implemented more aggressive MOBIKE path probing
[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 * Interval for mobike routability checks in ms.
56 *
57 * @ingroup sa
58 */
59 #define ROUTEABILITY_CHECK_INTERVAL 2500
60
61 /**
62 * Number of routability checks before giving up
63 *
64 * @ingroup sa
65 */
66 #define ROUTEABILITY_CHECK_TRIES 10
67
68
69 /**
70 * @brief The task manager, juggles task and handles message exchanges.
71 *
72 * On incoming requests, the task manager creates new tasks on demand and
73 * juggles the request through all available tasks. Each task inspects the
74 * request and adds payloads as necessary to the response.
75 * On outgoing requests, the task manager delivers the request through the tasks
76 * to build it, the response gets processed by each task to complete.
77 * The task manager has an internal Queue to store task which should get
78 * completed.
79 * For the initial IKE_SA setup, several tasks are queued: One for the
80 * unauthenticated IKE_SA setup, one for authentication, one for CHILD_SA setup
81 * and maybe one for virtual IP assignement.
82 * The task manager is also responsible for retransmission. It uses a backoff
83 * algorithm. The timeout is calculated using
84 * RETRANSMIT_TIMEOUT * (RETRANSMIT_BASE ** try).
85 * When try reaches RETRANSMIT_TRIES, retransmission is given up.
86 *
87 * Using an initial TIMEOUT of 4s, a BASE of 1.8, and 5 TRIES gives us:
88 * @verbatim
89 | relative | absolute
90 ---------------------------------------------------------
91 4s * (1.8 ** 0) = 4s 4s
92 4s * (1.8 ** 1) = 7s 11s
93 4s * (1.8 ** 2) = 13s 24s
94 4s * (1.8 ** 3) = 23s 47s
95 4s * (1.8 ** 4) = 42s 89s
96 4s * (1.8 ** 5) = 76s 165s
97
98 @endberbatim
99 * The peer is considered dead after 2min 45s when no reply comes in.
100 *
101 * @b Constructors:
102 * - task_manager_create()
103 *
104 * @ingroup sa
105 */
106 struct task_manager_t {
107
108 /**
109 * @brief Process an incoming message.
110 *
111 * @param this calling object
112 * @param message message to add payloads to
113 * @return
114 * - DESTROY_ME if IKE_SA must be closed
115 * - SUCCESS otherwise
116 */
117 status_t (*process_message) (task_manager_t *this, message_t *message);
118
119 /**
120 * @brief Initiate an exchange with the currently queued tasks.
121 *
122 * @param this calling object
123 */
124 status_t (*initiate) (task_manager_t *this);
125
126 /**
127 * @brief Queue a task in the manager.
128 *
129 * @param this calling object
130 * @param task task to queue
131 */
132 void (*queue_task) (task_manager_t *this, task_t *task);
133
134 /**
135 * @brief Retransmit a request if it hasn't been acknowledged yet.
136 *
137 * A return value of INVALID_STATE means that the message was already
138 * acknowledged and has not to be retransmitted. A return value of SUCCESS
139 * means retransmission was required and the message has been resent.
140 *
141 * @param this calling object
142 * @param message_id ID of the message to retransmit
143 * @return
144 * - INVALID_STATE if retransmission not required
145 * - SUCCESS if retransmission sent
146 */
147 status_t (*retransmit) (task_manager_t *this, u_int32_t message_id);
148
149 /**
150 * @brief Migrate all tasks from other to this.
151 *
152 * To rekey or reestablish an IKE_SA completely, all queued or active
153 * tasks should get migrated to the new IKE_SA.
154 *
155 * @param this manager which gets all tasks
156 * @param other manager which gives away its tasks
157 */
158 void (*adopt_tasks) (task_manager_t *this, task_manager_t *other);
159
160 /**
161 * @brief Reset message ID counters of the task manager.
162 *
163 * The IKEv2 protocol requires to restart exchanges with message IDs
164 * reset to zero (INVALID_KE_PAYLOAD, COOKIES, ...). The reset() method
165 * resets the message IDs and resets all active tasks using the migrate()
166 * method.
167 *
168 * @param this calling object
169 * @param other manager which gives away its tasks
170 */
171 void (*reset) (task_manager_t *this);
172
173 /**
174 * @brief Check if we are currently waiting for a reply.
175 *
176 * @param this calling object
177 * @return TRUE if we are waiting, FALSE otherwise
178 */
179 bool (*busy) (task_manager_t *this);
180
181 /**
182 * @brief Destroy the task_manager_t.
183 *
184 * @param this calling object
185 */
186 void (*destroy) (task_manager_t *this);
187 };
188
189 /**
190 * @brief Create an instance of the task manager.
191 *
192 * @param ike_sa IKE_SA to manage.
193 *
194 * @ingroup sa
195 */
196 task_manager_t *task_manager_create(ike_sa_t *ike_sa);
197
198 #endif /* TASK_MANAGER_H_ */