Struct MultiNetworkDriver

The MultiNetworkDriver structure is a way to manipulate multiple instances of NetworkDriver at the same time. This abstraction is meant to make it easy to work with servers that must accept different connection types (e.g. both UDP and WebSocket connections). This is useful for cross-play support across different platforms.

Inherited Members

ValueType.Equals(Object)

ValueType.GetHashCode()

ValueType.ToString()

Object.Equals(Object, Object)

Object.ReferenceEquals(Object, Object)

Object.GetType()

Namespace: Unity.Networking.Transport

Syntax

public struct MultiNetworkDriver : IDisposable

Examples

This code below shows how to create a MultiNetworkDriver that accepts both UDP and WebSocket connections.

    var udpDriver = NetworkDriver.Create(new UDPNetworkInterface());
    udpDriver.Bind(NetworkEndpoint.AnyIpv4.WithPort(7777)); // UDP port
    udpDriver.Listen();

    var wsDriver = NetworkDriver.Create(new WebSocketNetworkInterface());
    wsDriver.Bind(NetworkEndpoint.AnyIpv4.WithPort(7777)); // TCP port
    wsDriver.Listen();

    var multiDriver = MultiNetworkDriver.Create();
    multiDriver.AddDriver(udpDriver);
    multiDriver.AddDriver(wsDriver);

The created MultiNetworkDriver can then be used as one would use a NetworkDriver since they share most of the same APIs.

Fields

MaxDriverCount

The maximum number of drivers that can be added to a MultiNetworkDriver.

Declaration

public const int MaxDriverCount = 4

Field Value

Type	Description
Int32	Number of drivers.

Properties

DriverCount

Number of drivers that have been added.

Declaration

public int DriverCount { readonly get; }

Property Value

Type	Description
Int32	Number of drivers.

IsCreated

Whether the MultiNetworkDriver has been created.

Declaration

public readonly bool IsCreated { get; }

Property Value

Type	Description
Boolean	True if created, false otherwise.

Methods

AbortSend(DataStreamWriter)

Aborts a send started with BeginSend(NetworkPipeline, NetworkConnection, out DataStreamWriter, Int32).

Declaration

public void AbortSend(DataStreamWriter writer)

Parameters

Type	Name	Description
DataStreamWriter	writer	DataStreamWriter to cancel.

Exceptions

Type	Condition
ArgumentException	If writer was not obtained by a prior call to BeginSend(NetworkConnection, out DataStreamWriter, Int32).

Accept()

Accept any new incoming connections. Connections must be accepted before data can be sent on them. It's also the only way to obtain the NetworkConnection value for new connections on servers.

Declaration

public NetworkConnection Accept()

Returns

Type	Description
NetworkConnection	New connection if any, otherwise a default-value object.

AddDriver(NetworkDriver)

Add a NetworkDriver instance to the MultiNetworkDriver. This driver instance must not already have any active connections, and must have the same number of pipelines as previously added instances. Drivers that are intended to take on a server role must also already be in the listening state.

Declaration

public int AddDriver(NetworkDriver driver)

Parameters

Type	Name	Description
NetworkDriver	driver	NetworkDriver instance to add.

Returns

Type	Description
Int32	An ID identifying the NetworkDriver inside the MultiNetworkDriver. This ID can be used to retrieve the driver using the GetDriver(Int32) method.

Remarks

The MultiNetworkDriver takes ownership of the NetworkDriver. While it is possible to keep operating on the NetworkDriver once it's been added, this is not recommended (at least for the operations that are already covered by the MultiNetworkDriver API).

Exceptions

Type	Condition
InvalidOperationException	If the MultiNetworkDriver is at capacity (see MaxDriverCount).
ArgumentException	If the driver already has active connections, or if it doesn't have as many pipelines as previously added drivers. Note that this exception is only thrown when safety checks are enabled (i.e. in the editor), otherwise the driver will be added anyway.

BeginSend(NetworkConnection, out DataStreamWriter, Int32)

Begin sending data on the given connection (default pipeline).

Declaration

public int BeginSend(NetworkConnection connection, out DataStreamWriter writer, int requiredPayloadSize = 0)

Parameters

Type	Name	Description
NetworkConnection	connection	Connection to send the data to.
DataStreamWriter	writer	DataStreamWriter the data can be written to.
Int32	requiredPayloadSize	Size that the returned DataStreamWriter must support. The method will return an error if that payload size is not supported by the pipeline. Defaults to 0, which means the DataStreamWriter will be as large as it can be.

Returns

Type	Description
Int32	0 on success, a negative value on error.

Exceptions

Type	Condition
ArgumentException	If connection was not obtained by a prior call to this MultiNetworkDriver.

BeginSend(NetworkPipeline, NetworkConnection, out DataStreamWriter, Int32)

Begin sending data on the given connection and pipeline.

Declaration

public int BeginSend(NetworkPipeline pipe, NetworkConnection connection, out DataStreamWriter writer, int requiredPayloadSize = 0)

Parameters

Type	Name	Description
NetworkPipeline	pipe	Pipeline to send the data on.
NetworkConnection	connection	Connection to send the data to.
DataStreamWriter	writer	DataStreamWriter the data can be written to.
Int32	requiredPayloadSize	Size that the returned DataStreamWriter must support. The method will return an error if that payload size is not supported by the pipeline. Defaults to 0, which means the DataStreamWriter will be as large as it can be.

Returns

Type	Description
Int32	0 on success, a negative error code on error.

Exceptions

Type	Condition
ArgumentException	If connection was not obtained by a prior call to this MultiNetworkDriver.

Connect(Int32, NetworkEndpoint)

Establish a new connection to the given endpoint. Note that this only starts establishing the new connection. From there it will either succeeds (a Connect event will pop on the connection) or fail (a Disconnect event will pop on the connection) at a later time.

Declaration

public NetworkConnection Connect(int driverId, NetworkEndpoint endpoint)

Parameters

Type	Name	Description
Int32	driverId	ID of the driver to connect, as obtained with AddDriver(NetworkDriver).
NetworkEndpoint	endpoint

Returns

Type	Description
NetworkConnection	New connection object, or a default-valued object on failure.

Remarks

Establishing a new connection normally requires the driver to be bound (e.g. with the Bind(NetworkEndpoint) method), but if that's not the case when calling this method, the driver will be implicitly bound to the appropriate wildcard address. This is a behavior similar to BSD sockets, where calling connect automatically binds the socket to an ephemeral port.

Create()

Create a new MultiNetworkDriver instance.

Declaration

public static MultiNetworkDriver Create()

Returns

Type	Description
MultiNetworkDriver	The new MultiNetworkDriver instance.

CreatePipeline(Type[])

Create a new pipeline from stage types.

Declaration

public NetworkPipeline CreatePipeline(params Type[] stages)

Parameters

Type	Name	Description
Type[]	stages	Array of stages the pipeline should contain.

Returns

Type	Description
NetworkPipeline

Remarks

The order of the different stages is important, as that is the order in which the stages will process a packet when sending messages (the reverse order is used when processing received packets).

Exceptions

Type	Condition
InvalidOperationException	If called after the driver has established connections or before it is created. Note this is only thrown if safety checks are enabled (i.e. in the editor).

CreatePipeline(NativeArray<NetworkPipelineStageId>)

Create a new pipeline from stage types.

Declaration

public NetworkPipeline CreatePipeline(NativeArray<NetworkPipelineStageId> stages)

Parameters

Type	Name	Description
NativeArray<NetworkPipelineStageId>	stages

Returns

Type	Description
NetworkPipeline

Remarks

The order of the different stages is important, as that is the order in which the stages will process a packet when sending messages (the reverse order is used when processing received packets).

Exceptions

Type	Condition
InvalidOperationException	If called after the driver has established connections or before it is created. Note this is only thrown if safety checks are enabled (i.e. in the editor).

Disconnect(NetworkConnection)

Close a connection. Note that to properly notify a peer of this disconnection, it is required to schedule at least one update with ScheduleUpdate(JobHandle) and complete it. Failing to do could leave the remote peer unaware that the connection has been closed (however it will time out on its own after a while).

Declaration

public void Disconnect(NetworkConnection connection)

Parameters

Type	Name	Description
NetworkConnection	connection	Connection to close.

Exceptions

Type	Condition
ArgumentException	If connection was not obtained by a prior call to this MultiNetworkDriver.

Dispose()

Declaration

public void Dispose()

Implements

IDisposable.Dispose()

EndSend(DataStreamWriter)

Enqueue a send operation for the data in the given DataStreamWriter, which must have been obtained by a prior call to BeginSend(NetworkPipeline, NetworkConnection, out DataStreamWriter, Int32).

Declaration

public int EndSend(DataStreamWriter writer)

Parameters

Type	Name	Description
DataStreamWriter	writer	DataStreamWriter to send.

Returns

Type	Description
Int32	The number of bytes to be sent on success, a negative value on error.

Remarks

This method doesn't actually send anything on the wire. It simply enqueues the send operation, which will be performed in the next ScheduleFlushSend(JobHandle) or ScheduleUpdate(JobHandle) job.

Exceptions

Type	Condition
ArgumentException	If writer was not obtained by a prior call to BeginSend(NetworkConnection, out DataStreamWriter, Int32).

GetConnectionState(NetworkConnection)

Get the current state of the given connection.

Declaration

public NetworkConnection.State GetConnectionState(NetworkConnection connection)

Parameters

Type	Name	Description
NetworkConnection	connection	Connection to get the state of.

Returns

Type	Description
NetworkConnection.State	State of the connection.

Exceptions

Type	Condition
ArgumentException	If connection was not obtained by a prior call to this MultiNetworkDriver.

GetDriver(Int32)

Get a NetworkDriver previously added with AddDriver(NetworkDriver).

Declaration

public NetworkDriver GetDriver(int id)

Parameters

Type	Name	Description
Int32	id	ID of the driver as returned by AddDriver(NetworkDriver).

Returns

Type	Description
NetworkDriver	The NetworkDriver referred to by id.

Remarks

This method is provided as an escape hatch for use cases not covered by the MultiNetworkDriver API. Using this method to perform operations on a driver that could be performed through MultiNetworkDriver is likely to result in errors or corrupted state.

Exceptions

Type	Condition
ArgumentException	If id does not refer to a driver that's part of the MultiNetworkDriver.

GetDriverForConnection(NetworkConnection)

Get the NetworkDriver associated with the given connection. The connection must have been obtained from the MultiNetworkDriver before.

Declaration

public NetworkDriver GetDriverForConnection(NetworkConnection connection)

Parameters

Type	Name	Description
NetworkConnection	connection	Connection to get the driver of.

Returns

Type	Description
NetworkDriver	The NetworkDriver associated to connection.

Exceptions

Type	Condition
ArgumentException	If connection was not obtained by a prior call to this MultiNetworkDriver.

GetRemoteEndpoint(NetworkConnection)

Get the remote endpoint of a connection (the endpoint used to reach the remote peer on the connection).

Declaration

public NetworkEndpoint GetRemoteEndpoint(NetworkConnection connection)

Parameters

Type	Name	Description
NetworkConnection	connection	Connection to get the endpoint of.

Returns

Type	Description
NetworkEndpoint	The remote endpoint of the connection.

Remarks

The returned value should not be assumed to be constant for a given connection, as it is possible for remote peers to change address during the course of a session (e.g. if a mobile client changes IP address because they're hopping between cell towers).

Exceptions

Type	Condition
ArgumentException	If connection was not obtained by a prior call to this MultiNetworkDriver.

PopEvent(out NetworkConnection, out DataStreamReader)

Pops the next event from the event queue, Empty will be returned if there are no more events to pop.

Declaration

public NetworkEvent.Type PopEvent(out NetworkConnection connection, out DataStreamReader reader)

Parameters

Type	Name	Description
NetworkConnection	connection	Connection on which the event occured.
DataStreamReader	reader	DataStreamReader from which the event data (e.g. payload) can be read from.

Returns

Type	Description
NetworkEvent.Type	The type of the event popped.

Remarks

The reader obtained from this method will contain different things for different event types. For Data, it contains the actual received payload. For Disconnect, it contains a single byte identifying the reason for the disconnection (see DisconnectReason). For other event types, it contains nothing.

PopEvent(out NetworkConnection, out DataStreamReader, out NetworkPipeline)

Pops the next event from the event queue, Empty will be returned if there are no more events to pop.

Declaration

public NetworkEvent.Type PopEvent(out NetworkConnection connection, out DataStreamReader reader, out NetworkPipeline pipe)

Parameters

Type	Name	Description
NetworkConnection	connection	Connection on which the event occured.
DataStreamReader	reader	DataStreamReader from which the event data (e.g. payload) can be read from.
NetworkPipeline	pipe	Pipeline on which the data event was received.

Returns

Type	Description
NetworkEvent.Type	The type of the event popped.

Remarks

The reader obtained from this method will contain different things for different event types. For Data, it contains the actual received payload. For Disconnect, it contains a single byte identifying the reason for the disconnection (see DisconnectReason). For other event types, it contains nothing.

PopEventForConnection(NetworkConnection, out DataStreamReader)

Pops the next event from the event queue for the given connection, Empty will be returned if there are no more events.

Declaration

public NetworkEvent.Type PopEventForConnection(NetworkConnection connection, out DataStreamReader reader)

Parameters

Type	Name	Description
NetworkConnection	connection	Connection for which to pop the event.
DataStreamReader	reader	DataStreamReader from which the event data (e.g. payload) can be read from.

Returns

Type	Description
NetworkEvent.Type	The type of the event popped.

Remarks

The reader obtained from this method will contain different things for different event types. For Data, it contains the actual received payload. For Disconnect, it contains a single byte identifying the reason for the disconnection (see DisconnectReason). For other event types, it contains nothing.

Exceptions

Type	Condition
ArgumentException	If connection was not obtained by a prior call to this MultiNetworkDriver.

PopEventForConnection(NetworkConnection, out DataStreamReader, out NetworkPipeline)

Pops the next event from the event queue for the given connection, Empty will be returned if there are no more events.

Declaration

public NetworkEvent.Type PopEventForConnection(NetworkConnection connection, out DataStreamReader reader, out NetworkPipeline pipe)

Parameters

Type	Name	Description
NetworkConnection	connection	Connection for which to pop the event.
DataStreamReader	reader	DataStreamReader from which the event data (e.g. payload) can be read from.
NetworkPipeline	pipe	Pipeline on which the data event was received.

Returns

Type	Description
NetworkEvent.Type	The type of the event popped.

Remarks

The reader obtained from this method will contain different things for different event types. For Data, it contains the actual received payload. For Disconnect, it contains a single byte identifying the reason for the disconnection (see DisconnectReason). For other event types, it contains nothing.

Exceptions

Type	Condition
ArgumentException	If connection was not obtained by a prior call to this MultiNetworkDriver.

RegisterPipelineStage<T>(T)

Register a custom pipeline stage.

Declaration

public void RegisterPipelineStage<T>(T stage)
    where T : struct, INetworkPipelineStage

Parameters

Type	Name	Description
T	stage	An instance of the pipeline stage.

Type Parameters

Name	Description
T	Type of the pipeline stage (must be unmanaged).

Remarks

Can only be called before a driver is bound (see Bind(NetworkEndpoint)).

Note that the default pipeline stages (FragmentationPipelineStage, ReliableSequencedPipelineStage, UnreliableSequencedPipelineStage, and SimulatorPipelineStage) don't need to be registered. Registering a pipeline stage is only required for custom ones.

Exceptions

Type	Condition
InvalidOperationException	If the driver is not created or bound. Note that this is only thrown if safety checks are enabled (i.e. in the editor). Otherwise the pipeline is registered anyway (with likely erroneous behavior down the line).

ScheduleFlushSend(JobHandle)

Schedule a send job. This job is basically a subset of the update job (see ScheduleUpdate(JobHandle)) and only takes care of sending packets queued with EndSend(DataStreamWriter). It should be lightweight enough to schedule multiple times per tick to improve latency if there's a significant amount of packets being sent.

Declaration

public JobHandle ScheduleFlushSend(JobHandle dependency = default(JobHandle))

Parameters

Type	Name	Description
JobHandle	dependency	Job to depend on.

Returns

Type	Description
JobHandle	Handle to the send job.

ScheduleUpdate(JobHandle)

Schedule an update job. This job will process incoming packets and check timeouts (queueing up the relevant events to be consumed by PopEvent(out NetworkConnection, out DataStreamReader) and Accept()) and will send any packets queued with EndSend(DataStreamWriter). This job should generally be scheduled once per tick.

Declaration

public JobHandle ScheduleUpdate(JobHandle dependency = default(JobHandle))

Parameters

Type	Name	Description
JobHandle	dependency	Job to depend on.

Returns

Type	Description
JobHandle	Handle to the update job.

ToConcurrent()

Create a NetworkDriver.Concurrent copy of the NetworkDriver.

Declaration

public MultiNetworkDriver.Concurrent ToConcurrent()

Returns

Type	Description
MultiNetworkDriver.Concurrent	A NetworkDriver.Concurrent instance for the driver.