/**
* Get the service types from a single domain.
* @param domainName the domain to browse.
* @return a list of service types.
*/
private List <ServiceType> getServiceTypes(DomainName domainName)
{
List <ServiceType> results = new List <ServiceType>();
DnsMessage dnsMessage = DNSClientUtil.GetDefaultClient().Resolve(SERVICES_DNSSD_UDP + domainName, RecordType.Ptr);
if ((dnsMessage == null) || dnsMessage.AnswerRecords.Count == 0 || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
{
throw new Exception("DNS request failed");
}
else
{
foreach (DnsRecordBase record in dnsMessage.AnswerRecords)
{
PtrRecord ptr = record as PtrRecord;
DomainName name = ptr.PointerDomainName;
String type = name.Labels[0];
String transport = name.Labels[1];
results.Add(new ServiceType(type, transport));
}
}
return(results);
}
/**
* Get all service names of a specific type in a single domain.
* @param type the service type as a string, including transport and subtype (if any).
* @param domainName the domain to browse.
* @param results a collection to put found service names into.
*/
private void getServiceInstances(String type, DomainName domainName, ICollection <ServiceName> results)
{
DomainName typeDN = DomainName.Parse(type);
DomainName typeDomainName = typeDN + domainName;
DnsMessage dnsMessage = DNSClientUtil.GetDefaultClient().Resolve(typeDomainName, RecordType.Ptr);
if ((dnsMessage == null) || dnsMessage.AnswerRecords.Count == 0 || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
{
throw new Exception("DNS request failed");
}
else
{
foreach (DnsRecordBase record in dnsMessage.AnswerRecords)
{
PtrRecord ptr = record as PtrRecord;
DomainName name = ptr.PointerDomainName;
try
{
results.Add(ServiceName.fromDnsName(name));
}
catch (ArgumentException e)
{
Log.Error("Invalid service instance " + name + ": " + e.Message, e);
}
}
}
}
/**
* Create a DNS {@link Resolver} to handle updates to the given domain.
* @param domain the domain for which updates will be generated.
* @return a Resolver configured with the DNS server that handles zone for that domain.
* @throws UnknownHostException if the DNS server name for the domain failed to resolve.
*/
private DnsClient findUpdateResolver(DomainName domain)
{
DnsClient dnsClient = null;
DnsMessage dnsMessage = DNSClientUtil.GetDefaultClient().Resolve(DNSUPDATE_UDP + domain, RecordType.Srv);
if ((dnsMessage == null) || dnsMessage.AnswerRecords.Count == 0 || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
{
throw new Exception("DNS request failed");
}
else
{
foreach (DnsRecordBase record in dnsMessage.AnswerRecords)
{
SrvRecord srv = record as SrvRecord;
IPAddress[] address = Dns.GetHostAddresses(srv.Target.ToString());
dnsClient = new DnsClient(address, 10000);
Log.Info(String.Format("Using DNS server {0} to perform updates.", address));
break;
}
}
if (dnsClient == null)
{
dnsClient = DNSClientUtil.GetDefaultClient();
}
return(dnsClient);
}
/**
* Get all domains pointed to by the given resource record name,
* looking in a single computer domain.
* @param rrName the DNS resource record name.
* @return a collection of domain names.
*/
private List <String> getDomains(DomainName rrName, DomainName domainName)
{
List <String> results = new List <String>();
DnsMessage dnsMessage = DNSClientUtil.GetDefaultClient().Resolve(rrName + domainName, RecordType.Ptr);
if ((dnsMessage == null) || dnsMessage.AnswerRecords.Count == 0 || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
{
throw new Exception("DNS request failed");
}
else
{
foreach (DnsRecordBase record in dnsMessage.AnswerRecords)
{
PtrRecord ptr = record as PtrRecord;
DomainName name = ptr.PointerDomainName;
results.Add(name.ToString());
}
}
return(results);
}
public ServiceData getServiceData(ServiceName service)
{
DomainName serviceName = service.toDnsName();
DnsMessage dnsMessage = DNSClientUtil.GetDefaultClient().Resolve(serviceName, RecordType.Srv);
if ((dnsMessage == null) || dnsMessage.AnswerRecords.Count == 0 || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
{
return(null);
}
ServiceData data = new ServiceData();
data.setName(service);
foreach (DnsRecordBase record in dnsMessage.AnswerRecords)
{
// TODO Handle priority and weight correctly in case of multiple SRV record.
SrvRecord srv = record as SrvRecord;
data.setHost(srv.Target.ToString());
data.setPort(srv.Port);
break;
}
dnsMessage = DNSClientUtil.GetDefaultClient().Resolve(serviceName, RecordType.Txt);
if ((dnsMessage == null) || dnsMessage.AnswerRecords.Count == 0 || ((dnsMessage.ReturnCode != ReturnCode.NoError) && (dnsMessage.ReturnCode != ReturnCode.NxDomain)))
{
return(data);
}
foreach (DnsRecordBase record in dnsMessage.AnswerRecords)
{
// TODO Handle multiple TXT records as different variants of same service
TxtRecord txt = record as TxtRecord;
foreach (String str in txt.TextParts)
{
// Safe cast
int i = str.IndexOf('=');
String key;
String value;
if (i == 0 || str.Equals(""))
{
continue; // Invalid empty key, should be ignored
}
else if (i > 0)
{
key = str.Substring(0, i).ToLower();
value = str.Substring(i + 1);
}
else
{
key = str;
value = null;
}
if (!data.getProperties().ContainsKey(key)) // Ignore all but the first
{
data.getProperties()[key] = value;
}
}
break;
}
return(data);
}