Class IceResponder

java.lang.Object

com.hypixel.hytale.server.core.io.ice.IceResponder

public final class IceResponder
extends Object

The controlled half of ICE, running on the socket that carries QUIC.

Answers connectivity checks from joiners and sends its own back along the same path, which is what opens this host's NAT. It never orders pairs or nominates: the joiner is the controlling agent because it owns the socket the handshake runs over.

See Also:

• RFC 8445

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	IceResponder.DatagramSender	Sends a datagram on the listener's socket.

Field Summary

Fields

Modifier and Type	Field	Description
static final Duration	CHECK_INTERVAL	Spacing between outbound checks, matching the client's Ta.

Constructor Summary

Constructors

Constructor	Description
IceResponder(IceResponder.DatagramSender sender)

Method Summary

Modifier and Type	Method	Description
void	addRemoteCandidates(String localUfrag, List<InetSocketAddress> candidates)	Adds addresses to probe for an existing session, which is how a trickled candidate reaches the prober after the session was registered.
boolean	addSession(IceCredentials local, IceCredentials remote)	Registers a peer this host expects to hear from.
boolean	addSession(IceCredentials local, IceCredentials remote, List<InetSocketAddress> remoteCandidates)	Registers a peer and the addresses to probe.
void	clear()	Drops every session, for when the world stops accepting remote joins.
void	handleDatagram(SocketAddress source, ByteBuffer datagram)	Handles one STUN datagram from the listener's reader thread.
boolean	isValidated(InetSocketAddress address)	Whether a peer address has passed an authenticated connectivity check.
void	removeSession(String localUfrag)	Drops a peer's registration.
int	sessionCount()
void	tick()	Sends any outbound checks that are due.

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

CHECK_INTERVAL

public static final Duration CHECK_INTERVAL

Spacing between outbound checks, matching the client's Ta. Pacing keeps a burst of probes from looking like a port scan to the NAT in front of this host.

Constructor Details

IceResponder

public IceResponder(@Nonnull
 IceResponder.DatagramSender sender)

Method Details

addSession

public boolean addSession(@Nonnull
 IceCredentials local,
 @Nonnull
 IceCredentials remote)

Registers a peer this host expects to hear from.

Returns:

false when the peer's credentials are malformed or the session limit is reached

addSession

public boolean addSession(@Nonnull
 IceCredentials local,
 @Nonnull
 IceCredentials remote,
 @Nonnull
 List<InetSocketAddress> remoteCandidates)

Registers a peer and the addresses to probe.

Parameters:

remoteCandidates - addresses the joiner offered, screened by the caller

addRemoteCandidates

public void addRemoteCandidates(@Nonnull
 String localUfrag,
 @Nonnull
 List<InetSocketAddress> candidates)

Adds addresses to probe for an existing session, which is how a trickled candidate reaches the prober after the session was registered.

removeSession

public void removeSession(@Nonnull
 String localUfrag)

Drops a peer's registration.

Always removes. This is the host's only way to revoke a peer it has rejected, so it must not be conditional on what the peer has done. An ordinary signaling close does not reach here: the host leaves that session to the idle timeout, because the joiner closes signaling before its connection exists and then re-proves the path with consent checks.

clear

public void clear()

Drops every session, for when the world stops accepting remote joins.

sessionCount

public int sessionCount()

isValidated

public boolean isValidated(@Nonnull
 InetSocketAddress address)

Whether a peer address has passed an authenticated connectivity check. The QUIC layer uses this to tell a negotiated peer from an unsolicited one.

handleDatagram

public void handleDatagram(@Nonnull
 SocketAddress source,
 @Nonnull
 ByteBuffer datagram)

Handles one STUN datagram from the listener's reader thread.

Must not block. The reader is the only thread draining the socket, so anything slow here stalls inbound traffic for every connection on this listener.

tick

public void tick()

Sends any outbound checks that are due.

Runs on a scheduler, not the listener's reader thread: that thread is the only one draining the socket, so anything sending from it stalls inbound traffic for every connection.