// 正引き v4/v6 Dual Stack 対応
public async Task <List <IPAddress> > GetIpAddressListDualStackAsync(string hostname, bool preferV6 = false, CancellationToken cancel = default, bool noCache = false)
{
try
{
ConcurrentBag <Tuple <IPAddress, int> > list = new();
var queryTypeList = new DnsResolverQueryType[] { DnsResolverQueryType.A, DnsResolverQueryType.AAAA };
await TaskUtil.ForEachAsync(int.MaxValue, queryTypeList, async (item, index, cancel) =>
{
var resultsList = await GetIpAddressListSingleStackAsync(hostname, item, null, cancel, noCache);
if (resultsList != null)
{
int i = 0;
foreach (var ip in resultsList.Distinct(IpComparer.Comparer))
{
list.Add(new Tuple <IPAddress, int>(ip, i));
i++;
}
}
}, cancel, 0);
return(list.OrderBy(x => (int)x.Item1.AddressFamily * (preferV6 ? -1 : 1)).Select(x => x.Item1).Distinct().ToList());
}
catch
{
return(new List <IPAddress>(0));
}
}
protected abstract Task <IEnumerable <IPAddress>?> GetIpAddressListImplAsync(string hostname, DnsResolverQueryType queryType, Ref <DnsAdditionalResults>?additional = null, CancellationToken cancel = default);
protected override async Task <IEnumerable <IPAddress>?> GetIpAddressListImplAsync(string hostname, DnsResolverQueryType queryType, Ref <DnsAdditionalResults>?additional = null, CancellationToken cancel = default)
{
DnsAdditionalResults additionalData = new DnsAdditionalResults(true, false);
QueryType qt;
switch (queryType)
{
case DnsResolverQueryType.A:
qt = QueryType.A;
break;
case DnsResolverQueryType.AAAA:
qt = QueryType.AAAA;
break;
default:
throw new ArgumentOutOfRangeException(nameof(queryType));
}
try
{
var res = await Client.QueryAsync(hostname, qt, queryClass : QueryClass.IN, cancel);
if (res.Header.ResponseCode == DnsHeaderResponseCode.NotExistentDomain)
{
additionalData = new DnsAdditionalResults(false, true);
}
if (res.HasError)
{
additionalData = new DnsAdditionalResults(true, false);
return(null);
}
if (qt == QueryType.A)
{
return(res.Answers?.ARecords().Where(x => x.Address.AddressFamily == AddressFamily.InterNetwork).Select(x => x.Address).ToArray() ?? null);
}
else
{
return(res.Answers?.AaaaRecords().Where(x => x.Address.AddressFamily == AddressFamily.InterNetworkV6).Select(x => x.Address).ToArray() ?? null);
}
}
finally
{
additional?.Set(additionalData);
}
}
