root/trunk/src/charon/sa/ike_sa_manager.h

/*
 * Copyright (C) 2008 Tobias Brunner
 * Copyright (C) 2005-2008 Martin Willi
 * Copyright (C) 2005 Jan Hutter
 * 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.
 *
 * $Id$
 */

/**
 * @defgroup ike_sa_manager ike_sa_manager
 * @{ @ingroup sa
 */

#ifndef IKE_SA_MANAGER_H_
#define IKE_SA_MANAGER_H_

typedef struct ike_sa_manager_t ike_sa_manager_t;

#include <library.h>
#include <sa/ike_sa.h>
#include <encoding/message.h>
#include <config/peer_cfg.h>

/**
 * Manages and synchronizes access to all IKE_SAs.
 *
 * To synchronize access to thread-unsave IKE_SAs, they are checked out for
 * use and checked in afterwards. A checked out SA is exclusively accessible
 * by the owning thread.
 */
struct ike_sa_manager_t {
    
    /**
     * Checkout an existing IKE_SA.
     * 
     * @param ike_sa_id         the SA identifier, will be updated
     * @returns                     
     *                          - checked out IKE_SA if found
     *                          - NULL, if specified IKE_SA is not found.
     */
    ike_sa_t* (*checkout) (ike_sa_manager_t* this, ike_sa_id_t *sa_id);
    
    /**
     * Create and check out a new IKE_SA.
     *
     * @param initiator         TRUE for initiator, FALSE otherwise
     * @returns                 created and checked out IKE_SA
     */
    ike_sa_t* (*checkout_new) (ike_sa_manager_t* this, bool initiator);
    
    /**
     * Checkout an IKE_SA by a message.
     * 
     * In some situations, it is necessary that the manager knows the
     * message to use for the checkout. This has the following reasons:
     * 
     * 1. If the targeted IKE_SA is already processing a message, we do not
     *    check it out if the message ID is the same.
     * 2. If it is an IKE_SA_INIT request, we have to check if it is a 
     *    retransmission. If so, we have to drop the message, we would
     *    create another unneeded IKE_SA for each retransmitted packet.
     *
     * A call to checkout_by_message() returns a (maybe new created) IKE_SA.
     * If processing the message does not make sense (for the reasons above),
     * NULL is returned.
     * 
     * @param ike_sa_id         the SA identifier, will be updated
     * @returns                     
     *                          - checked out/created IKE_SA
     *                          - NULL to not process message further
     */
    ike_sa_t* (*checkout_by_message) (ike_sa_manager_t* this, message_t *message);
    
    /**
     * Checkout an IKE_SA for initiation by a peer_config.
     *
     * To initiate, a CHILD_SA may be established within an existing IKE_SA.
     * This call checks for an existing IKE_SA by comparing the configuration.
     * If the CHILD_SA can be created in an existing IKE_SA, the matching SA
     * is returned.
     * If no IKE_SA is found, a new one is created. This is also the case when
     * the found IKE_SA is in the DELETING state.
     *
     * @param peer_cfg          configuration used to find an existing IKE_SA
     * @return                  checked out/created IKE_SA
     */
    ike_sa_t* (*checkout_by_config) (ike_sa_manager_t* this,
                                     peer_cfg_t *peer_cfg);
    
    /**
     * Check for duplicates of the given IKE_SA.
     * 
     * Measures are taken according to the uniqueness policy of the IKE_SA.
     * The return value indicates whether duplicates have been found and if
     * further measures should be taken (e.g. cancelling an IKE_AUTH exchange).
     * check_uniqueness() must be called before the IKE_SA is complete,
     * deadlocks occur otherwise.
     * 
     * @param ike_sa            ike_sa to check
     * @return                  TRUE, if the given IKE_SA has duplicates and
     *                          should be deleted
     */
    bool (*check_uniqueness)(ike_sa_manager_t *this, ike_sa_t *ike_sa);
    
    /**
     * Check out an IKE_SA a unique ID.
     *
     * Every IKE_SA and every CHILD_SA is uniquely identified by an ID. 
     * These checkout function uses, depending
     * on the child parameter, the unique ID of the IKE_SA or the reqid
     * of one of a IKE_SAs CHILD_SA.
     *
     * @param id                unique ID of the object
     * @param child             TRUE to use CHILD, FALSE to use IKE_SA
     * @return
     *                          - checked out IKE_SA, if found
     *                          - NULL, if not found
     */
    ike_sa_t* (*checkout_by_id) (ike_sa_manager_t* this, u_int32_t id,
                                 bool child);
    
    /**
     * Check out an IKE_SA by the policy/connection name.
     *
     * Check out the IKE_SA by the configuration name, either from the IKE- or
     * one of its CHILD_SAs.
     *
     * @param name              name of the connection/policy
     * @param child             TRUE to use policy name, FALSE to use conn name
     * @return
     *                          - checked out IKE_SA, if found
     *                          - NULL, if not found
     */
    ike_sa_t* (*checkout_by_name) (ike_sa_manager_t* this, char *name,
                                   bool child);
    
    /**
     * Create an enumerator over all stored IKE_SAs.
     *
     * While enumerating an IKE_SA, it is temporarily checked out and
     * automatically checked in after the current enumeration step.
     *
     * @return                  enumerator over all IKE_SAs.
     */
    enumerator_t *(*create_enumerator) (ike_sa_manager_t* this);
    
    /**
     * Checkin the SA after usage.
     *
     * If the IKE_SA is not registered in the manager, a new entry is created.
     *
     * @param ike_sa_id         the SA identifier, will be updated
     * @param ike_sa            checked out SA
     */
    void (*checkin) (ike_sa_manager_t* this, ike_sa_t *ike_sa);
    
    /**
     * Destroy a checked out SA.
     *
     * The IKE SA is destroyed without notification of the remote peer.
     * Use this only if the other peer doesn't respond or behaves not
     * as predicted.
     * Checking in and destruction is an atomic operation (for the IKE_SA),
     * so this can be called if the SA is in a "unclean" state, without the
     * risk that another thread can get the SA.
     *
     * @param ike_sa            SA to delete
     */
    void (*checkin_and_destroy) (ike_sa_manager_t* this, ike_sa_t *ike_sa);
    
    /**
     * Get the number of IKE_SAs which are in the connecting state.
     *
     * To prevent the server from resource exhaustion, cookies and other
     * mechanisms are used. The number of half open IKE_SAs is a good
     * indicator to see if a peer is flooding the server.
     * If a host is supplied, only the number of half open IKE_SAs initiated
     * from this IP are counted.
     * Only SAs for which we are the responder are counted.
     * 
     * @param ip                NULL for all, IP for half open IKE_SAs with IP
     * @return                  number of half open IKE_SAs
     */
    int (*get_half_open_count) (ike_sa_manager_t *this, host_t *ip);
    
    /**
     * Delete all existing IKE_SAs and destroy them immediately.
     * 
     * Threads will be driven out, so all SAs can be deleted cleanly.
     */
    void (*flush)(ike_sa_manager_t *this);
    
    /**
     * Destroys the manager with all associated SAs.
     *
     * A call to flush() is required before calling destroy.
     */
    void (*destroy) (ike_sa_manager_t *this);
};

/**
 * Create the IKE_SA manager.
 * 
 * @returns     ike_sa_manager_t object, NULL if initialization fails
 */
ike_sa_manager_t *ike_sa_manager_create(void);

#endif /*IKE_SA_MANAGER_H_ @} */