1 /*
2 * Copyright (C) 2018, Thomas Wolf <thomas.wolf@paranor.ch>
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43 package org.eclipse.jgit.internal.transport.sshd.auth;
44
45 import java.io.Closeable;
46
47 /**
48 * An {@code AuthenticationHandler} encapsulates a possibly multi-step
49 * authentication protocol. Intended usage:
50 *
51 * <pre>
52 * setParams(something);
53 * start();
54 * sendToken(getToken());
55 * while (!isDone()) {
56 * setParams(receiveMessageAndExtractParams());
57 * process();
58 * Object t = getToken();
59 * if (t != null) {
60 * sendToken(t);
61 * }
62 * }
63 * </pre>
64 *
65 * An {@code AuthenticationHandler} may be stateful and therefore is a
66 * {@link Closeable}.
67 *
68 * @param <ParameterType>
69 * defining the parameter type for {@link #setParams(Object)}
70 * @param <TokenType>
71 * defining the token type for {@link #getToken()}
72 */
73 public interface AuthenticationHandler<ParameterType, TokenType>
74 extends Closeable {
75
76 /**
77 * Produces the initial authentication token that can be then retrieved via
78 * {@link #getToken()}.
79 *
80 * @throws Exception
81 * if an error occurs
82 */
83 void start() throws Exception;
84
85 /**
86 * Produces the next authentication token, if any.
87 *
88 * @throws Exception
89 * if an error occurs
90 */
91 void process() throws Exception;
92
93 /**
94 * Sets the parameters for the next token generation via {@link #start()} or
95 * {@link #process()}.
96 *
97 * @param input
98 * to set, may be {@code null}
99 */
100 void setParams(ParameterType input);
101
102 /**
103 * Retrieves the last token generated.
104 *
105 * @return the token, or {@code null} if there is none
106 * @throws Exception
107 * if an error occurs
108 */
109 TokenType getToken() throws Exception;
110
111 /**
112 * Tells whether is authentication mechanism is done (successfully or
113 * unsuccessfully).
114 *
115 * @return whether this authentication is done
116 */
117 boolean isDone();
118
119 @Override
120 void close();
121 }