public static SIPDNSLookupResult DNSARecordLookup(string host, int port, bool async, SIPURI uri)
{
SIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.Unknown, SIPMonitorEventTypesEnum.DNS, "SIP DNS A record lookup requested for " + host + ".", null));
SIPDNSLookupResult result = new SIPDNSLookupResult(uri);
DNSResponse aRecordResponse = DNSManager.Lookup(host, DNSQType.A, DNS_A_RECORD_LOOKUP_TIMEOUT, null, true, async);
if (aRecordResponse == null && async)
{
result.Pending = true;
}
else if (aRecordResponse.Timedout)
{
result.ATimedoutAt = DateTime.Now;
}
else if (aRecordResponse.Error != null)
{
result.LookupError = aRecordResponse.Error;
}
else if (aRecordResponse.RecordsA == null || aRecordResponse.RecordsA.Length == 0)
{
SIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.Unknown, SIPMonitorEventTypesEnum.DNS, "SIP DNS no A records found for " + host + ".", null));
result.LookupError = "No A records found for " + host + ".";
}
else
{
SIPURI sipURI = result.URI;
foreach (RecordA aRecord in aRecordResponse.RecordsA)
{
SIPDNSLookupEndPoint sipLookupEndPoint = new SIPDNSLookupEndPoint(new SIPEndPoint(sipURI.Protocol, new IPEndPoint(aRecord.Address, port)), aRecord.RR.TTL);
result.AddLookupResult(sipLookupEndPoint);
SIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.Unknown, SIPMonitorEventTypesEnum.DNS, "SIP DNS A record found for " + host + ", result " + sipLookupEndPoint.LookupEndPoint.ToString() + ".", null));
}
}
return(result);
}
public static SIPDNSLookupResult ResolveSIPService(SIPURI sipURI, bool async)
{
try
{
if (sipURI == null)
{
throw new ArgumentNullException("sipURI", "Cannot resolve SIP service on a null URI.");
}
string host = sipURI.Host;
int port = (sipURI.Scheme == SIPSchemesEnum.sip) ? m_defaultSIPPort : m_defaultSIPSPort;
bool explicitPort = false;
if (sipURI.Host.IndexOf(':') != -1)
{
host = sipURI.Host.Split(':')[0];
Int32.TryParse(sipURI.Host.Split(':')[1], out port);
explicitPort = true;
}
if (Regex.Match(host, @"^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$").Success)
{
// Target is an IP address, no DNS lookup required.
IPAddress hostIP = IPAddress.Parse(host);
SIPDNSLookupEndPoint sipLookupEndPoint = new SIPDNSLookupEndPoint(new SIPEndPoint(sipURI.Protocol, new IPEndPoint(hostIP, port)), 0);
SIPDNSLookupResult result = new SIPDNSLookupResult(sipURI);
result.AddLookupResult(sipLookupEndPoint);
return(result);
}
else if (explicitPort)
{
// Target is a hostname with an explicit port, DNS lookup for A or AAAA record.
return(DNSARecordLookup(host, port, async, sipURI));
}
else
{
// Target is a hostname with no explicit port, use the whole NAPTR->SRV->A lookup procedure.
SIPDNSLookupResult sipLookupResult = new SIPDNSLookupResult(sipURI);
// Do without the NAPTR lookup for the time being. Very few organisations appear to use them and it can cost up to 2.5s to get a failed resolution.
/*SIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.Unknown, SIPMonitorEventTypesEnum.DNS, "SIP DNS full lookup requested for " + sipURI.ToString() + ".", null));
* DNSNAPTRRecordLookup(host, async, ref sipLookupResult);
* if (sipLookupResult.Pending)
* {
* if (!m_inProgressSIPServiceLookups.Contains(sipURI.ToString()))
* {
* m_inProgressSIPServiceLookups.Add(sipURI.ToString());
* ThreadPool.QueueUserWorkItem(delegate { ResolveSIPService(sipURI, false); });
* }
* return sipLookupResult;
* }*/
DNSSRVRecordLookup(sipURI.Scheme, sipURI.Protocol, host, async, ref sipLookupResult);
if (sipLookupResult.Pending)
{
//logger.Debug("SIPDNSManager SRV lookup for " + host + " is pending.");
return(sipLookupResult);
}
else
{
//logger.Debug("SIPDNSManager SRV lookup for " + host + " is final.");
SIPDNSServiceResult nextSRVRecord = sipLookupResult.GetNextUnusedSRV();
int lookupPort = (nextSRVRecord != null) ? nextSRVRecord.Port : port;
return(DNSARecordLookup(nextSRVRecord, host, lookupPort, async, sipLookupResult.URI));
}
}
}
catch (Exception excp)
{
logger.Error("Exception SIPDNSManager ResolveSIPService (" + sipURI.ToString() + "). " + excp.Message);
m_inProgressSIPServiceLookups.Remove(sipURI.ToString());
return(new SIPDNSLookupResult(sipURI, excp.Message));
}
}