/// <summary>
/// Gets the DNS records of a domain.
/// /// </summary>
/// <param name="domain">Domain to query for DNS records</param>
/// <param name="localDNSIPs">List of local DNS Resolver IPs to do the lookup</param>
/// <returns></returns>
public async Task <CollatedRecords> GetRecordsOfDomain(Uri domain, List <IPAddress> localDNSIPs)
{
IList <IPAddress> respIPs = new List <IPAddress>();
IResponse resp = null;
foreach (var dnsIP in localDNSIPs)
{
DnsClient cli = new DnsClient(dnsIP);
ClientRequest req = cli.Create();
req.RecursionDesired = true;
req.Questions.Add(new Question(Domain.FromString(domain.Host), RecordType.ANY));
try {
resp = await req.Resolve();
respIPs = await cli.Lookup(domain.Host);
} catch {
Console.Error.WriteLine("Swallowed lookup exception.");
}
if (resp != null && resp.ResponseCode.Equals(ResponseCode.NoError))
{
break;
}
}
if (resp == null)
{
throw new InvalidOperationException("Unable to get a valid response from the domain, check input.");
}
return(new CollatedRecords(resp, respIPs));
}
protected virtual IResponse ResolveRemote(Request request)
{
Console.WriteLine("Request From: " + local.Address.ToString());
ClientRequest remoteRequest = client.Create(request);
ClientResponse response = remoteRequest.Resolve();
return(response);
}
protected virtual IResponse ResolveRemote(Request request)
{
// WARNING: this function is called from a worker thread
if (resolver == null)
{
return(null);
}
ClientRequest remoteRequest = resolver.Create(request);
return(remoteRequest.Resolve());
}
public static async Task Run([TimerTrigger("0 0 * * * *")] TimerInfo myTimer, ILogger log, CancellationToken cancellationToken)
{
log.LogInformation($"Checking for Old or Deleted Students: {DateTime.Now}");
var credentials = SdkContext.AzureCredentialsFactory.FromMSI(new MSILoginInformation(MSIResourceType.AppService), AzureEnvironment.AzureGlobalCloud);
var azure = Azure.Configure()
.WithLogLevel(HttpLoggingDelegatingHandler.Level.Basic)
.Authenticate(credentials)
.WithDefaultSubscription();
var zone = await azure.DnsZones.GetByResourceGroupAsync("rg-contosomasks", "contosomasks.com");
var allNSRecords = await zone.NSRecordSets.ListAsync(true, cancellationToken);
if (allNSRecords != null && allNSRecords.Any(ns => !ns.Name.Equals("@")))
{
DnsClient client = new DnsClient("8.8.8.8");
foreach (var ns in allNSRecords.Where(ns => !ns.Name.Equals("@")))
{
var request = client.Create();
request.Questions.Add(new DNS.Protocol.Question(Domain.FromString($"donotdelete.{ns.Name}.contosomasks.com"), RecordType.TXT));
request.RecursionDesired = true;
bool found = false;
try
{
var response = await request.Resolve();
found = response.AnswerRecords != null && response.AnswerRecords.Any();
}
catch (Exception)
{
found = false;
}
if (!found)
{
log.LogInformation($"Student {ns.Name} is done, removing subdomain");
await zone.Update().WithoutNSRecordSet(ns.Name).ApplyAsync();
}
else
{
log.LogInformation($"Student {ns.Name} is still active");
}
}
}
}
static async void Run()
{
try
{
// Bind to a Domain Name Server
DnsClient client = new DnsClient("8.8.8.8");
// Create request bound to 8.8.8.8
ClientRequest request = client.Create();
// Returns a list of IPs
IList <IPAddress> ips = await client.Lookup("framesoft.ir");
// Get the domain name belonging to the IP (google.com)
//string domain = await client.Reverse("173.194.69.100");
}
catch (Exception ex)
{
}
}
protected virtual IResponse ResolveRemote(Request request)
{
ClientRequest remoteRequest = client.Create(request);
return(remoteRequest.Resolve());
}
protected virtual async Task <IResponse> ResolveRemote(Request request)
{
ClientRequest remoteRequest = client.Create(request);
return(await remoteRequest.Resolve());
}
private async Task ResolveName(InConnectionDns cxn)
{
var name = cxn.Dest.Host;
var req = dnsClient.Create();
var domain = new Domain(name);
req.Questions.Add(new Question(domain, cxn.RequestType != DnsRequestType.AAAA ? RecordType.A : RecordType.AAAA));
req.OperationCode = OperationCode.Query;
req.RecursionDesired = true;
IResponse r;
try {
r = await req.Resolve();
} catch (ResponseException e) {
var emptyResp = DnsResponse.Empty(this);
emptyResp.Result = ConnectResultEnum.Failed;
emptyResp.FailedReason = e.Message;
await cxn.SetResult(emptyResp);
return;
}
if (r.ResponseCode != ResponseCode.NoError)
{
Logger.warning("resolving " + name + ": server returns " + r.ResponseCode);
}
int count = 0;
foreach (var item in r.AnswerRecords)
{
if (item.Type == RecordType.A || item.Type == RecordType.AAAA)
{
count++;
}
}
if (count == 0)
{
if (r.AnswerRecords.Count == 0)
{
Logger.warning("resolving " + name + ": no answer records");
}
else
{
Logger.warning("resolving " + name + ": answer records without A/AAAA records");
}
}
var arr = new IPAddress[count];
int?ttl = null;
int cur = 0;
foreach (var item in r.AnswerRecords)
{
if (item.Type == RecordType.A || item.Type == RecordType.AAAA)
{
arr[cur++] = ((IPAddressResourceRecord)item).IPAddress;
int newTtl = (int)item.TimeToLive.TotalSeconds;
ttl = ttl.HasValue ? Math.Min(newTtl, ttl.Value) : newTtl;
}
}
var resp = new DnsResponse(this, arr)
{
TTL = ttl
};
await cxn.SetResult(resp);
}