private NetService ProcessPTRRecord(PTRRecord record)
{
if (record.Name != _currentServiceType)
{
return(null);
}
NetService service = null;
string serviceInstanceName = record.DomainName;
// TTL of zero means we need to remove the service from the list
if (record.TimeToLive == TimeSpan.Zero)
{
RemoveService(serviceInstanceName);
return(null);
}
if (_discoveredServices.ContainsKey(serviceInstanceName))
{
service = _discoveredServices[serviceInstanceName];
}
else
{
service = new NetService(this);
service.FullServiceInstanceName = serviceInstanceName;
lock (_discoveredServices)
_discoveredServices[serviceInstanceName] = service;
}
service.TTLExpires = DateTime.Now + record.TimeToLive;
return(service);
}
/// <summary>
/// Advertise a service profile.
/// </summary>
/// <param name="service">
/// The service profile.
/// </param>
/// <remarks>
/// Any queries for the service or service instance will be answered with
/// information from the profile.
/// <para>
/// Besides adding the profile's resource records to the <see cref="Catalog"/> PTR records are
/// created to support DNS-SD and reverse address mapping (DNS address lookup).
/// </para>
/// </remarks>
public void Advertise(ServiceProfile service)
{
_profiles.Add(service);
var catalog = NameServer.Catalog;
catalog.Add(new PTRRecord {
Name = ServiceName, DomainName = service.QualifiedServiceName
}, true);
catalog.Add(new PTRRecord {
Name = service.QualifiedServiceName, DomainName = service.FullyQualifiedName
}, true);
foreach (var subtype in service.Subtypes)
{
var ptr = new PTRRecord
{
Name = DomainName.Join(new DomainName(subtype), SubName, service.QualifiedServiceName),
DomainName = service.FullyQualifiedName
};
catalog.Add(ptr, true);
}
foreach (var r in service.Resources)
{
catalog.Add(r, true);
}
catalog.IncludeReverseLookupRecords();
}
private void AnswerReceived(Message message)
{
List <PTRRecord> answers = message.Answers.Where(a => a.Name == AtemDeviceInfo.ServiceName).OfType <PTRRecord>().ToList();
PTRRecord answer = answers.FirstOrDefault();
if (answer == null)
{
return;
}
if (_debug && answers.Count != 1)
{
Console.WriteLine("Too many answers!");
}
List <ResourceRecord> records = message.AdditionalRecords;
SRVRecord srvRec = records.OfType <SRVRecord>().FirstOrDefault(r => r.Type == DnsType.SRV && r.Name == answer.DomainName);
if (srvRec == null)
{
if (_debug)
{
Console.WriteLine("Missing SRV record for " + answer.DomainName);
}
return;
}
AddressRecord aRec = records.OfType <AddressRecord>().FirstOrDefault(r => r.Type == DnsType.A && r.Name == srvRec.Target);
if (aRec == null)
{
if (_debug)
{
Console.WriteLine("Missing A record for " + answer.DomainName);
}
return;
}
TXTRecord txtRec = records.OfType <TXTRecord>().FirstOrDefault(r => r.Type == DnsType.TXT && r.Name == answer.DomainName);
List <string> strings = txtRec == null ? new List <string>() : txtRec.Strings;
string name = string.Join(".", answer.DomainName.Labels);
if (name.EndsWith(AtemDeviceInfo.ServiceName))
{
name = name.Substring(0, name.Length - AtemDeviceInfo.ServiceName.Length - 1);
}
var dev = new AtemDeviceInfo(name, srvRec.Target.ToString(), DateTime.Now, aRec.Address.ToString(), srvRec.Port, strings);
lock (_knownDevices) {
_knownDevices[dev.DeviceId] = dev;
}
OnDeviceSeen?.Invoke(this, dev);
}
private void ReverseDnsRecord(Output <string> resourceGroupName, Zone privateReverseDns, Output <string> ipAddress, int vnetRangePrefix)
{
var nodeRecord = new PTRRecord($"ptr-{DeploymentName}{vnetRangePrefix / 2 + 1}", new PTRRecordArgs
{
ResourceGroupName = resourceGroupName,
ZoneName = privateReverseDns.Name,
Name = ipAddress.Apply(ipAddress => ConstructReveseIpAddress(ipAddress, 3)),
Records = { $"{DeploymentName}{vnetRangePrefix / 2 + 1}.{ZoneName}" },
Ttl = 300
});
}
private PTRRecord DeserializePtrRr(string name, int ttl, byte[] bytes, int start, out int bytesRead)
{
var ptr = new PTRRecord()
{
Name = name,
TimeToLive = ttl,
};
ptr.PtrDName = this.dnsSerializer.ParseQuestionName(bytes, start, out bytesRead);
return(ptr);
}
/// <summary>
/// Add PTR records for each authoritative A/AAAA record.
/// </summary>
/// <remarks>
/// This enables reverse DNS lookup of all address records.
/// </remarks>
public void IncludeReverseLookupRecords()
{
var addressRecords = this.Values
.Where(node => node.Authoritative)
.SelectMany(node => node.Resources.OfType <AddressRecord>());
foreach (var a in addressRecords)
{
var ptr = new PTRRecord
{
Class = a.Class,
Name = new DomainName(a.Address.GetArpaName()),
DomainName = a.Name,
TTL = a.TTL
};
Add(ptr, authoritative: true);
}
}
public void DuplicateResources()
{
var node = new Node();
var a = new PTRRecord {
Name = "a", DomainName = "alpha"
};
var b = new PTRRecord {
Name = "a", DomainName = "alpha"
};
Assert.AreEqual(a, b);
node.Resources.Add(a);
node.Resources.Add(b);
node.Resources.Add(a);
node.Resources.Add(b);
Assert.AreEqual(1, node.Resources.Count);
}
/// <summary>
/// Sends an unsolicited MDNS response describing the
/// service profile.
/// </summary>
/// <param name="profile">
/// The profile to describe.
/// </param>
/// <remarks>
/// Sends a MDNS response <see cref="Message"/> containing the pointer
/// and resource records of the <paramref name="profile"/>.
/// <para>
/// To provide increased robustness against packet loss,
/// two unsolicited responses are sent one second apart.
/// </para>
/// </remarks>
public void Announce(ServiceProfile profile)
{
var message = new Message {
QR = true
};
// Add the shared records.
var ptrRecord = new PTRRecord {
Name = profile.QualifiedServiceName, DomainName = profile.FullyQualifiedName
};
message.Answers.Add(ptrRecord);
// Add the resource records.
profile.Resources.ForEach((resource) =>
{
message.Answers.Add(resource);
});
message.Questions.Add(new Question()
{
Name = profile.ServiceName,
Class = DnsClass.IN,
Type = DnsType.PTR
});
foreach (var ip in MulticastService.GetLinkLocalAddresses())
{
message.AdditionalRecords.Add(new ARecord()
{
Class = DnsClass.IN,
Type = DnsType.A,
Name = profile.ServiceName,
Address = ip,
TTL = TimeSpan.FromSeconds(120)
});
}
Mdns.Send(message, false);
Task.Delay(1000).Wait();
Mdns.Send(message, false);
}
private Message GetStopPublishMessage()
{
Message message = new Message();
ResourceRecord record;
// This message is a response
message.QueryResponse = true;
// This is an authoritative response
message.AuthoritativeAnswer = true;
// PTR Record
record = new PTRRecord()
{
TimeToLive = TimeSpan.Zero,
Name = Type,
DomainName = FullServiceInstanceName,
};
message.AnswerRecords.Add(record);
return(message);
}
/// <summary>
/// Sends a goodbye message for the provided
/// profile and removes its pointer from the name sever.
/// </summary>
/// <param name="profile">The profile to send a goodbye message for.</param>
public void Unadvertise(ServiceProfile profile)
{
var message = new Message {
QR = true
};
var ptrRecord = new PTRRecord {
Name = profile.QualifiedServiceName, DomainName = profile.FullyQualifiedName
};
ptrRecord.TTL = TimeSpan.Zero;
message.Answers.Add(ptrRecord);
profile.Resources.ForEach((resource) =>
{
resource.TTL = TimeSpan.Zero;
message.AdditionalRecords.Add(resource);
});
Mdns.SendAnswer(message);
NameServer.Catalog.TryRemove(profile.QualifiedServiceName, out Node _);
}
/// <summary>
/// Sends an unsolicited MDNS response describing the
/// service profile.
/// </summary>
/// <param name="profile">
/// The profile to describe.
/// </param>
/// <remarks>
/// Sends a MDNS response <see cref="Message"/> containing the pointer
/// and resource records of the <paramref name="profile"/>.
/// <para>
/// To provide increased robustness against packet loss,
/// two unsolicited responses are sent one second apart.
/// </para>
/// </remarks>
public void Announce(ServiceProfile profile)
{
var message = new Message {
QR = true
};
// Add the shared records.
var ptrRecord = new PTRRecord {
Name = profile.QualifiedServiceName, DomainName = profile.FullyQualifiedName
};
message.Answers.Add(ptrRecord);
// Add the resource records.
profile.Resources.ForEach((resource) =>
{
message.Answers.Add(resource);
});
Mdns.SendAnswer(message, checkDuplicate: false);
Task.Delay(1000).Wait();
Mdns.SendAnswer(message, checkDuplicate: false);
}
private Message GetPublishMessage(PublishMessageType type)
{
Message message = new Message();
ResourceRecord record;
// This message is a response
message.QueryResponse = true;
// This is an authoritative response
message.AuthoritativeAnswer = true;
// SRV Record
record = new SRVRecord()
{
TimeToLive = (type == PublishMessageType.Stop) ? TimeSpan.Zero : BroadcastTTL,
CacheFlush = true,
Name = FullServiceInstanceName,
Target = Hostname,
Port = Port,
};
message.AnswerRecords.Add(record);
// TXT Record
if (TXTRecordData != null && TXTRecordData.Count > 0)
{
record = new TXTRecord()
{
TimeToLive = (type == PublishMessageType.Stop) ? TimeSpan.Zero : BroadcastTTL,
CacheFlush = true,
Name = FullServiceInstanceName,
Data = TXTRecordData,
};
message.AnswerRecords.Add(record);
}
// PTR Record for DNS-SD Service Type Enumeration
if (type == PublishMessageType.Normal)
{
record = new PTRRecord()
{
TimeToLive = BroadcastTTL,
Name = BonjourUtility.DNSSDServiceTypeEnumerationName,
DomainName = Type,
};
message.AnswerRecords.Add(record);
}
// Service PTR Record
if (type != PublishMessageType.Initial)
{
record = new PTRRecord()
{
TimeToLive = (type == PublishMessageType.Stop) ? TimeSpan.Zero : BroadcastTTL,
Name = Type,
DomainName = FullServiceInstanceName,
};
message.AnswerRecords.Add(record);
}
// A Records
if (type != PublishMessageType.Stop)
{
foreach (var ip in IPAddresses)
{
record = new ARecord()
{
TimeToLive = BroadcastTTL,
CacheFlush = true,
Name = Hostname,
Address = ip,
};
message.AdditionalRecords.Add(record);
}
}
return(message);
}
