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CacheZoneManager: implemented ResolveCNAME() method to resolve CNAME from cache in one go for optimization. Updated ResolveAdditionalRecords() to use direct TryGet() method which costs less. Fixed issue with code condition check sequence when returning delegation NS records in QueryClosestDelegation() and Query() methods.

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This commit is contained in:
Shreyas Zare
2021-04-17 14:16:52 +05:30
parent 53873094ff
commit 5d1b8ba887
1 changed files with 82 additions and 37 deletions
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119
DnsServerCore/Dns/ZoneManagers/CacheZoneManager.cs
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@@ -100,6 +100,29 @@ namespace DnsServerCore.Dns.ZoneManagers
#region private
private void ResolveCNAME(DnsQuestionRecord question, DnsResourceRecord lastCNAME, bool serveStale, List<DnsResourceRecord> answerRecords)
{
int queryCount = 0;
do
{
if (!_root.TryGet((lastCNAME.RDATA as DnsCNAMERecord).Domain, out CacheZone cacheZone))
break;
IReadOnlyList<DnsResourceRecord> records = cacheZone.QueryRecords(question.Type, serveStale, true);
if (records.Count < 1)
break;
answerRecords.AddRange(records);
if (records[0].Type != DnsResourceRecordType.CNAME)
break;
lastCNAME = records[0];
}
while (++queryCount < DnsServer.MAX_CNAME_HOPS);
}
private IReadOnlyList<DnsResourceRecord> GetAdditionalRecords(IReadOnlyList<DnsResourceRecord> refRecords, bool serveStale)
{
List<DnsResourceRecord> additionalRecords = new List<DnsResourceRecord>();
@@ -154,18 +177,17 @@ namespace DnsServerCore.Dns.ZoneManagers
return;
}
CacheZone cacheZone = _root.FindZone(domain, out _, out _, out _);
if (cacheZone != null)
if (_root.TryGet(domain, out CacheZone cacheZone))
{
{
IReadOnlyList<DnsResourceRecord> records = cacheZone.QueryRecords(DnsResourceRecordType.A, serveStale, true);
if ((records.Count > 0) && (records[0].RDATA is DnsARecord))
if ((records.Count > 0) && (records[0].Type == DnsResourceRecordType.A))
additionalRecords.AddRange(records);
}
{
IReadOnlyList<DnsResourceRecord> records = cacheZone.QueryRecords(DnsResourceRecordType.AAAA, serveStale, true);
if ((records.Count > 0) && (records[0].RDATA is DnsAAAARecord))
if ((records.Count > 0) && (records[0].Type == DnsResourceRecordType.AAAA))
additionalRecords.AddRange(records);
}
}
@@ -214,69 +236,89 @@ namespace DnsServerCore.Dns.ZoneManagers
public DnsDatagram QueryClosestDelegation(DnsDatagram request)
{
_ = _root.FindZone(request.Question[0].Name, out CacheZone delegation, out _, out _);
if (delegation == null)
if (delegation != null)
{
//no cached 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> closestAuthority = delegation.QueryRecords(DnsResourceRecordType.NS, false, true);
if ((closestAuthority.Count > 0) && (closestAuthority[0].Type == DnsResourceRecordType.NS))
{
IReadOnlyList<DnsResourceRecord> additional = GetAdditionalRecords(closestAuthority, false);
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.NoError, request.Question, null, closestAuthority, additional);
}
}
//return closest name servers in delegation
IReadOnlyList<DnsResourceRecord> authority = delegation.QueryRecords(DnsResourceRecordType.NS, false, true);
IReadOnlyList<DnsResourceRecord> additional = GetAdditionalRecords(authority, false);
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.NoError, request.Question, null, authority, additional);
//no cached delegation found
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.Refused, request.Question);
}
public override DnsDatagram Query(DnsDatagram request, bool serveStale = false)
{
CacheZone zone = _root.FindZone(request.Question[0].Name, out CacheZone delegation, out _, out _);
DnsQuestionRecord question = request.Question[0];
CacheZone zone = _root.FindZone(question.Name, out CacheZone delegation, out _, out _);
if (zone == null)
{
//zone not found
if (delegation == null)
if (delegation != null)
{
//no cached 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> closestAuthority = delegation.QueryRecords(DnsResourceRecordType.NS, serveStale, true);
if ((closestAuthority.Count > 0) && (closestAuthority[0].Type == DnsResourceRecordType.NS))
{
IReadOnlyList<DnsResourceRecord> additional = GetAdditionalRecords(closestAuthority, serveStale);
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.NoError, request.Question, null, closestAuthority, additional);
}
}
//return closest name servers in delegation
IReadOnlyList<DnsResourceRecord> authority = delegation.QueryRecords(DnsResourceRecordType.NS, serveStale, true);
IReadOnlyList<DnsResourceRecord> additional = GetAdditionalRecords(authority, serveStale);
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.NoError, request.Question, null, authority, additional);
//no cached delegation found
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.Refused, request.Question);
}
//zone found
IReadOnlyList<DnsResourceRecord> answers = zone.QueryRecords(request.Question[0].Type, serveStale, false);
IReadOnlyList<DnsResourceRecord> answers = zone.QueryRecords(question.Type, serveStale, false);
if (answers.Count > 0)
{
//answer found in cache
if (answers[0].RDATA is DnsEmptyRecord)
DnsResourceRecord firstRR = answers[0];
if (firstRR.RDATA is DnsEmptyRecord)
{
DnsResourceRecord[] authority = null;
DnsResourceRecord soaRecord = (answers[0].RDATA as DnsEmptyRecord).Authority;
DnsResourceRecord soaRecord = (firstRR.RDATA as DnsEmptyRecord).Authority;
if (soaRecord != null)
authority = new DnsResourceRecord[] { soaRecord };
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.NoError, request.Question, null, authority);
}
if (answers[0].RDATA is DnsNXRecord)
if (firstRR.RDATA is DnsNXRecord)
{
DnsResourceRecord[] authority = null;
DnsResourceRecord soaRecord = (answers[0].RDATA as DnsNXRecord).Authority;
DnsResourceRecord soaRecord = (firstRR.RDATA as DnsNXRecord).Authority;
if (soaRecord != null)
authority = new DnsResourceRecord[] { soaRecord };
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.NxDomain, request.Question, null, authority);
}
if (answers[0].RDATA is DnsFailureRecord)
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, (answers[0].RDATA as DnsFailureRecord).RCODE, request.Question);
if (firstRR.RDATA is DnsFailureRecord)
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, (firstRR.RDATA as DnsFailureRecord).RCODE, request.Question);
DnsResourceRecord lastRR = answers[answers.Count - 1];
if ((lastRR.Type != question.Type) && (lastRR.Type == DnsResourceRecordType.CNAME) && (question.Type != DnsResourceRecordType.ANY))
{
List<DnsResourceRecord> newAnswers = new List<DnsResourceRecord>(answers);
ResolveCNAME(question, lastRR, serveStale, newAnswers);
answers = newAnswers;
}
IReadOnlyList<DnsResourceRecord> additional = null;
switch (request.Question[0].Type)
switch (question.Type)
{
case DnsResourceRecordType.NS:
case DnsResourceRecordType.MX:
@@ -290,17 +332,20 @@ namespace DnsServerCore.Dns.ZoneManagers
else
{
//no answer in cache; check for closest delegation if any
if (delegation == null)
if (delegation != null)
{
//no cached 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> closestAuthority = delegation.QueryRecords(DnsResourceRecordType.NS, false, true);
if ((closestAuthority.Count > 0) && (closestAuthority[0].Type == DnsResourceRecordType.NS))
{
IReadOnlyList<DnsResourceRecord> additional = GetAdditionalRecords(closestAuthority, false);
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.NoError, request.Question, null, closestAuthority, additional);
}
}
//return closest name servers in delegation
IReadOnlyList<DnsResourceRecord> authority = delegation.QueryRecords(DnsResourceRecordType.NS, false, true);
IReadOnlyList<DnsResourceRecord> additional = GetAdditionalRecords(authority, false);
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.NoError, request.Question, null, authority, additional);
//no cached delegation found
return new DnsDatagram(request.Identifier, true, DnsOpcode.StandardQuery, false, false, request.RecursionDesired, true, false, false, DnsResponseCode.Refused, request.Question);
}
}