public async Task <IReadOnlyList <NameServerAddress> > GetPrimaryNameServerAddressesAsync(DnsServer dnsServer)
{
DnsResourceRecord soaRecord = _entries[DnsResourceRecordType.SOA][0];
IReadOnlyList <NameServerAddress> primaryNameServers = soaRecord.GetPrimaryNameServers();
if (primaryNameServers.Count > 0)
{
List <NameServerAddress> resolvedNameServers = new List <NameServerAddress>(primaryNameServers.Count * 2);
foreach (NameServerAddress nameServer in primaryNameServers)
{
if (nameServer.IsIPEndPointStale)
{
await ResolveNameServerAddressesAsync(dnsServer, nameServer.Host, nameServer.Port, nameServer.Protocol, resolvedNameServers);
}
else
{
resolvedNameServers.Add(nameServer);
}
}
return(resolvedNameServers);
}
string primaryNameServer = (soaRecord.RDATA as DnsSOARecordData).PrimaryNameServer;
IReadOnlyList <DnsResourceRecord> nsRecords = GetRecords(DnsResourceRecordType.NS); //stub zone has no authority so cant use QueryRecords
List <NameServerAddress> nameServers = new List <NameServerAddress>(nsRecords.Count * 2);
foreach (DnsResourceRecord nsRecord in nsRecords)
{
if (nsRecord.IsDisabled())
{
continue;
}
if (primaryNameServer.Equals((nsRecord.RDATA as DnsNSRecordData).NameServer, StringComparison.OrdinalIgnoreCase))
{
//found primary NS
await ResolveNameServerAddressesAsync(dnsServer, nsRecord, nameServers);
break;
}
}
if (nameServers.Count < 1)
{
await ResolveNameServerAddressesAsync(dnsServer, primaryNameServer, 53, DnsTransportProtocol.Udp, nameServers);
}
return(nameServers);
}
