public DnsEntry FindDnsEntryWithWildcard(IUnitOfWork uow, DnsRequest dnsRequest)
{
return Mapper.Map<Core.Models.DnsEntry>(uow.Db.FirstOrDefault<SQL.Models.DnsEntry>(
new Sql()
.Append("SELECT * FROM dns_entries dnsEntry")
.Append("WHERE @name LIKE dnsEntry.Name", new { name = dnsRequest.Name })
.Append("AND dnsEntry.Type = @type", new { type = dnsRequest.Type })
));
}
public void Should_Not_Resolve_Dns_Query_Because_No_Entry_Matches()
{
var dnsEntriesRepository = Mock.Of<IDnsEntriesRepository>();
var unitOfWorkProvider = Mock.Of<IUnitOfWorkProvider>();
IDnsResolver resolver = new DnsResolver(dnsEntriesRepository, unitOfWorkProvider);
DnsRequest dnsRequest = new DnsRequest() { Name = "test", Type="TXT" };
DnsResolutionResult result = resolver.Resolve(dnsRequest);
result.DnsEntry.Should().BeNull();
}
public void Should_Resolve_Dns_Query_Because_Entry_Matches_Exactly()
{
var dnsEntriesRepository = Mock.Of<IDnsEntriesRepository>(mock => mock.FindDnsEntry(It.IsAny<IUnitOfWork>(), It.IsAny<DnsRequest>()) == new DnsEntry());
var unitOfWorkProvider = Mock.Of<IUnitOfWorkProvider>();
IDnsResolver resolver = new DnsResolver(dnsEntriesRepository, unitOfWorkProvider);
DnsRequest dnsRequest = new DnsRequest() { Name = "test", Type = "TXT" };
DnsResolutionResult result = resolver.Resolve(dnsRequest);
result.DnsEntry.Should().NotBeNull();
}
private void ProcessQuestion(DnsMessage message, DnsQuestion dnsQuestion)
{
var dnsRequest = new DnsRequest() { Name = dnsQuestion.Name, Type = dnsQuestion.RecordType.ToString() };
var result = dnsResolver.Resolve(dnsRequest);
if (result.DnsEntry == null)
{
message.ReturnCode = ReturnCode.NxDomain;
return;
}
message.AnswerRecords.Add(new ARecord(dnsRequest.Name, 3600, IPAddress.Parse(result.DnsEntry.IpV4)));
}
public DnsResolutionResult Resolve(DnsRequest dnsRequest)
{
var result = new DnsResolutionResult();
using (var uow = unitOfWorkProvider.GetUnitOfWork())
{
result.DnsEntry = (dnsEntriesRepository.FindDnsEntry(uow, dnsRequest)
?? dnsEntriesRepository.FindDnsEntryWithWildcard(uow, dnsRequest))
?? CheckCache(dnsRequest)
?? ForwardRequest(dnsRequest);
}
return result;
}
private DnsEntry ForwardRequestToServer(DnsRequest dnsRequest, ForwardingServer forwardingServer, RecordType recordType)
{
var client = new DnsClient(IPAddress.Parse(forwardingServer.IpV4), 2000);
var answer = client.Resolve(dnsRequest.Name, recordType);
if (answer != null && answer.AnswerRecords.Any())
{
var record = answer.AnswerRecords.FirstOrDefault(r => r.RecordType == recordType);
//if (record.RecordType != RecordType.A)
// return null;
if (record == null)
return null;
if (record.RecordType != RecordType.A)
return null;
var dnsEntry = new DnsEntry() { Name = record.Name, IpV4 = ((ARecord)record).Address.ToString() };
return dnsEntry;
}
return null;
}
private DnsEntry ForwardRequest(DnsRequest dnsRequest)
{
using (var uow = unitOfWorkProvider.GetUnitOfWork())
{
var recordType = ParseRecordType(dnsRequest.Type);
var forwardingServers = forwardingServersRepository.GetAllForwardingServers(uow);
foreach (var forwardingServer in forwardingServers)
{
var dnsEntry = ForwardRequestToServer(dnsRequest, forwardingServer, recordType);
if (dnsEntry != null)
{
if (!Cache.ContainsKey(dnsEntry.Name))
Cache.Add(dnsEntry.Name, dnsEntry);
else
Cache[dnsEntry.Name] = dnsEntry;
return dnsEntry;
}
}
return null;
}
}
private DnsEntry CheckCache(DnsRequest dnsRequest)
{
DnsEntry dnsEntry;
return Cache.TryGetValue(dnsRequest.Name, out dnsEntry) ? dnsEntry : null;
}
