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/*
* Copyright (C) 2006 Martin Willi
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
/**
* @defgroup task_manager task_manager
* @{ @ingroup sa
*/
#ifndef TASK_MANAGER_H_
#define TASK_MANAGER_H_
typedef struct task_manager_t task_manager_t;
#include <limits.h>
#include <library.h>
#include <encoding/message.h>
#include <sa/ike_sa.h>
#include <sa/tasks/task.h>
/**
* First retransmit timeout in milliseconds.
*/
#define RETRANSMIT_TIMEOUT 4000
/**
* Base which is raised to the power of the retransmission try.
*/
#define RETRANSMIT_BASE 1.8
/**
* Number of retransmits done before giving up.
*/
#define RETRANSMIT_TRIES 5
/**
* Interval for mobike routability checks in ms.
*/
#define ROUTEABILITY_CHECK_INTERVAL 2500
/**
* Number of routability checks before giving up
*/
#define ROUTEABILITY_CHECK_TRIES 10
/**
* The task manager, juggles task and handles message exchanges.
*
* On incoming requests, the task manager creates new tasks on demand and
* juggles the request through all available tasks. Each task inspects the
* request and adds payloads as necessary to the response.
* On outgoing requests, the task manager delivers the request through the tasks
* to build it, the response gets processed by each task to complete.
* The task manager has an internal Queue to store task which should get
* completed.
* For the initial IKE_SA setup, several tasks are queued: One for the
* unauthenticated IKE_SA setup, one for authentication, one for CHILD_SA setup
* and maybe one for virtual IP assignement.
* The task manager is also responsible for retransmission. It uses a backoff
* algorithm. The timeout is calculated using
* RETRANSMIT_TIMEOUT * (RETRANSMIT_BASE ** try).
* When try reaches RETRANSMIT_TRIES, retransmission is given up.
*
* Using an initial TIMEOUT of 4s, a BASE of 1.8, and 5 TRIES gives us:
* @verbatim
| relative | absolute
---------------------------------------------------------
4s * (1.8 ** 0) = 4s 4s
4s * (1.8 ** 1) = 7s 11s
4s * (1.8 ** 2) = 13s 24s
4s * (1.8 ** 3) = 23s 47s
4s * (1.8 ** 4) = 42s 89s
4s * (1.8 ** 5) = 76s 165s
@endverbatim
* The peer is considered dead after 2min 45s when no reply comes in.
*/
struct task_manager_t {
/**
* Process an incoming message.
*
* @param message message to add payloads to
* @return
* - DESTROY_ME if IKE_SA must be closed
* - SUCCESS otherwise
*/
status_t (*process_message) (task_manager_t *this, message_t *message);
/**
* Initiate an exchange with the currently queued tasks.
*/
status_t (*initiate) (task_manager_t *this);
/**
* Queue a task in the manager.
*
* @param task task to queue
*/
void (*queue_task) (task_manager_t *this, task_t *task);
/**
* Retransmit a request if it hasn't been acknowledged yet.
*
* A return value of INVALID_STATE means that the message was already
* acknowledged and has not to be retransmitted. A return value of SUCCESS
* means retransmission was required and the message has been resent.
*
* @param message_id ID of the message to retransmit
* @return
* - INVALID_STATE if retransmission not required
* - SUCCESS if retransmission sent
*/
status_t (*retransmit) (task_manager_t *this, u_int32_t message_id);
/**
* Migrate all tasks from other to this.
*
* To rekey or reestablish an IKE_SA completely, all queued or active
* tasks should get migrated to the new IKE_SA.
*
* @param other manager which gives away its tasks
*/
void (*adopt_tasks) (task_manager_t *this, task_manager_t *other);
/**
* Reset message ID counters of the task manager.
*
* The IKEv2 protocol requires to restart exchanges with message IDs
* reset to zero (INVALID_KE_PAYLOAD, COOKIES, ...). The reset() method
* resets the message IDs and resets all active tasks using the migrate()
* method.
* Use a value of UINT_MAX to keep the current message ID.
*
* @param initiate message ID to initiate exchanges (send)
* @param respond message ID to respond to exchanges (expect)
*/
void (*reset) (task_manager_t *this, u_int32_t initiate, u_int32_t respond);
/**
* Check if we are currently waiting for a reply.
*
* @return TRUE if we are waiting, FALSE otherwise
*/
bool (*busy) (task_manager_t *this);
/**
* Destroy the task_manager_t.
*/
void (*destroy) (task_manager_t *this);
};
/**
* Create an instance of the task manager.
*
* @param ike_sa IKE_SA to manage.
*/
task_manager_t *task_manager_create(ike_sa_t *ike_sa);
#endif /** TASK_MANAGER_H_ @}*/
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