public async Task Cache_EntriesLowestTT_Expires()
{
var cache = new ResponseCache(true);
var record = new EmptyRecord(new ResourceRecordInfo("a", ResourceRecordType.A, QueryClass.IN, 1000, 100));
var recordB = new EmptyRecord(new ResourceRecordInfo("a", ResourceRecordType.A, QueryClass.IN, 100, 100));
var recordC = new EmptyRecord(new ResourceRecordInfo("a", ResourceRecordType.A, QueryClass.IN, 1, 100));
var response = new DnsResponseMessage(new DnsResponseHeader(1, 256, 1, 1, 0, 0), 0);
response.AddAnswer(record);
response.AddAdditional(recordB);
response.AddAuthority(recordC);
cache.Add("key", response.AsQueryResponse(new NameServer(IPAddress.Any), null));
await Task.Delay(200);
var item = cache.Get("key", out double?effectiveTtl);
Assert.NotNull(item);
Assert.Equal(1 * 1000, effectiveTtl);
await Task.Delay(1100);
var item3 = cache.Get("key", out double?effectiveTtl2);
Assert.Null(item3);
}
public async Task Cache_EntriesLowestTT_Expires()
{
var cache = new ResponseCache();
var record = new EmptyRecord(new ResourceRecord(DnsString.Parse("a"), ARecord.ResourceRecordType, QueryClass.In, 1000, 100));
var recordB = new EmptyRecord(new ResourceRecord(DnsString.Parse("a"), ARecord.ResourceRecordType, QueryClass.In, 100, 100));
var recordC = new EmptyRecord(new ResourceRecord(DnsString.Parse("a"), ARecord.ResourceRecordType, QueryClass.In, 1, 100));
var response = new DnsResponseMessage(new DnsResponseHeader(1, 256, 1, 1, 0, 0), 0)
{
Audit = new LookupClientAudit()
};
response.AddAnswer(record);
response.AddAdditional(recordB);
response.AddAuthority(recordC);
cache.Add("key", response.AsQueryResponse(new NameServer(IPAddress.Any)));
await Task.Delay(200);
var item = cache.Get("key", out var effectiveTtl);
Assert.NotNull(item);
Assert.Equal(1 * 1000, effectiveTtl);
await Task.Delay(1100);
var item3 = cache.Get("key", out _);
Assert.Null(item3);
}
/// <summary> Constructs the response object based upon the data received from the DNS server. </summary>
/// <param name="responseData">The data (byte[]) from the DNS server.</param>
/// <returns>Response message object.</returns>
public DnsResponseMessage ProcessResponse(ArraySegment <byte> responseData)
{
IDnsRecordFactory factory = new DnsRecordFactory(reader);
/*
* From index 0 till 11 bytes in the responseData array, we have the header items.
*/
ushort id = reader.ReadUInt16NetworkOrder(responseData);
ushort flags = reader.ReadUInt16NetworkOrder(responseData);
ushort questionCount = reader.ReadUInt16NetworkOrder(responseData);
ushort answerCount = reader.ReadUInt16NetworkOrder(responseData);
ushort nameServerCount = reader.ReadUInt16NetworkOrder(responseData);
ushort additionalCount = reader.ReadUInt16NetworkOrder(responseData);
/*
* We have got above data, now build the response header.
*/
DnsResponseHeader header = new DnsResponseHeader(id, flags, questionCount, answerCount, additionalCount, nameServerCount);
DnsResponseMessage response = new DnsResponseMessage(header, responseData.Count);
/*
* Next item in the response data is question that we sent to the DNS server which the server has copied onto the response message.
*/
for (int questionIndex = 0; questionIndex < questionCount; questionIndex++)
{
IDnsString questionString = reader.ReadQuestionQueryString(responseData);
DnsQuestion question = new DnsQuestion(questionString, (QueryType)reader.ReadUInt16NetworkOrder(responseData), (QueryClass)reader.ReadUInt16NetworkOrder(responseData));
response.AddQuestion(question);
}
for (int answerIndex = 0; answerIndex < answerCount; answerIndex++)
{
BaseResourceRecordInfo info = factory.ReadRecordInfo(responseData);
DnsResourceRecord record = factory.GetRecord(info, responseData);
response.AddAnswer(record);
}
for (int serverIndex = 0; serverIndex < nameServerCount; serverIndex++)
{
BaseResourceRecordInfo info = factory.ReadRecordInfo(responseData);
DnsResourceRecord record = factory.GetRecord(info, responseData);
response.AddAuthority(record);
}
for (int additionalIndex = 0; additionalIndex < additionalCount; additionalIndex++)
{
BaseResourceRecordInfo info = factory.ReadRecordInfo(responseData);
DnsResourceRecord record = factory.GetRecord(info, responseData);
response.AddAdditional(record);
}
return(response);
}
public async Task ResolveService_WithCnameRef()
{
var ns = new NameServer(IPAddress.Loopback, 8600);
var serviceName = "myservice";
var baseName = "service.consul";
var fullQuery = $"{serviceName}.{baseName}";
ushort prio = 99;
ushort weight = 69;
ushort port = 88;
var response = new DnsResponseMessage(new DnsResponseHeader(1234, (int)DnsResponseCode.NoError, 0, 0, 0, 0), 0);
response.AddAnswer(
new SrvRecord(
new ResourceRecordInfo(fullQuery, ResourceRecordType.SRV, QueryClass.IN, 1000, 0),
prio,
weight,
port,
DnsString.Parse(serviceName)));
var targetHost = DnsString.Parse("myservice.localhost.net");
response.AddAdditional(
new CNameRecord(
new ResourceRecordInfo(serviceName, ResourceRecordType.CNAME, QueryClass.IN, 1000, 0),
targetHost));
var client = new LookupClient(ns);
var mock = new Mock <IDnsQuery>();
mock.Setup(p => p.QueryAsync(It.IsAny <string>(), It.IsAny <QueryType>(), It.IsAny <QueryClass>(), It.IsAny <CancellationToken>()))
.Returns(() => Task.FromResult <IDnsQueryResponse>(response.AsQueryResponse(ns, client.Settings)));
var mockClient = mock.Object;
var result = await mockClient.ResolveServiceAsync(baseName, serviceName);
Assert.Single(result);
var first = result.First();
Assert.Equal(targetHost.ToString(), first.HostName);
Assert.Equal((int)port, first.Port);
Assert.Equal((int)prio, first.Priority);
Assert.Equal((int)weight, first.Weight);
}
public void Cache_EntriesLowestTTLWins()
{
var cache = new ResponseCache(true);
var record = new EmptyRecord(new ResourceRecordInfo("a", ResourceRecordType.A, QueryClass.IN, 1000, 100));
var recordB = new EmptyRecord(new ResourceRecordInfo("a", ResourceRecordType.A, QueryClass.IN, 100, 100));
var recordC = new EmptyRecord(new ResourceRecordInfo("a", ResourceRecordType.A, QueryClass.IN, 0, 100));
var response = new DnsResponseMessage(new DnsResponseHeader(1, 256, 1, 1, 0, 0), 0);
response.AddAnswer(record);
response.AddAdditional(recordB);
response.AddAuthority(recordC);
cache.Add("key", response.AsQueryResponse(new NameServer(IPAddress.Any)));
var item = cache.Get("key");
// should be null because recordC has zero TTL which wins
Assert.Null(item);
}
public void Cache_EntriesLowestTTLWins()
{
var cache = new ResponseCache();
var record = new EmptyRecord(new ResourceRecord(DnsString.Parse("a"), ARecord.ResourceRecordType, QueryClass.In, 1000, 100));
var recordB = new EmptyRecord(new ResourceRecord(DnsString.Parse("a"), ARecord.ResourceRecordType, QueryClass.In, 100, 100));
var recordC = new EmptyRecord(new ResourceRecord(DnsString.Parse("a"), ARecord.ResourceRecordType, QueryClass.In, 0, 100));
var response = new DnsResponseMessage(new DnsResponseHeader(1, 256, 1, 1, 0, 0), 0)
{
Audit = new LookupClientAudit()
};
response.AddAnswer(record);
response.AddAdditional(recordB);
response.AddAuthority(recordC);
cache.Add("key", response.AsQueryResponse(new NameServer(IPAddress.Any)));
var item = cache.Get("key", out var effectiveTtl);
// should be null because recordC has zero TTL which wins
Assert.Null(item);
Assert.Null(effectiveTtl);
}