This class implements a UDP network interface. More...

#include <UdpNetworkInterface.h>

Inherits AzNetworking::INetworkInterface.

Public Member Functions
	UdpNetworkInterface (const AZ::Name &name, IConnectionListener &connectionListener, TrustZone trustZone, UdpReaderThread &readerThread)


AZ::Name	GetName () const override

ProtocolType	GetType () const override

TrustZone	GetTrustZone () const override

uint16_t	GetPort () const override

IConnectionSet &	GetConnectionSet () override

IConnectionListener &	GetConnectionListener () override

bool	Listen (uint16_t port) override

ConnectionId	Connect (const IpAddress &remoteAddress, uint16_t localPort=0) override

void	Update () override
	Updates the INetworkInterface.

bool	SendReliablePacket (ConnectionId connectionId, const IPacket &packet) override

PacketId	SendUnreliablePacket (ConnectionId connectionId, const IPacket &packet) override

bool	WasPacketAcked (ConnectionId connectionId, PacketId packetId) override

bool	StopListening () override

bool	Disconnect (ConnectionId connectionId, DisconnectReason reason) override

void	SetTimeoutMs (AZ::TimeMs timeoutMs) override

AZ::TimeMs	GetTimeoutMs () const override

bool	IsEncrypted () const override

bool	IsOpen () const override

Public Member Functions inherited from AzNetworking::INetworkInterface
	AZ_RTTI (INetworkInterface, "{ECDA6FA2-4AA0-435E-881F-214C4B179A31}")

virtual AZ::Name	GetName () const =0

virtual ProtocolType	GetType () const =0

virtual TrustZone	GetTrustZone () const =0

virtual uint16_t	GetPort () const =0

virtual IConnectionSet &	GetConnectionSet ()=0

virtual IConnectionListener &	GetConnectionListener ()=0

virtual bool	Listen (uint16_t port)=0

virtual ConnectionId	Connect (const IpAddress &remoteAddress, uint16_t localPort=0)=0

virtual void	Update ()=0
	Updates the INetworkInterface.

virtual bool	SendReliablePacket (ConnectionId connectionId, const IPacket &packet)=0

virtual PacketId	SendUnreliablePacket (ConnectionId connectionId, const IPacket &packet)=0

virtual bool	WasPacketAcked (ConnectionId connectionId, PacketId packetId)=0

virtual bool	StopListening ()=0

virtual bool	Disconnect (ConnectionId connectionId, DisconnectReason reason)=0

virtual void	SetTimeoutMs (AZ::TimeMs timeoutMs)=0

virtual AZ::TimeMs	GetTimeoutMs () const =0

const NetworkInterfaceMetrics &	GetMetrics () const

NetworkInterfaceMetrics &	GetMetrics ()

virtual bool	IsEncrypted () const =0

virtual bool	IsOpen () const =0

Friends
class	UdpReliableQueue

class	UdpConnection

Detailed Description

This class implements a UDP network interface.

UdpNetworkInterface is an implementation of AzNetworking::INetworkInterface. Since UDP is a very bare bones protocol, the Open 3D Engine implementation has to provide significantly more than its TCP counterpart (since TCP implements a significant number of reliability features.)

When sent through UDP, a packet can have additional actions performed on it depending on which features are enabled and configured. Each feature listed in this description is in the order a packet will see them on Send.

Packet structure

The general structure of a UDP packet is:

Flags - A bitfield a receiving endpoint can quickly inspect to learn about configuration of a packet
Header - Details the type of packet and other information related to reliability
Payload - The actual serialized content of the packet

For more information, read Networking Packets in the O3DE documentation.

Reliability

UDP packets can be sent reliably or unreliably. Reliably sent packets are registered for tracking first. This causes the reliable packet to be resent if a timeout on the packet is reached. Once the packet is acknowledged, the packet is unregistered.

Fragmentation

If the raw packet size exceeds the configured maximum transmission unit (MTU) then the packet is broken into multiple fragments to avoid fragmentation at the routing level. Fragment reliability is controlled by the cvar net_FragmentsAlwaysReliable. When true, fragments are always sent reliably to ensure the source packet can be reconstructed. This means unreliable packets exceeding MTU will be split into several reliable packets to guarantee delivery but at a cost of extra network processing. (Default) When false, fragments inherit the reliability type of their source packet. This may cause non-reliable packet transmission to fail if packet is fragmented, if even one fragment fails to be delivered due to network conditions.

Optimizing packets to remain under MTU and appropriate usage of reliable packets is recommended before enabling net_FragmentsAlwaysReliable.

Operations that alter the payload generally follow this step so that they can be separately applied to the Fragments in addition to not being applied to both the original and Fragments.

Compression

Compression here refers to content insensitive compression using libraries like LZ4. If enabled, the target payload is run through the compressor and replaces the original payload if it's in fact smaller. To tell if compression is enabled on a given packet, we operate on a bit in the packet's Flags. The Sender writes this bit while the Receiver checks it to see if a packet needs to be decompressed.

O3DE could potentially move from over MTU to under with compression, and the UDP interface doesn't check for this. Detecting a change that would reduce the number of fragmented packets would require pre-emptively compressing payloads to tell if that change happened, which could potentially lead to a lot of unnecessary calls to the compressor.

Encryption

AzNetworking uses the OpenSSL library to implement Datagram Layer Transport Security (DTLS) encryption on UDP traffic. Encryption operates as described in O3DE Networking Encryption on the documentation website. Once both endpoints have completed their handshake, all traffic is expected to be fully encrypted.

Constructor & Destructor Documentation

◆ UdpNetworkInterface()

AzNetworking::UdpNetworkInterface::UdpNetworkInterface	(	const AZ::Name &	name,
		IConnectionListener &	connectionListener,
		TrustZone	trustZone,
		UdpReaderThread &	readerThread
	)

Constructor.

Parameters

name	the name of this network interface instance.
connectionListener	reference to the connection listener responsible for handling all connection events
trustZone	the trust level assigned to this network interface, server to server or client to server
readerThread	pointer to the reader thread to be bound to this network interface

Member Function Documentation

◆ Connect()

ConnectionId AzNetworking::UdpNetworkInterface::Connect	(	const IpAddress &	remoteAddress,
		uint16_t	localPort = `0`
	)

overridevirtual

Opens a new connection to the provided address.

Parameters

remoteAddress	the IpAddress of the remote process to open a connection to
localPort	the local port number to open a socket on to initiate the connection, 0 binds to any available port

Returns: the connectionId of the new connection, or InvalidConnectionId if the operation failed

Implements AzNetworking::INetworkInterface.

◆ Disconnect()

bool AzNetworking::UdpNetworkInterface::Disconnect	(	ConnectionId	connectionId,
		DisconnectReason	reason
	)

overridevirtual

Disconnects the specified connection.

Parameters

connectionId	identifier of the connection to terminate
reason	reason for the disconnect

Returns: boolean true on success

Implements AzNetworking::INetworkInterface.

◆ GetConnectionListener()

IConnectionListener & AzNetworking::UdpNetworkInterface::GetConnectionListener ( )

overridevirtual

Returns a reference to the connection listener for this network interface.

Returns: reference to the connection listener for this network interface

Implements AzNetworking::INetworkInterface.

◆ GetConnectionSet()

IConnectionSet & AzNetworking::UdpNetworkInterface::GetConnectionSet ( )

overridevirtual

Returns the connection set for this network interface.

Returns: the connection set for this network interface

Implements AzNetworking::INetworkInterface.

◆ GetName()

AZ::Name AzNetworking::UdpNetworkInterface::GetName ( ) const

overridevirtual

INetworkInterface interface.

Implements AzNetworking::INetworkInterface.

◆ GetPort()

uint16_t AzNetworking::UdpNetworkInterface::GetPort ( ) const

overridevirtual

Returns the port number this network interface is bound to.

Returns: the port number this network interface is bound to

Implements AzNetworking::INetworkInterface.

◆ GetTimeoutMs()

AZ::TimeMs AzNetworking::UdpNetworkInterface::GetTimeoutMs ( ) const

overridevirtual

Retrieves the timeout time in milliseconds for this network interface, 0 ms means timeouts are disabled.

Returns: the timeout time in milliseconds for this network interface, 0 ms means timeouts are disabled

Implements AzNetworking::INetworkInterface.

◆ GetTrustZone()

TrustZone AzNetworking::UdpNetworkInterface::GetTrustZone ( ) const

overridevirtual

Retrieves the trust zone for this network interface instance.

Returns: the trust zone for this network interface instance

Implements AzNetworking::INetworkInterface.

◆ GetType()

ProtocolType AzNetworking::UdpNetworkInterface::GetType ( ) const

overridevirtual

Retrieves the type of this network interface instance.

Returns: the type of this network interface instance

Implements AzNetworking::INetworkInterface.

◆ IsEncrypted()

bool AzNetworking::UdpNetworkInterface::IsEncrypted ( ) const

overridevirtual

Returns true if communications on this network interface are encrypted, false if not.

Returns: boolean true if communciations are encrypted, false if not

Implements AzNetworking::INetworkInterface.

◆ IsOpen()

bool AzNetworking::UdpNetworkInterface::IsOpen ( ) const

overridevirtual

Returns true if this connection instance is in an open state, and is capable of actively sending and receiving packets.

Returns: boolean true if this connection instance is in an open state

Implements AzNetworking::INetworkInterface.

◆ Listen()

bool AzNetworking::UdpNetworkInterface::Listen ( uint16_t port )

overridevirtual

Opens the network interface to allow it to accept new incoming connections.

Parameters

port	the listen port number this network interface will potentially bind to, 0 if it's a don't care

Returns: boolean true if the operation was successful, false if it failed

Implements AzNetworking::INetworkInterface.

◆ SendReliablePacket()

bool AzNetworking::UdpNetworkInterface::SendReliablePacket	(	ConnectionId	connectionId,
		const IPacket &	packet
	)

overridevirtual

A helper function that transmits a packet on this connection reliably. Note that a packetId is not returned here, since retransmits may cause the packetId to change

Parameters

connectionId	identifier of the connection to send to
packet	packet to transmit

Returns: boolean true if the packet was transmitted (not an indication of delivery)

Implements AzNetworking::INetworkInterface.

◆ SendUnreliablePacket()

PacketId AzNetworking::UdpNetworkInterface::SendUnreliablePacket	(	ConnectionId	connectionId,
		const IPacket &	packet
	)

overridevirtual

A helper function that transmits a packet on this connection unreliably.

Parameters

connectionId	identifier of the connection to send to
packet	packet to transmit

Returns: the unreliable packet identifier of the transmitted packet

Implements AzNetworking::INetworkInterface.

◆ SetTimeoutMs()

void AzNetworking::UdpNetworkInterface::SetTimeoutMs ( AZ::TimeMs timeoutMs )

overridevirtual

Sets the timeout time in milliseconds, 0 ms means timeouts are disabled.

Parameters

timeoutMs the number of milliseconds with no traffic before we timeout and close a connection

Implements AzNetworking::INetworkInterface.

◆ StopListening()

bool AzNetworking::UdpNetworkInterface::StopListening ( )

overridevirtual

Closes the network interface to stop accepting new incoming connections.

Returns: boolean true if the operation was successful, false if it failed

Implements AzNetworking::INetworkInterface.

◆ Update()

void AzNetworking::UdpNetworkInterface::Update ( )

overridevirtual

Updates the INetworkInterface.

Implements AzNetworking::INetworkInterface.

◆ WasPacketAcked()

bool AzNetworking::UdpNetworkInterface::WasPacketAcked	(	ConnectionId	connectionId,
		PacketId	packetId
	)

overridevirtual

Returns true if the given packet id was confirmed acknowledged by the remote endpoint, false otherwise.

Parameters

connectionId	identifier of the connection to send to
packetId	the packet id of the packet to confirm acknowledgment of

Returns: boolean true if the packet is confirmed acknowledged, false if the packet number is out of range, lost, or still pending acknowledgment

Implements AzNetworking::INetworkInterface.

The documentation for this class was generated from the following file:

Code/Framework/AzNetworking/AzNetworking/UdpTransport/UdpNetworkInterface.h

Public Member Functions

Friends

Detailed Description

Packet structure

Reliability

Fragmentation

Compression

Encryption

Constructor & Destructor Documentation

◆ UdpNetworkInterface()

Member Function Documentation

◆ Connect()

◆ Disconnect()

◆ GetConnectionListener()

◆ GetConnectionSet()

◆ GetName()

◆ GetPort()

◆ GetTimeoutMs()

◆ GetTrustZone()

◆ GetType()

◆ IsEncrypted()

◆ IsOpen()

◆ Listen()

◆ SendReliablePacket()

◆ SendUnreliablePacket()

◆ SetTimeoutMs()

◆ StopListening()

◆ Update()

◆ WasPacketAcked()