Class ServiceDiscovery

DNS based Service Discovery is a way of using standard DNS programming interfaces, servers, and packet formats to browse the network for services.

Inheritance

Object

ServiceDiscovery

Implements

IDisposable

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: Makaretu.Dns

Assembly: Makaretu.Dns.Multicast.dll

Syntax

public class ServiceDiscovery : IDisposable

Constructors

ServiceDiscovery()

Creates a new instance of the ServiceDiscovery class.

Declaration

public ServiceDiscovery()

ServiceDiscovery(MulticastService)

Creates a new instance of the ServiceDiscovery class with the specified MulticastService.

Declaration

public ServiceDiscovery(MulticastService mdns)

Parameters

Type	Name	Description
MulticastService	mdns	The underlaying MulticastService to use.

Fields

ServiceName

The service discovery service name.

Declaration

public static readonly DomainName ServiceName

Field Value

Type	Description
DomainName	The service name used to enumerate other services.

Properties

AnswersContainsAdditionalRecords

Add the additional records into the answers.

Declaration

public bool AnswersContainsAdditionalRecords { get; set; }

Property Value

Type	Description
Boolean	Defaults to false.

Remarks

Some malformed systems, such as js-ipfs and go-ipfs, only examine the Answers and not the AdditionalRecords. Setting this to true, will move the additional records into the answers.

This never done for DNS-SD answers.

Mdns

Gets the multicasting service.

Declaration

public MulticastService Mdns { get; }

Property Value

Type	Description
MulticastService	Is used to send and recieve multicast Message.

NameServer

Gets the name server.

Declaration

public NameServer NameServer { get; }

Property Value

Type	Description
NameServer	Is used to answer questions.

Methods

Advertise(ServiceProfile)

Advertise a service profile.

Declaration

public void Advertise(ServiceProfile service)

Parameters

Type	Name	Description
ServiceProfile	service	The service profile.

Remarks

Any queries for the service or service instance will be answered with information from the profile.

Besides adding the profile's resource records to the Catalog PTR records are created to support DNS-SD and reverse address mapping (DNS address lookup).

Announce(ServiceProfile)

Sends an unsolicited MDNS response describing the service profile.

Declaration

public void Announce(ServiceProfile profile)

Parameters

Type	Name	Description
ServiceProfile	profile	The profile to describe.

Remarks

Sends a MDNS response Message containing the pointer and resource records of the profile.

To provide increased robustness against packet loss, two unsolicited responses are sent one second apart.

Dispose()

Declaration

public void Dispose()

Dispose(Boolean)

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
Boolean	disposing

QueryAllServices()

Asks other MDNS services to send their service names.

Declaration

public void QueryAllServices()

Remarks

When an answer is received the ServiceDiscovered event is raised.

QueryServiceInstances(DomainName)

Asks instances of the specified service to send details.

Declaration

public void QueryServiceInstances(DomainName service)

Parameters

Type	Name	Description
DomainName	service	The service name to query. Typically of the form "_service._tcp".

Remarks

When an answer is received the ServiceInstanceDiscovered event is raised.

See Also

ServiceName

QueryServiceInstances(DomainName, String)

Asks instances of the specified service with the subtype to send details.

Declaration

public void QueryServiceInstances(DomainName service, string subtype)

Parameters

Type	Name	Description
DomainName	service	The service name to query. Typically of the form "_service._tcp".
String	subtype	The feature that is needed.

Remarks

When an answer is received the ServiceInstanceDiscovered event is raised.

See Also

ServiceName

QueryUnicastAllServices()

Asks other MDNS services to send their service names; accepts unicast and/or broadcast answers.

Declaration

public void QueryUnicastAllServices()

Remarks

When an answer is received the ServiceDiscovered event is raised.

QueryUnicastServiceInstances(DomainName)

Asks instances of the specified service to send details. accepts unicast and/or broadcast answers.

Declaration

public void QueryUnicastServiceInstances(DomainName service)

Parameters

Type	Name	Description
DomainName	service	The service name to query. Typically of the form "_service._tcp".

Remarks

When an answer is received the ServiceInstanceDiscovered event is raised.

See Also

ServiceName

Unadvertise()

Sends a goodbye message for each anounced service.

Declaration

public void Unadvertise()

Unadvertise(ServiceProfile)

Sends a goodbye message for the provided profile and removes its pointer from the name sever.

Declaration

public void Unadvertise(ServiceProfile profile)

Parameters

Type	Name	Description
ServiceProfile	profile	The profile to send a goodbye message for.

Events

ServiceDiscovered

Raised when a DNS-SD response is received.

Declaration

public event EventHandler<DomainName> ServiceDiscovered

Event Type

Type	Description
EventHandler<DomainName>	Contains the service name.

Remarks

ServiceDiscovery passively monitors the network for any answers to a DNS-SD query. When an anwser is received this event is raised.

Use QueryAllServices() to initiate a DNS-SD question.

ServiceInstanceDiscovered

Raised when a servive instance is discovered.

Declaration

public event EventHandler<ServiceInstanceDiscoveryEventArgs> ServiceInstanceDiscovered

Event Type

Type	Description
EventHandler<ServiceInstanceDiscoveryEventArgs>	Contains the service instance name.

Remarks

ServiceDiscovery passively monitors the network for any answers. When an answer containing a PTR to a service instance is received this event is raised.

ServiceInstanceShutdown

Raised when a servive instance is shutting down.

Declaration

public event EventHandler<ServiceInstanceShutdownEventArgs> ServiceInstanceShutdown

Event Type

Type	Description
EventHandler<ServiceInstanceShutdownEventArgs>	Contains the service instance name.

Remarks

ServiceDiscovery passively monitors the network for any answers. When an answer containing a PTR to a service instance with a TTL of zero is received this event is raised.

Implements

System.IDisposable

See Also

RFC 6763 DNS-Based Service Discovery