public List<LookupRequest> Duplicates; // if any DNS lookup requests arrive with the same query they will be stored with the queued query.
public LookupRequest(string hostname, DNSQType queryType, int timeout, List<IPEndPoint> dnsServers, ManualResetEvent completeEvent)
{
Hostname = hostname;
QueryType = queryType;
Timeout = timeout;
DNSServers = dnsServers;
CompleteEvent = completeEvent;
}
/// <summary>
/// Do an QClass=IN Query on specified DNS servers
/// </summary>
/// <param name="name">Name to query</param>
/// <param name="qtype">Question type</param>
/// <param name="timeout">Timeout for lookup in seconds.</param>
/// <returns>Response of the query</returns>
public DNSResponse Query(string name, DNSQType qtype, int timeout)
{
Question question = new Question(name, qtype, QClass.IN);
DNSResponse response = SearchInCache(question);
if (response != null)
{
return(response);
}
DNSRequest request = new DNSRequest();
request.AddQuestion(question);
return(GetResponse(request, m_DnsServers, timeout));
}
public DNSResponse Query(string name, DNSQType qtype, int timeout, List<IPEndPoint> dnsServers)
{
Question question = new Question(name, qtype, QClass.IN);
DNSResponse response = SearchInCache(question);
if (response != null)
return response;
DNSRequest request = new DNSRequest();
request.AddQuestion(question);
return GetResponse(request, dnsServers, timeout);
}
/// <summary>
/// Do Query on specified DNS servers
/// </summary>
/// <param name="name">Name to query</param>
/// <param name="qtype">Question type</param>
/// <param name="timeout">Timeout for lookup in seconds.</param>
/// <param name="qclass">Class type</param>
/// <returns>Response of the query</returns>
public DNSResponse Query(string name, DNSQType qtype, QClass qclass, int timeout)
{
Question question = new Question(name, qtype, qclass);
DNSResponse response = SearchInCache(question);
if (response != null)
return response;
DNSRequest request = new DNSRequest();
request.AddQuestion(question);
return GetResponse(request, m_DnsServers, timeout);
}
/// <summary>
/// Do an QClass=IN Query on the previously cached results.
/// </summary>
/// <param name="name">Name to query</param>
/// <param name="qtype">Question type</param>
/// <returns>Response of the query</returns>
public DNSResponse QueryCache(string name, DNSQType qtype, QClass qclass)
{
Question question = new Question(name, qtype, qclass);
return SearchInCache(question);
}
/// <summary>
/// Do an QClass=IN Query on the previously cached results.
/// </summary>
/// <param name="name">Name to query</param>
/// <param name="qtype">Question type</param>
/// <returns>Response of the query</returns>
public DNSResponse QueryCache(string name, DNSQType qtype, QClass qclass)
{
Question question = new Question(name, qtype, qclass);
return(SearchInCache(question));
}
public static DNSResponse LookupAsync(string hostname, DNSQType queryType)
{
int lookupTimeout = (queryType == DNSQType.A || queryType == DNSQType.AAAA) ? DEFAULT_A_RECORD_DNS_TIMEOUT : DEFAULT_DNS_TIMEOUT;
return Lookup(hostname, queryType, lookupTimeout, null, true, true);
}
public Question(string QName, DNSQType QType, QClass QClass)
{
this.QName = QName;
this.QType = QType;
this.QClass = QClass;
}
/// <summary>
/// This method will wait until either the lookup completes or the timeout is reached before returning.
/// </summary>
/// <param name="hostname">The hostname of the A record to lookup in DNS.</param>
/// <param name="timeout">Timeout in seconds for the lookup.</param>
/// <returns></returns>
public static DNSResponse Lookup(string hostname, DNSQType queryType, int timeout, List<IPEndPoint> dnsServers)
{
return Lookup(hostname, queryType, timeout, dnsServers, true, false);
}
public static DNSResponse Lookup(string hostname, DNSQType queryType, int timeout, List <IPEndPoint> dnsServers, bool useCache, bool async)
{
if (hostname == null || hostname.Trim().Length == 0)
{
return(null);
}
DNSResponse ipAddressResult = MatchIPAddress(hostname);
if (ipAddressResult != null)
{
return(ipAddressResult);
}
else if (useCache)
{
DNSResponse cacheResult = m_resolver.QueryCache(hostname.Trim().ToLower(), queryType);
if (cacheResult != null)
{
return(cacheResult);
}
}
if (async)
{
//logger.Debug("DNS lookup cache miss for async lookup to " + queryType.ToString() + " " + hostname + ".");
QueueLookup(new LookupRequest(hostname.Trim().ToLower(), queryType, timeout, dnsServers, null));
return(null);
}
else
{
ManualResetEvent completeEvent = new ManualResetEvent(false);
QueueLookup(new LookupRequest(hostname.Trim().ToLower(), queryType, timeout, dnsServers, completeEvent));
if (completeEvent.WaitOne(timeout * 1000 * 2, false))
{
//logger.Debug("Complete event fired for DNS lookup on " + queryType.ToString() + " " + hostname + ".");
// Completed event was fired, the DNS entry will now be in cache.
DNSResponse result = m_resolver.QueryCache(hostname, queryType);
if (result != null)
{
return(result);
}
else
{
//logger.Debug("DNS lookup cache miss for " + queryType.ToString() + " " + hostname + ".");
// Timeout.
DNSResponse timeoutResponse = new DNSResponse();
timeoutResponse.Timedout = true;
return(timeoutResponse);
}
}
else
{
// If this block gets called it's because the DNS resolver class did not return within twice the timeout period it
// was asked to do so in. If this happens a lot further investigation into the DNS resolver class is warranted.
logger.Error("DNSManager timed out waiting for the DNS resolver to complete the lookup for " + queryType.ToString() + " " + hostname + ".");
// Timeout.
DNSResponse timeoutResponse = new DNSResponse();
timeoutResponse.Timedout = true;
return(timeoutResponse);
}
}
}
/// <summary>
/// This method will wait until either the lookup completes or the timeout is reached before returning.
/// </summary>
/// <param name="hostname">The hostname of the A record to lookup in DNS.</param>
/// <param name="timeout">Timeout in seconds for the lookup.</param>
/// <returns></returns>
public static DNSResponse Lookup(string hostname, DNSQType queryType, int timeout, List <IPEndPoint> dnsServers)
{
return(Lookup(hostname, queryType, timeout, dnsServers, true, false));
}
public static DNSResponse LookupAsync(string hostname, DNSQType queryType)
{
int lookupTimeout = (queryType == DNSQType.A || queryType == DNSQType.AAAA) ? DEFAULT_A_RECORD_DNS_TIMEOUT : DEFAULT_DNS_TIMEOUT;
return(Lookup(hostname, queryType, lookupTimeout, null, true, true));
}
public Question(RecordReader rr)
{
QName = rr.ReadDomainName();
QType = (DNSQType)rr.ReadShort();
QClass = (QClass)rr.ReadShort();
}
public Question(string QName, DNSQType QType, QClass QClass)
{
this.QName = QName;
this.QType = QType;
this.QClass = QClass;
}
public static DNSResponse Lookup(string hostname, DNSQType queryType, int timeout, List<IPEndPoint> dnsServers, bool useCache, bool async)
{
if (hostname == null || hostname.Trim().Length == 0)
{
return null;
}
DNSResponse ipAddressResult = MatchIPAddress(hostname);
if (ipAddressResult != null)
{
return ipAddressResult;
}
else if (useCache)
{
DNSResponse cacheResult = m_resolver.QueryCache(hostname.Trim().ToLower(), queryType);
if (cacheResult != null)
{
return cacheResult;
}
}
if (async)
{
//logger.Debug("DNS lookup cache miss for async lookup to " + queryType.ToString() + " " + hostname + ".");
QueueLookup(new LookupRequest(hostname.Trim().ToLower(), queryType, timeout, dnsServers, null));
return null;
}
else
{
ManualResetEvent completeEvent = new ManualResetEvent(false);
QueueLookup(new LookupRequest(hostname.Trim().ToLower(), queryType, timeout, dnsServers, completeEvent));
if (completeEvent.WaitOne(timeout * 1000 * 2, false))
{
//logger.Debug("Complete event fired for DNS lookup on " + queryType.ToString() + " " + hostname + ".");
// Completed event was fired, the DNS entry will now be in cache.
DNSResponse result = m_resolver.QueryCache(hostname, queryType);
if (result != null)
{
return result;
}
else
{
//logger.Debug("DNS lookup cache miss for " + queryType.ToString() + " " + hostname + ".");
// Timeout.
DNSResponse timeoutResponse = new DNSResponse();
timeoutResponse.Timedout = true;
return timeoutResponse;
}
}
else
{
// If this block gets called it's because the DNS resolver class did not return within twice the timeout period it
// was asked to do so in. If this happens a lot further investigation into the DNS resolver class is warranted.
logger.Error("DNSManager timed out waiting for the DNS resolver to complete the lookup for " + queryType.ToString() + " " + hostname + ".");
// Timeout.
DNSResponse timeoutResponse = new DNSResponse();
timeoutResponse.Timedout = true;
return timeoutResponse;
}
}
}
public Question(RecordReader rr)
{
QName = rr.ReadDomainName();
QType = (DNSQType)rr.ReadShort();
QClass = (QClass)rr.ReadShort();
}
private void VerboseDNSLookup(string host, DNSQType queryType) {
AppendTraceMessage("Looking up " + host + " query type " + queryType.ToString() + ".\n");
try {
//DNSResponse dnsResponse = DNSManager.Lookup(host, queryType, 5, new List<IPEndPoint>{new IPEndPoint(IPAddress.Parse("128.59.16.20"), 53)}, false, false);
DNSResponse dnsResponse = DNSManager.Lookup(host, queryType, 5, null, false, false);
if (dnsResponse.Error == null) {
List<AnswerRR> records = dnsResponse.Answers;
//if (records.Count > 0)
if (dnsResponse.RecordNAPTR.Length > 0) {
AppendTraceMessage("Results for " + host + " query type " + queryType.ToString() + ".\n");
//foreach (AnswerRR record in records)
foreach (RecordNAPTR record in dnsResponse.RecordNAPTR) {
AppendTraceMessage(record.ToString() + "\n");
}
}
else {
AppendTraceMessage("Empty result returned for " + host + " query type " + queryType.ToString() + ".\n");
}
}
else {
AppendTraceMessage("DNS lookup error for " + host + " query type " + queryType.ToString() + ", " + dnsResponse.Error + ".\n");
}
}
catch (ApplicationException appExcp) {
AppendTraceMessage(appExcp.Message);
}
}
