| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| package org.apache.sshd.common.session; |
| |
| import java.io.IOException; |
| import java.util.Map; |
| |
| import org.apache.sshd.common.Service; |
| import org.apache.sshd.common.kex.KexProposalOption; |
| import org.apache.sshd.common.session.helpers.TimeoutIndicator; |
| import org.apache.sshd.common.util.buffer.Buffer; |
| import org.apache.sshd.core.CoreModuleProperties; |
| |
| /** |
| * Invoked when the internal session code decides it should disconnect a session due to some consideration. Usually |
| * allows intervening in the decision and even canceling it. |
| * |
| * @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a> |
| */ |
| public interface SessionDisconnectHandler { |
| /** |
| * Invoked when an internal timeout has expired (e.g., authentication, idle). |
| * |
| * @param session The session whose timeout has expired |
| * @param timeoutStatus The expired timeout |
| * @return {@code true} if expired timeout should be reset (i.e., no disconnect). If {@code false} |
| * then session will disconnect due to the expired timeout |
| * @throws IOException If failed to handle the event |
| */ |
| default boolean handleTimeoutDisconnectReason( |
| Session session, TimeoutIndicator timeoutStatus) |
| throws IOException { |
| return false; |
| } |
| |
| /** |
| * Called to inform that the maximum allowed concurrent sessions threshold has been exceeded. <B>Note:</B> when |
| * handler is invoked the session is not yet marked as having been authenticated, nor has the authentication success |
| * been acknowledged to the peer. |
| * |
| * @param session The session that caused the excess |
| * @param service The {@link Service} instance through which the request was received |
| * @param username The authenticated username that is associated with the session. |
| * @param currentSessionCount The current sessions count |
| * @param maxSessionCount The maximum allowed sessions count |
| * @return {@code true} if accept the exceeding session regardless of the threshold. If |
| * {@code false} then exceeding session will be disconnected |
| * @throws IOException If failed to handle the event, <B>Note:</B> choosing to ignore this disconnect reason |
| * does not reset the current concurrent sessions counter in any way - i.e., the handler |
| * will be re-invoked every time the threshold is exceeded. |
| * @see CoreModuleProperties#MAX_CONCURRENT_SESSIONS |
| */ |
| default boolean handleSessionsCountDisconnectReason( |
| Session session, Service service, String username, int currentSessionCount, int maxSessionCount) |
| throws IOException { |
| return false; |
| } |
| |
| /** |
| * Invoked when a request has been made related to an unknown SSH service as described in |
| * <A HREF="https://tools.ietf.org/html/rfc4253#section-10">RFC 4253 - section 10</A>. |
| * |
| * @param session The session through which the command was received |
| * @param cmd The service related command |
| * @param serviceName The service name |
| * @param buffer Any extra data received in the packet containing the request |
| * @return {@code true} if disregard the request (e.g., the handler handled it) |
| * @throws IOException If failed to handle the request |
| */ |
| default boolean handleUnsupportedServiceDisconnectReason( |
| Session session, int cmd, String serviceName, Buffer buffer) |
| throws IOException { |
| return false; |
| } |
| |
| /** |
| * Invoked if the number of authentication attempts exceeded the maximum allowed |
| * |
| * @param session The session being authenticated |
| * @param service The {@link Service} instance through which the request was received |
| * @param serviceName The authentication service name |
| * @param method The authentication method name |
| * @param user The authentication username |
| * @param currentAuthCount The authentication attempt count |
| * @param maxAuthCount The maximum allowed attempts |
| * @return {@code true} if OK to ignore the exceeded attempt count and allow more attempts. |
| * <B>Note:</B> choosing to ignore this disconnect reason does not reset the current count |
| * - i.e., it will be re-invoked on the next attempt. |
| * @throws IOException If failed to handle the event |
| */ |
| default boolean handleAuthCountDisconnectReason( |
| Session session, Service service, String serviceName, String method, String user, int currentAuthCount, |
| int maxAuthCount) |
| throws IOException { |
| return false; |
| } |
| |
| /** |
| * Invoked if the authentication parameters changed in mid-authentication process. |
| * |
| * @param session The session being authenticated |
| * @param service The {@link Service} instance through which the request was received |
| * @param authUser The original username being authenticated |
| * @param username The requested username |
| * @param authService The original authentication service name |
| * @param serviceName The requested service name |
| * @return {@code true} if OK to ignore the change |
| * @throws IOException If failed to handle the event |
| */ |
| default boolean handleAuthParamsDisconnectReason( |
| Session session, Service service, String authUser, String username, String authService, String serviceName) |
| throws IOException { |
| return false; |
| } |
| |
| /** |
| * Invoked if after KEX negotiation parameters resolved one of the options violates some internal constraint (e.g., |
| * cannot negotiate a value, or <A HREF="https://tools.ietf.org/html/rfc8308#section-2.2">RFC 8308 - section |
| * 2.2</A>). |
| * |
| * @param session The session where the violation occurred |
| * @param c2sOptions The client options |
| * @param s2cOptions The server options |
| * @param negotiatedGuess The negotiated KEX options |
| * @param option The violating {@link KexProposalOption} |
| * @return {@code true} if disregard the violation - if {@code false} then session will disconnect |
| * @throws IOException if attempted to exchange some packets to fix the situation |
| */ |
| default boolean handleKexDisconnectReason( |
| Session session, Map<KexProposalOption, String> c2sOptions, Map<KexProposalOption, String> s2cOptions, |
| Map<KexProposalOption, String> negotiatedGuess, KexProposalOption option) |
| throws IOException { |
| if (KexProposalOption.S2CLANG.equals(option) || KexProposalOption.C2SLANG.equals(option)) { |
| return true; // OK if cannot agree on a language |
| } |
| |
| return false; |
| } |
| } |
