoryStream(512);
int bytesRecv;
if (udpListener.AddressFamily == AddressFamily.InterNetwork)
if (_udpListener.AddressFamily == AddressFamily.InterNetwork)
remoteEP = new IPEndPoint(IPAddress.Any, 0);
else
remoteEP = new IPEndPoint(IPAddress.IPv6Any, 0);
while (true)
{
bytesRecv = udpListener.ReceiveFrom(recvBufferStream.Buffer, ref remoteEP);
bytesRecv = _udpListener.ReceiveFrom(recvBufferStream.Buffer, ref remoteEP);
if (bytesRecv > 0)
{
@@ -167,7 +164,7 @@ namespace DnsServerCore
}
//send dns datagram
udpListener.SendTo(sendBufferStream.Buffer, 0, (int)sendBufferStream.Position, SocketFlags.None, remoteEP);
_udpListener.SendTo(sendBufferStream.Buffer, 0, (int)sendBufferStream.Position, SocketFlags.None, remoteEP);
}
}
catch
@@ -178,11 +175,9 @@ namespace DnsServerCore
private void AcceptTcpConnectionAsync(object parameter)
{
Socket tcpListener = parameter as Socket;
while (true)
{
Socket socket = tcpListener.Accept();
Socket socket = _tcpListener.Accept();
socket.NoDelay = true;
socket.SendTimeout = TCP_SOCKET_SEND_TIMEOUT;
@@ -285,14 +280,17 @@ namespace DnsServerCore
switch (request.Header.OPCODE)
{
case DnsOpcode.StandardQuery:
if (request.Question.Length != 1)
return new DnsDatagram(new DnsHeader(request.Header.Identifier, true, request.Header.OPCODE, false, false, request.Header.RecursionDesired, _allowRecursion, false, false, DnsResponseCode.Refused, request.Header.QDCOUNT, 0, 0, 0), request.Question, null, null, null);
try
{
DnsDatagram authoritativeResponse = Zone.Query(_authoritativeZoneRoot, request, _enableIPv6);
DnsDatagram authoritativeResponse = _authoritativeZoneRoot.Query(request);
if ((authoritativeResponse.Header.RCODE != DnsResponseCode.Refused) || !request.Header.RecursionDesired || !_allowRecursion)
if ((authoritativeResponse.Header.AuthoritativeAnswer) || !request.Header.RecursionDesired || !_allowRecursion)
return authoritativeResponse;
return RecursiveQuery(request);
return ProcessRecursiveQuery(request);
}
catch
{
@@ -304,171 +302,42 @@ namespace DnsServerCore
}
}
public DnsDatagram RecursiveQuery(DnsDatagram request)
public DnsDatagram ProcessRecursiveQuery(DnsDatagram request)
{
DnsDatagram originalRequest = request;
List<DnsDatagram> responses = new List<DnsDatagram>(1);
DnsDatagram response = DnsClient.ResolveViaNameServers(_forwarders, request.Question[0], _dnsCache, null, _preferIPv6, false, _retries);
while (true)
if ((response.Header.RCODE == DnsResponseCode.NoError) && (response.Answer.Length > 0))
{
DnsDatagram response = Resolve(request);
responses.Add(response);
if (response.Header.RCODE != DnsResponseCode.NoError)
break;
if (response.Answer.Length == 0)
break;
List<DnsQuestionRecord> newQuestions = new List<DnsQuestionRecord>();
foreach (DnsQuestionRecord question in request.Question)
if ((response.Answer[0].Type == DnsResourceRecordType.CNAME) && (request.Question[0].Type != DnsResourceRecordType.CNAME) && (request.Question[0].Type != DnsResourceRecordType.ANY))
{
for (int i = 0; i < response.Answer.Length; i++)
{
DnsResourceRecord answerRecord = response.Answer[i];
DnsResourceRecord cnameRR = response.Answer[0];
if ((answerRecord.Type == DnsResourceRecordType.CNAME) && question.Name.Equals(answerRecord.Name, StringComparison.CurrentCultureIgnoreCase))
{
string cnameDomain = (answerRecord.RDATA as DnsCNAMERecord).CNAMEDomainName;
bool containsAnswer = false;
for (int j = i + 1; j < response.Answer.Length; j++)
{
DnsResourceRecord answer = response.Answer[j];
if ((answer.Type == question.Type) && cnameDomain.Equals(answer.Name, StringComparison.CurrentCultureIgnoreCase))
{
containsAnswer = true;
break;
}
}
if (!containsAnswer)
newQuestions.Add(new DnsQuestionRecord((answerRecord.RDATA as DnsCNAMERecord).CNAMEDomainName, question.Type, question.Class));
break;
}
}
}
if (newQuestions.Count == 0)
break;
request = new DnsDatagram(new DnsHeader(0, false, DnsOpcode.StandardQuery, false, false, true, false, false, false, DnsResponseCode.NoError, Convert.ToUInt16(newQuestions.Count), 0, 0, 0), newQuestions.ToArray(), null, null, null);
}
return MergeResponseAnswers(originalRequest, responses);
}
private DnsDatagram Resolve(DnsDatagram request)
{
DnsDatagram cacheResponse = Zone.Query(_cacheZoneRoot, request, _enableIPv6);
if (cacheResponse.Header.RCODE != DnsResponseCode.Refused)
return cacheResponse;
List<DnsDatagram> responses = new List<DnsDatagram>();
foreach (DnsQuestionRecord questionRecord in request.Question)
{
NameServerAddress[] nameServers;
if (_forwarders == null)
{
nameServers = NameServerAddress.GetNameServersFromResponse(cacheResponse, _enableIPv6);
if (nameServers.Length == 0)
{
if (_enableIPv6)
nameServers = DnsClient.ROOT_NAME_SERVERS_IPv6;
else
nameServers = DnsClient.ROOT_NAME_SERVERS_IPv4;
}
}
else
{
nameServers = _forwarders;
}
int hopCount = 0;
bool working = true;
bool tcp = false;
while (working && ((hopCount++) < 64))
{
DnsClient client = new DnsClient(nameServers, _enableIPv6, tcp, _retries);
DnsDatagram response = client.Resolve(questionRecord);
if (response.Header.Truncation)
{
tcp = true;
continue;
}
Zone.CacheResponse(_cacheZoneRoot, response);
switch (response.Header.RCODE)
{
case DnsResponseCode.NoError:
if ((response.Answer.Length > 0) || (response.Authority.Length == 0))
{
responses.Add(response);
working = false;
}
else
{
nameServers = NameServerAddress.GetNameServersFromResponse(response, _enableIPv6);
if (nameServers.Length == 0)
{
responses.Add(response);
working = false;
}
}
break;
default:
responses.Add(response);
working = false;
break;
}
}
}
return MergeResponseAnswers(request, responses);
}
private DnsDatagram MergeResponseAnswers(DnsDatagram request, List<DnsDatagram> responses)
{
switch (responses.Count)
{
case 0:
return null;
case 1:
DnsDatagram responseReceived = responses[0];
if (responseReceived.Answer.Length == 0)
return new DnsDatagram(new DnsHeader(request.Header.Identifier, true, request.Header.OPCODE, false, false, true, true, false, false, responseReceived.Header.RCODE, request.Header.QDCOUNT, responseReceived.Header.ANCOUNT, responseReceived.Header.NSCOUNT, 0), request.Question, responseReceived.Answer, responseReceived.Authority, null);
else
return new DnsDatagram(new DnsHeader(request.Header.Identifier, true, request.Header.OPCODE, false, false, true, true, false, false, responseReceived.Header.RCODE, request.Header.QDCOUNT, responseReceived.Header.ANCOUNT, 0, 0), request.Question, responseReceived.Answer, null, null);
default:
List<DnsResourceRecord> responseAnswer = new List<DnsResourceRecord>();
List<DnsResourceRecord> responseAuthority = new List<DnsResourceRecord>();
responseAnswer.Add(cnameRR);
foreach (DnsDatagram response in responses)
while (true)
{
responseAnswer.AddRange(response.Answer);
DnsDatagram cnameResponse = DnsClient.ResolveViaNameServers(_forwarders, (cnameRR.RDATA as DnsCNAMERecord).CNAMEDomainName, request.Question[0].Type, _dnsCache, null, _preferIPv6, false, _retries);
if ((response.Answer.Length == 0) && (response.Authority != null))
responseAuthority.AddRange(response.Authority);
if (cnameResponse.Header.RCODE != DnsResponseCode.NoError)
break;
if (cnameResponse.Answer.Length == 0)
break;
responseAnswer.AddRange(cnameResponse.Answer);
if (cnameResponse.Answer[0].Type != DnsResourceRecordType.CNAME)
break;
cnameRR = cnameResponse.Answer[0];
}
return new DnsDatagram(new DnsHeader(request.Header.Identifier, true, request.Header.OPCODE, false, false, true, true, false, false, responses[0].Header.RCODE, request.Header.QDCOUNT, Convert.ToUInt16(responseAnswer.Count), Convert.ToUInt16(responseAuthority.Count), 0), request.Question, responseAnswer.ToArray(), responseAuthority.ToArray(), null);
return new DnsDatagram(new DnsHeader(request.Header.Identifier, true, DnsOpcode.StandardQuery, false, false, true, true, false, false, DnsResponseCode.NoError, 1, Convert.ToUInt16(responseAnswer.Count), 0, 0), request.Question, responseAnswer.ToArray(), new DnsResourceRecord[] { }, new DnsResourceRecord[] { });
}
}
return new DnsDatagram(new DnsHeader(request.Header.Identifier, true, DnsOpcode.StandardQuery, false, false, true, true, false, false, DnsResponseCode.NoError, 1, Convert.ToUInt16(response.Answer.Length), 0, 0), request.Question, response.Answer, new DnsResourceRecord[] { }, new DnsResourceRecord[] { });
}
#endregion
@@ -493,10 +362,10 @@ namespace DnsServerCore
set { _forwarders = value; }
}
public bool EnableIPv6
public bool PreferIPv6
{
get { return _enableIPv6; }
set { _enableIPv6 = value; }
get { return _preferIPv6; }
set { _preferIPv6 = value; }
}
public int Retries
@@ -506,29 +375,37 @@ namespace DnsServerCore
}
#endregion
class DnsCache : IDnsCache
{
#region variables
readonly Zone _cacheZoneRoot;
#endregion
#region constructor
public DnsCache(Zone cacheZoneRoot)
{
_cacheZoneRoot = cacheZoneRoot;
}
#endregion
#region public
public DnsDatagram Query(DnsDatagram request)
{
return _cacheZoneRoot.Query(request);
}
public void CacheResponse(DnsDatagram response)
{
_cacheZoneRoot.CacheResponse(response);
}
#endregion
}
}
public class DnsServerException : Exception
{
#region constructors
public DnsServerException()
: base()
{ }
public DnsServerException(string message)
: base(message)
{ }
public DnsServerException(string message, Exception innerException)
: base(message, innerException)
{ }
protected DnsServerException(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context)
: base(info, context)
{ }
#endregion
}
}