public async Task ItShouldLogErrorWhenUnableToDoLookupForPtr(string ipAddress)
{
ReverseDnsQueryResponse response = new ReverseDnsQueryResponse(true, "Something has gone wrong!", null);
A.CallTo(() => _dnsResolver.QueryPtrAsync(A <IPAddress> ._)).Returns(response);
var reverseDnsLookup = new ReverseDnsLookup(_dnsResolver, _log);
ReverseDnsResult result = await reverseDnsLookup.Lookup(ipAddress);
Assert.That(_log.Warnings.Count, Is.EqualTo(1));
Assert.That(result.ForwardResponses.Count, Is.EqualTo(0));
Assert.IsNull(result.OriginalIpAddress);
}
private async Task <ReverseDnsResult> GetReverseDnsResult(IPAddress originalAddress)
{
int attempt = 0;
int maxAttempts = 5;
while (attempt < maxAttempts)
{
await Task.Delay(attempt *attempt * 1000);
attempt++;
try
{
ReverseDnsQueryResponse response = await _dnsResolver.QueryPtrAsync(originalAddress);
if (response.HasError && attempt < maxAttempts)
{
continue;
}
if (response.HasError)
{
_log.LogWarning("Failed to do PTR look up for {IpAddress} with error: {Error}.", originalAddress, response.ErrorMessage ?? "Unknown error");
return(ReverseDnsResult.InvalidReverseDnsResult);
}
List <string> hosts = response.Results;
List <ReverseDnsResponse> forwardResponses = originalAddress.AddressFamily == AddressFamily.InterNetwork
? await GetDnsResponses <ARecord>(hosts, QueryType.A)
: await GetDnsResponses <AaaaRecord>(hosts, QueryType.AAAA);
return(new ReverseDnsResult(originalAddress.ToString(), forwardResponses));
}
catch (Exception e)
{
string errorMessage = $"Error occured performing PTR lookup for {originalAddress} (attempt {attempt} of {maxAttempts})";
if (attempt == maxAttempts)
{
_log.LogError(e, errorMessage);
}
else
{
_log.LogWarning(e, errorMessage);
}
}
}
return(ReverseDnsResult.InvalidReverseDnsResult);
}
