Package org.apache.sshd.common.kex.extension

Class DefaultServerKexExtensionHandler

java.lang.Object

org.apache.sshd.common.util.logging.AbstractLoggingBean

org.apache.sshd.common.kex.extension.DefaultServerKexExtensionHandler

All Implemented Interfaces:

KexExtensionHandler

public class DefaultServerKexExtensionHandler
extends AbstractLoggingBean
implements KexExtensionHandler

A basic default implementation of a server-side KexExtensionHandler handling the ServerSignatureAlgorithms KEX extension.

See Also:

• RFC 8308

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.sshd.common.kex.extension.KexExtensionHandler

KexExtensionHandler.AvailabilityPhase, KexExtensionHandler.KexPhase

Field Summary

Fields

Modifier and Type	Field	Description
static final AttributeRepository.AttributeKey<Boolean>	CLIENT_REQUESTED_EXT_INFO	Session AttributeRepository.AttributeKey storing whether the client requested to get the EXT_INFO message.
static final AttributeRepository.AttributeKey<Boolean>	EXT_INFO_SENT_AT_NEWKEYS	Session AttributeRepository.AttributeKey storing whether the server sent an EXT_INFO message at KexExtensionHandler.KexPhase.NEWKEYS.
static final DefaultServerKexExtensionHandler	INSTANCE	Default singleton instance.

Fields inherited from class org.apache.sshd.common.util.logging.AbstractLoggingBean

log

Constructor Summary

Constructors

Constructor	Description
DefaultServerKexExtensionHandler()

Method Summary

Modifier and Type	Method	Description
void	collectExtensions(Session session, KexExtensionHandler.KexPhase phase, BiConsumer<String,Object> marshaller)	Collects extension info records, handing them off to the given marshaller for writing into an KexExtensions.SSH_MSG_EXT_INFO message.
void	handleKexInitProposal(Session session, boolean initiator, Map<KexProposalOption,String> proposal)	Invoked when a peer is ready to send the KEX options proposal or has received such a proposal.
void	sendKexExtensions(Session session, KexExtensionHandler.KexPhase phase)	Invoked in order to allow the handler to send an SSH_MSG_EXT_INFO message.

Methods inherited from class org.apache.sshd.common.util.logging.AbstractLoggingBean

debug, debug, debug, debug, debug, error, error, error, error, error, getSimplifiedLogger, info, info, warn, warn, warn, warn, warn, warn, warn, warn

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.sshd.common.kex.extension.KexExtensionHandler

handleKexCompressionMessage, handleKexExtensionNegotiation, handleKexExtensionRequest, handleKexExtensionsMessage, isKexExtensionsAvailable

Field Details

INSTANCE

public static final DefaultServerKexExtensionHandler INSTANCE

Default singleton instance.

CLIENT_REQUESTED_EXT_INFO

public static final AttributeRepository.AttributeKey<Boolean> CLIENT_REQUESTED_EXT_INFO

Session AttributeRepository.AttributeKey storing whether the client requested to get the EXT_INFO message. Possible values are:

null

Unknown. We have not yet received the client's KEX proposal. Do not send the message.

Boolean.TRUE

We have received the client's KEX proposal, and the client has requested to get the EXT_INFO message.

Boolean.FALSE

We have received the client's KEX proposal, and the client did not request to get the EXT_INFO message. Do not send the message.

EXT_INFO_SENT_AT_NEWKEYS

public static final AttributeRepository.AttributeKey<Boolean> EXT_INFO_SENT_AT_NEWKEYS

Session AttributeRepository.AttributeKey storing whether the server sent an EXT_INFO message at KexExtensionHandler.KexPhase.NEWKEYS. A server is supposed to send the message at that point only on the very first NEWKEYS message. Possible values are:

null or Boolean.FALSE

The EXT_INFO message at KexExtensionHandler.KexPhase.NEWKEYS was not done yet.

Boolean.TRUE

The EXT_INFO message at KexExtensionHandler.KexPhase.NEWKEYS was done.

Constructor Details

DefaultServerKexExtensionHandler

public DefaultServerKexExtensionHandler()

Method Details

handleKexInitProposal

public void handleKexInitProposal(Session session,
 boolean initiator,
 Map<KexProposalOption,String> proposal)
                           throws Exception

Description copied from interface: KexExtensionHandler

Invoked when a peer is ready to send the KEX options proposal or has received such a proposal. Note: this method is called during the negotiation phase even if isKexExtensionsAvailable returns false for the session.

Specified by:

handleKexInitProposal in interface KexExtensionHandler

Parameters:

session - The Session initiating or receiving the proposal

initiator - true if the proposal is about to be sent, false if this is a proposal received from the peer.

proposal - The proposal contents - Caveat emptor: the proposal is modifiable i.e., the handler can modify it before being sent or before being processed (if incoming)

Throws:

Exception - If failed to handle the request

sendKexExtensions

public void sendKexExtensions(Session session,
 KexExtensionHandler.KexPhase phase)
                       throws Exception

Description copied from interface: KexExtensionHandler

Invoked in order to allow the handler to send an SSH_MSG_EXT_INFO message. Note: this method is called only if isKexExtensionsAvailable returns true for the session.

Specified by:

sendKexExtensions in interface KexExtensionHandler

Parameters:

session - The Session

phase - The phase at which the handler is invoked

Throws:

Exception - If failed to handle the invocation

See Also:

• RFC-8308 - section 2.4

collectExtensions

public void collectExtensions(Session session,
 KexExtensionHandler.KexPhase phase,
 BiConsumer<String,Object> marshaller)

Collects extension info records, handing them off to the given marshaller for writing into an KexExtensions.SSH_MSG_EXT_INFO message.

This default implementation marshals a ServerSignatureAlgorithms extension if the phase is KexExtensionHandler.KexPhase.NEWKEYS.

Parameters:

session - Session to send the KEX extension information for

phase - KexExtensionHandler.KexPhase of the SSH protocol

marshaller - BiConsumer writing the extensions into an SSH message