private static Task ResolveNameServerAddressesAsync(DnsServer dnsServer, DnsResourceRecord nsRecord, List <NameServerAddress> outNameServers)
{
string nsDomain = (nsRecord.RDATA as DnsNSRecordData).NameServer;
IReadOnlyList <DnsResourceRecord> glueRecords = nsRecord.GetGlueRecords();
if (glueRecords.Count > 0)
{
foreach (DnsResourceRecord glueRecord in glueRecords)
{
switch (glueRecord.Type)
{
case DnsResourceRecordType.A:
outNameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsARecordData).Address));
break;
case DnsResourceRecordType.AAAA:
if (dnsServer.PreferIPv6)
{
outNameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsAAAARecordData).Address));
}
break;
}
}
return(Task.CompletedTask);
}
else
{
return(ResolveNameServerAddressesAsync(dnsServer, nsDomain, 53, DnsTransportProtocol.Udp, outNameServers));
}
}
private void ResolveAdditionalRecords(DnsResourceRecord refRecord, string domain, bool serveStale, bool dnssecOk, List <DnsResourceRecord> additionalRecords)
{
IReadOnlyList <DnsResourceRecord> glueRecords = refRecord.GetGlueRecords();
if (glueRecords.Count > 0)
{
bool added = false;
foreach (DnsResourceRecord glueRecord in glueRecords)
{
if (!glueRecord.IsStale)
{
added = true;
additionalRecords.Add(glueRecord);
if (dnssecOk)
{
IReadOnlyList <DnsResourceRecord> rrsigRecords = glueRecord.GetRecordInfo().RRSIGRecords;
if (rrsigRecords is not null)
{
additionalRecords.AddRange(rrsigRecords);
}
}
}
}
if (added)
{
return;
}
}
if (_root.TryGet(domain, out CacheZone cacheZone))
{
{
IReadOnlyList <DnsResourceRecord> records = cacheZone.QueryRecords(DnsResourceRecordType.A, serveStale, true);
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].Type == DnsResourceRecordType.AAAA))
{
additionalRecords.AddRange(records);
}
}
}
}
private void ResolveAdditionalRecords(DnsResourceRecord refRecord, string domain, bool serveStale, List <DnsResourceRecord> additionalRecords)
{
IReadOnlyList <DnsResourceRecord> glueRecords = refRecord.GetGlueRecords();
if (glueRecords.Count > 0)
{
bool added = false;
foreach (DnsResourceRecord glueRecord in glueRecords)
{
if (!glueRecord.IsStale)
{
added = true;
additionalRecords.Add(glueRecord);
}
}
if (added)
{
return;
}
}
CacheZone cacheZone = _root.FindZone(domain, out _, out _, out _);
if (cacheZone != null)
{
{
IReadOnlyList <DnsResourceRecord> records = cacheZone.QueryRecords(DnsResourceRecordType.A, serveStale, true);
if ((records.Count > 0) && (records[0].RDATA is DnsARecord))
{
additionalRecords.AddRange(records);
}
}
{
IReadOnlyList <DnsResourceRecord> records = cacheZone.QueryRecords(DnsResourceRecordType.AAAA, serveStale, true);
if ((records.Count > 0) && (records[0].RDATA is DnsAAAARecord))
{
additionalRecords.AddRange(records);
}
}
}
}
private static async Task <IReadOnlyList <NameServerAddress> > GetNameServerAddressesAsync(DnsServer dnsServer, DnsResourceRecord record)
{
string nsDomain;
switch (record.Type)
{
case DnsResourceRecordType.NS:
nsDomain = (record.RDATA as DnsNSRecord).NameServer;
break;
case DnsResourceRecordType.SOA:
nsDomain = (record.RDATA as DnsSOARecord).PrimaryNameServer;
break;
default:
throw new InvalidOperationException();
}
List <NameServerAddress> nameServers = new List <NameServerAddress>(2);
IReadOnlyList <DnsResourceRecord> glueRecords = record.GetGlueRecords();
if (glueRecords.Count > 0)
{
foreach (DnsResourceRecord glueRecord in glueRecords)
{
switch (glueRecord.Type)
{
case DnsResourceRecordType.A:
nameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsARecord).Address));
break;
case DnsResourceRecordType.AAAA:
if (dnsServer.PreferIPv6)
{
nameServers.Add(new NameServerAddress(nsDomain, (glueRecord.RDATA as DnsAAAARecord).Address));
}
break;
}
}
}
else
{
//resolve addresses
try
{
DnsDatagram response = await dnsServer.DirectQueryAsync(new DnsQuestionRecord(nsDomain, DnsResourceRecordType.A, DnsClass.IN));
if ((response != null) && (response.Answer.Count > 0))
{
IReadOnlyList <IPAddress> addresses = DnsClient.ParseResponseA(response);
foreach (IPAddress address in addresses)
{
nameServers.Add(new NameServerAddress(nsDomain, address));
}
}
}
catch
{ }
if (dnsServer.PreferIPv6)
{
try
{
DnsDatagram response = await dnsServer.DirectQueryAsync(new DnsQuestionRecord(nsDomain, DnsResourceRecordType.AAAA, DnsClass.IN));
if ((response != null) && (response.Answer.Count > 0))
{
IReadOnlyList <IPAddress> addresses = DnsClient.ParseResponseAAAA(response);
foreach (IPAddress address in addresses)
{
nameServers.Add(new NameServerAddress(nsDomain, address));
}
}
}
catch
{ }
}
}
return(nameServers);
}
