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);
}
/** * Add a new service to DNS-SD. * If the service name is already taken this method will not update the service data, * but return false to indicate the collision. * @param serviceData the service to register. * @return true if the service was registered, false if the service name was already registered. * @throws DnsSDException if the service couldn't be registered due to some error. */ public abstract bool registerService(ServiceData serviceData);
public override bool registerService(ServiceData serviceData)
{
ServiceName serviceName = serviceData.getName();
DomainName dnsName = serviceName.toDnsName();
DomainName typeName = DomainName.Parse(serviceName.getType().toDnsString()) + registrationDomain;
List <DomainName> subtypes = new List <DomainName>(serviceName.getType().getSubtypes().Count);
foreach (String subtype in serviceName.getType().toDnsStringsWithSubtype())
{
subtypes.Add(DomainName.Parse(subtype) + registrationDomain);
}
DomainName target = DomainName.Parse(serviceData.getHost());
List <String> strings = new List <String>();
foreach (var entry in serviceData.getProperties())
{
StringBuilder sb = new StringBuilder();
sb.Append(entry.Key);
if (entry.Key != null)
{
sb.Append('=').Append(entry.Value);
}
strings.Add(sb.ToString());
}
if (strings.Count <= 0)
{
// Must not be empty
strings.Add("");
}
DnsUpdateMessage msg = new DnsUpdateMessage();
msg.ZoneName = registrationDomain; // XXX Should really be the zone (SOA) for the RRs we are about to add
msg.Prequisites.Add(new RecordNotExistsPrequisite(dnsName, RecordType.Any));
msg.Updates.Add(new AddRecordUpdate(new PtrRecord(servicesName, timeToLive, typeName)));
msg.Updates.Add(new AddRecordUpdate(new PtrRecord(typeName, timeToLive, dnsName)));
foreach (DomainName subtype in subtypes)
{
msg.Updates.Add(new AddRecordUpdate(new PtrRecord(subtype, timeToLive, dnsName)));
}
msg.Updates.Add(new AddRecordUpdate(new SrvRecord(dnsName, timeToLive, 0, 0, Convert.ToUInt16(serviceData.getPort()), target)));
msg.Updates.Add(new AddRecordUpdate(new TxtRecord(dnsName, timeToLive, strings)));
TSigRecord tsigRecord = generateTSigRecord(msg.TransactionID);
if (tsigRecord != null)
{
msg.TSigOptions = tsigRecord;
}
DnsUpdateMessage response = resolver.SendUpdate(msg);
if (response != null)
{
switch (response.ReturnCode)
{
case ReturnCode.NoError:
//flushCache(update);
return(true);
case ReturnCode.YXDomain: // Prerequisite failed, the service already exists.
return(false);
default:
throw new DnsSDException("Failed to send DNS update to server. Server returned error code: " + response.ReturnCode.ToString());
}
}
else
{
throw new DnsSDException("Failed to send DNS update to server. Server time out");
}
}
