fb34aab6ace8ebf9f568baf3a5b4e3eaddb56edc
[strongswan.git] / src / charon / sa / task_manager.h
1 /**
2 * @file task_manager.h
3 *
4 * @brief Interface of task_manager_t.
5 *
6 */
7
8 /*
9 * Copyright (C) 2006 Martin Willi
10 * Hochschule fuer Technik Rapperswil
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License as published by the
14 * Free Software Foundation; either version 2 of the License, or (at your
15 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
19 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
20 * for more details.
21 */
22
23 #ifndef TASK_MANAGER_H_
24 #define TASK_MANAGER_H_
25
26 typedef struct task_manager_t task_manager_t;
27
28 #include <library.h>
29 #include <encoding/message.h>
30 #include <sa/ike_sa.h>
31 #include <sa/tasks/task.h>
32
33 /**
34 * First retransmit timeout in milliseconds.
35 *
36 * @ingroup sa
37 */
38 #define RETRANSMIT_TIMEOUT 4000
39
40 /**
41 * Base which is raised to the power of the retransmission try.
42 *
43 * @ingroup sa
44 */
45 #define RETRANSMIT_BASE 1.8
46
47 /**
48 * Number of retransmits done before giving up.
49 *
50 * @ingroup sa
51 */
52 #define RETRANSMIT_TRIES 5
53
54
55 /**
56 * @brief The task manager, juggles task and handles message exchanges.
57 *
58 * On incoming requests, the task manager creates new tasks on demand and
59 * juggles the request through all available tasks. Each task inspects the
60 * request and adds payloads as necessary to the response.
61 * On outgoing requests, the task manager delivers the request through the tasks
62 * to build it, the response gets processed by each task to complete.
63 * The task manager has an internal Queue to store task which should get
64 * completed.
65 * For the initial IKE_SA setup, several tasks are queued: One for the
66 * unauthenticated IKE_SA setup, one for authentication, one for CHILD_SA setup
67 * and maybe one for virtual IP assignement.
68 * The task manager is also responsible for retransmission. It uses a backoff
69 * algorithm. The timeout is calculated using
70 * RETRANSMIT_TIMEOUT * (RETRANSMIT_BASE ** try).
71 * When try reaches RETRANSMIT_TRIES, retransmission is given up.
72 *
73 * Using an initial TIMEOUT of 4s, a BASE of 1.8, and 5 TRIES gives us:
74 * @verbatim
75 | relative | absolute
76 ---------------------------------------------------------
77 4s * (1.8 ** 0) = 4s 4s
78 4s * (1.8 ** 1) = 7s 11s
79 4s * (1.8 ** 2) = 13s 24s
80 4s * (1.8 ** 3) = 23s 47s
81 4s * (1.8 ** 4) = 42s 89s
82 4s * (1.8 ** 5) = 76s 165s
83
84 @endberbatim
85 * The peer is considered dead after 2min 45s when no reply comes in.
86 *
87 * @b Constructors:
88 * - task_manager_create()
89 *
90 * @ingroup sa
91 */
92 struct task_manager_t {
93
94 /**
95 * @brief Process an incoming message.
96 *
97 * @param this calling object
98 * @param message message to add payloads to
99 * @return
100 * - DESTROY_ME if IKE_SA must be closed
101 * - SUCCESS otherwise
102 */
103 status_t (*process_message) (task_manager_t *this, message_t *message);
104
105 /**
106 * @brief Initiate an exchange with the currently queued tasks.
107 *
108 * @param this calling object
109 */
110 status_t (*initiate) (task_manager_t *this);
111
112 /**
113 * @brief Queue a task in the manager.
114 *
115 * @param this calling object
116 * @param task task to queue
117 */
118 void (*queue_task) (task_manager_t *this, task_t *task);
119
120 /**
121 * @brief Retransmit a request if it hasn't been acknowledged yet.
122 *
123 * A return value of INVALID_STATE means that the message was already
124 * acknowledged and has not to be retransmitted. A return value of SUCCESS
125 * means retransmission was required and the message has been resent.
126 *
127 * @param this calling object
128 * @param message_id ID of the message to retransmit
129 * @return
130 * - INVALID_STATE if retransmission not required
131 * - SUCCESS if retransmission sent
132 */
133 status_t (*retransmit) (task_manager_t *this, u_int32_t message_id);
134
135 /**
136 * @brief Migrate all tasks from other to this.
137 *
138 * To rekey or reestablish an IKE_SA completely, all queued or active
139 * tasks should get migrated to the new IKE_SA.
140 *
141 * @param this manager which gets all tasks
142 * @param other manager which gives away its tasks
143 */
144 void (*adopt_tasks) (task_manager_t *this, task_manager_t *other);
145
146 /**
147 * @brief Reset message ID counters of the task manager.
148 *
149 * The IKEv2 protocol requires to restart exchanges with message IDs
150 * reset to zero (INVALID_KE_PAYLOAD, COOKIES, ...). The reset() method
151 * resets the message IDs and resets all active tasks using the migrate()
152 * method.
153 *
154 * @param this calling object
155 * @param other manager which gives away its tasks
156 */
157 void (*reset) (task_manager_t *this);
158
159 /**
160 * @brief Check if we are currently waiting for a reply.
161 *
162 * @param this calling object
163 * @return TRUE if we are waiting, FALSE otherwise
164 */
165 bool (*busy) (task_manager_t *this);
166
167 /**
168 * @brief Destroy the task_manager_t.
169 *
170 * @param this calling object
171 */
172 void (*destroy) (task_manager_t *this);
173 };
174
175 /**
176 * @brief Create an instance of the task manager.
177 *
178 * @param ike_sa IKE_SA to manage.
179 *
180 * @ingroup sa
181 */
182 task_manager_t *task_manager_create(ike_sa_t *ike_sa);
183
184 #endif /* TASK_MANAGER_H_ */