7de249ff93e301322bb685f253ef8380a7dff082
[strongswan.git] / src / charon / sa / task_manager.h
1 /*
2 * Copyright (C) 2006 Martin Willi
3 * Hochschule fuer Technik Rapperswil
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
12 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * for more details.
14 *
15 * $Id$
16 */
17
18 /**
19 * @defgroup task_manager task_manager
20 * @{ @ingroup sa
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 <limits.h>
29
30 #include <library.h>
31 #include <encoding/message.h>
32 #include <sa/ike_sa.h>
33 #include <sa/tasks/task.h>
34
35 /**
36 * First retransmit timeout in milliseconds.
37 */
38 #define RETRANSMIT_TIMEOUT 4000
39
40 /**
41 * Base which is raised to the power of the retransmission try.
42 */
43 #define RETRANSMIT_BASE 1.8
44
45 /**
46 * Number of retransmits done before giving up.
47 */
48 #define RETRANSMIT_TRIES 5
49
50 /**
51 * Interval for mobike routability checks in ms.
52 */
53 #define ROUTEABILITY_CHECK_INTERVAL 2500
54
55 /**
56 * Number of routability checks before giving up
57 */
58 #define ROUTEABILITY_CHECK_TRIES 10
59
60
61 /**
62 * The task manager, juggles task and handles message exchanges.
63 *
64 * On incoming requests, the task manager creates new tasks on demand and
65 * juggles the request through all available tasks. Each task inspects the
66 * request and adds payloads as necessary to the response.
67 * On outgoing requests, the task manager delivers the request through the tasks
68 * to build it, the response gets processed by each task to complete.
69 * The task manager has an internal Queue to store task which should get
70 * completed.
71 * For the initial IKE_SA setup, several tasks are queued: One for the
72 * unauthenticated IKE_SA setup, one for authentication, one for CHILD_SA setup
73 * and maybe one for virtual IP assignement.
74 * The task manager is also responsible for retransmission. It uses a backoff
75 * algorithm. The timeout is calculated using
76 * RETRANSMIT_TIMEOUT * (RETRANSMIT_BASE ** try).
77 * When try reaches RETRANSMIT_TRIES, retransmission is given up.
78 *
79 * Using an initial TIMEOUT of 4s, a BASE of 1.8, and 5 TRIES gives us:
80 * @verbatim
81 | relative | absolute
82 ---------------------------------------------------------
83 4s * (1.8 ** 0) = 4s 4s
84 4s * (1.8 ** 1) = 7s 11s
85 4s * (1.8 ** 2) = 13s 24s
86 4s * (1.8 ** 3) = 23s 47s
87 4s * (1.8 ** 4) = 42s 89s
88 4s * (1.8 ** 5) = 76s 165s
89
90 @endverbatim
91 * The peer is considered dead after 2min 45s when no reply comes in.
92 */
93 struct task_manager_t {
94
95 /**
96 * Process an incoming message.
97 *
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 * Initiate an exchange with the currently queued tasks.
107 */
108 status_t (*initiate) (task_manager_t *this);
109
110 /**
111 * Queue a task in the manager.
112 *
113 * @param task task to queue
114 */
115 void (*queue_task) (task_manager_t *this, task_t *task);
116
117 /**
118 * Retransmit a request if it hasn't been acknowledged yet.
119 *
120 * A return value of INVALID_STATE means that the message was already
121 * acknowledged and has not to be retransmitted. A return value of SUCCESS
122 * means retransmission was required and the message has been resent.
123 *
124 * @param message_id ID of the message to retransmit
125 * @return
126 * - INVALID_STATE if retransmission not required
127 * - SUCCESS if retransmission sent
128 */
129 status_t (*retransmit) (task_manager_t *this, u_int32_t message_id);
130
131 /**
132 * Migrate all tasks from other to this.
133 *
134 * To rekey or reestablish an IKE_SA completely, all queued or active
135 * tasks should get migrated to the new IKE_SA.
136 *
137 * @param other manager which gives away its tasks
138 */
139 void (*adopt_tasks) (task_manager_t *this, task_manager_t *other);
140
141 /**
142 * Reset message ID counters of the task manager.
143 *
144 * The IKEv2 protocol requires to restart exchanges with message IDs
145 * reset to zero (INVALID_KE_PAYLOAD, COOKIES, ...). The reset() method
146 * resets the message IDs and resets all active tasks using the migrate()
147 * method.
148 * Use a value of UINT_MAX to keep the current message ID.
149 *
150 * @param initiate message ID to initiate exchanges (send)
151 * @param respond message ID to respond to exchanges (expect)
152 */
153 void (*reset) (task_manager_t *this, u_int32_t initiate, u_int32_t respond);
154
155 /**
156 * Check if we are currently waiting for a reply.
157 *
158 * @return TRUE if we are waiting, FALSE otherwise
159 */
160 bool (*busy) (task_manager_t *this);
161
162 /**
163 * Destroy the task_manager_t.
164 */
165 void (*destroy) (task_manager_t *this);
166 };
167
168 /**
169 * Create an instance of the task manager.
170 *
171 * @param ike_sa IKE_SA to manage.
172 */
173 task_manager_t *task_manager_create(ike_sa_t *ike_sa);
174
175 #endif /** TASK_MANAGER_H_ @}*/