[strongswan.git] / Source / charon / ike_sa_manager.c

/**
 * @file ike_sa_manager.c
 *
 * @brief Central point for managing IKE-SAs (creation, locking, deleting...)
 *
 */

/*
 * Copyright (C) 2005 Jan Hutter, 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.
 */

#include <pthread.h>
#include <string.h>

#include "ike_sa_manager.h"

#include "globals.h"
#include "ike_sa_id.h"
#include "utils/allocator.h"
#include "utils/logger.h"
#include "utils/logger_manager.h"
#include "utils/linked_list.h"

/**
 * @brief An entry in the linked list, contains IKE_SA, locking and lookup data.
 */
typedef struct ike_sa_entry_s ike_sa_entry_t;
struct ike_sa_entry_s {
        /**
         * destructor, also destroys ike_sa
         */
        status_t (*destroy) (ike_sa_entry_t *this);
        /**
         * Number of threads waiting for this ike_sa
         */
        int waiting_threads;
        /**
         * condvar where threads can wait until it's free again
         */
        pthread_cond_t condvar;
        /**
         * is this ike_sa currently checked out?
         */
        bool checked_out;
        /**
         * Does this SA drives out new threads?
         */
        bool driveout_new_threads;
        /**
         * Does this SA drives out waiting threads?
         */
        bool driveout_waiting_threads;
        /**
         * identifiaction of ike_sa (SPIs)
         */
        ike_sa_id_t *ike_sa_id;
        /**
         * the contained ike_sa
         */
        ike_sa_t *ike_sa;
};

/**
 * @see ike_sa_entry_t.destroy
 */
static status_t ike_sa_entry_destroy(ike_sa_entry_t *this)
{
        /* also destroy IKE SA */
        this->ike_sa->destroy(this->ike_sa);
        this->ike_sa_id->destroy(this->ike_sa_id);
        allocator_free(this);
        return SUCCESS;
}

/**
 * @brief creates a new entry for the ike_sa list
 *
 * This constructor additionaly creates a new and empty SA
 *
 * @param ike_sa_id             the associated ike_sa_id_t, will be cloned
 * @return                              created entry, with ike_sa and ike_sa_id
 */
static ike_sa_entry_t *ike_sa_entry_create(ike_sa_id_t *ike_sa_id)
{
        ike_sa_entry_t *this = allocator_alloc_thing(ike_sa_entry_t);

        if (this == NULL)
        {
                return NULL;
        }

        /* destroy function */
        this->destroy = ike_sa_entry_destroy;
        
        this->waiting_threads = 0;
        pthread_cond_init(&(this->condvar), NULL);
        
        /* we set checkout flag when we really give it out */
        this->checked_out = FALSE;
        this->driveout_new_threads = FALSE;
        this->driveout_waiting_threads = FALSE;
        
        /* ike_sa_id is always cloned */
        ike_sa_id->clone(ike_sa_id, &(this->ike_sa_id));
        if (this->ike_sa_id == NULL)
        {
                allocator_free(this);   
                return NULL;
        }
        
        /* create new ike_sa */
        this->ike_sa = ike_sa_create(ike_sa_id);
        if (this->ike_sa == NULL)
        {
                this->ike_sa_id->destroy(this->ike_sa_id);
                allocator_free(this);   
                return NULL;
                
        }
        return this;
}

/**
 * Additional private members to ike_sa_manager_t
 */
typedef struct private_ike_sa_manager_s private_ike_sa_manager_t;
struct private_ike_sa_manager_s {
        /**
         * Public members
         */
         ike_sa_manager_t public;

        /**
         * @brief get next spi
         *
         * we give out SPIs incremental
         *
         * @param this                  the ike_sa_manager
         * @param spi[out]              spi will be written here
         * @return                              SUCCESS or,
         *                                              OUT_OF_RES when we already served 2^64 SPIs ;-)
         */
         status_t (*get_next_spi) (private_ike_sa_manager_t *this, u_int64_t *spi);

        /**
         * @brief find the ike_sa_entry in the list by SPIs
         *
         * This function simply iterates over the linked list. A hash-table
         * would be more efficient when storing a lot of IKE_SAs...
         *
         * @param this                  the ike_sa_manager containing the list
         * @param ike_sa_id             id of the ike_sa, containing SPIs
         * @param entry[out]    pointer to set to the found entry
         * @return                              
         *                                              - SUCCESS when found,
         *                                              - NOT_FOUND when no such ike_sa_id in list
         *                                              - OUT_OF_RES
         */
         status_t (*get_entry_by_id) (private_ike_sa_manager_t *this, ike_sa_id_t *ike_sa_id, ike_sa_entry_t **entry);

         /**
         * @brief find the ike_sa_entry in the list by pointer to SA.
         *
         * This function simply iterates over the linked list. A hash-table
         * would be more efficient when storing a lot of IKE_SAs...
         *
         * @param this                  the ike_sa_manager containing the list
         * @param ike_sa                        pointer to the ike_sa
         * @param entry[out]            pointer to set to the found entry
         * @return                              
         *                                              - SUCCESS when found,
         *                                              - NOT_FOUND when no such ike_sa_id in list
         *                                              - OUT_OF_RES
         */
         status_t (*get_entry_by_sa) (private_ike_sa_manager_t *this, ike_sa_t *ike_sa, ike_sa_entry_t **entry);
         
         /**
          * @brief delete an entry from the linked list
          *
          * @param this         the ike_sa_manager containing the list
          * @param entry                entry to delete
          * @return                             
          *                                     - SUCCESS when found,
          *                                     - NOT_FOUND when no such ike_sa_id in list
          */
         status_t (*delete_entry) (private_ike_sa_manager_t *this, ike_sa_entry_t *entry);

         /**
          * lock for exclusivly accessing the manager
          */
         pthread_mutex_t mutex;

         /**
          * Logger used for this IKE SA Manager
          */
         logger_t *logger;

         /**
          * Linked list with entries for the ike_sa
          */
         linked_list_t *ike_sa_list;
         
         /**
          * Next SPI, needed for incremental creation of SPIs
          */
         u_int64_t next_spi;
};


/**
 * @see private_ike_sa_manager_t.get_entry_by_id
 */
static status_t get_entry_by_id(private_ike_sa_manager_t *this, ike_sa_id_t *ike_sa_id, ike_sa_entry_t **entry)
{
        linked_list_t *list = this->ike_sa_list;
        linked_list_iterator_t *iterator;
        status_t status;
        
        /* create iterator over list of ike_sa's */
        status = list->create_iterator(list, &iterator, TRUE);
        if (status != SUCCESS)
        {
                this->logger->log(this->logger,ERROR,"Fatal Error: could not create iterator: %s",mapping_find(status_m,status));
                /* out of res */
                return status;
        }
        
        /* default status */
        status = NOT_FOUND;
        
        
        while (iterator->has_next(iterator))
        {
                ike_sa_entry_t *current;
                bool are_equal = FALSE;
                
                iterator->current(iterator, (void**)&current);
                if (current->ike_sa_id->get_responder_spi(current->ike_sa_id) == 0) {
                        /* seems to be a half ready ike_sa */
                        if ((current->ike_sa_id->get_initiator_spi(current->ike_sa_id) == ike_sa_id->get_initiator_spi(ike_sa_id))
                                && (ike_sa_id->is_initiator(ike_sa_id) == current->ike_sa_id->is_initiator(current->ike_sa_id)))
                        {
                                this->logger->log(this->logger,CONTROL | MOST,"Found entry by initiator spi %d",ike_sa_id->get_initiator_spi(ike_sa_id));
                                *entry = current;
                                status = SUCCESS;
                                break;
                        }
                }
                current->ike_sa_id->equals(current->ike_sa_id, ike_sa_id, &are_equal);
                if (are_equal)
                {
                        this->logger->log(this->logger,CONTROL | MOST,"Found entry by full ID");
                        *entry = current;
                        status = SUCCESS;
                        break;
                }
        }
        
        iterator->destroy(iterator);
        return status;
}

/**
 * @see private_ike_sa_manager_t.get_entry_by_sa
 */
static status_t get_entry_by_sa(private_ike_sa_manager_t *this, ike_sa_t *ike_sa, ike_sa_entry_t **entry)
{
        linked_list_t *list = this->ike_sa_list;
        linked_list_iterator_t *iterator;
        status_t status;
        
        status = list->create_iterator(list, &iterator, TRUE);
        if (status != SUCCESS)
        {
                this->logger->log(this->logger,ERROR,"Fatal Error: could not create iterator: %s",mapping_find(status_m,status));
                return status;
        }
        
        /* default status */
        status = NOT_FOUND;
        
        while (iterator->has_next(iterator))
        {
                ike_sa_entry_t *current;
                iterator->current(iterator, (void**)&current);
                /* only pointers are compared */
                if (current->ike_sa == ike_sa)
                {
                        this->logger->log(this->logger,CONTROL | MOST,"Found entry by pointer");
                        *entry = current;
                        status = SUCCESS;
                        break;
                }
        }
        iterator->destroy(iterator);
        return status;
}

/**
 * @see private_ike_sa_manager_s.delete_entry
 */
static status_t delete_entry(private_ike_sa_manager_t *this, ike_sa_entry_t *entry)
{
        linked_list_t *list = this->ike_sa_list;
        linked_list_iterator_t *iterator;
        status_t status;
        
        status = list->create_iterator(list, &iterator, TRUE);
        
        if (status != SUCCESS)
        {
                this->logger->log(this->logger,ERROR,"Fatal Error: could not create iterator: %s",mapping_find(status_m,status));
                return status;
        }

        status = NOT_FOUND;     
        
        while (iterator->has_next(iterator))
        {
                ike_sa_entry_t *current;
                iterator->current(iterator, (void**)&current);
                if (current == entry) 
                {
                        this->logger->log(this->logger,CONTROL | MOST,"Found entry by pointer. Going to delete it.");
                        list->remove(list, iterator);
                        entry->destroy(entry);
                        status = SUCCESS;
                        break;
                }
        }
        iterator->destroy(iterator);
        return status;  
}


/**
 * @see private_ike_sa_manager_t.get_next_spi
 */
static status_t get_next_spi(private_ike_sa_manager_t *this, u_int64_t *spi)
{
        this->next_spi++;
        if (this->next_spi == 0) {
                /* our software ran so incredible stable, we have no more
                 * SPIs to give away :-/.  */
                this->logger->log(this->logger,CONTROL | MOST,"No more SPI values available. WOW!");
                return OUT_OF_RES;
        }
        *spi = this->next_spi;
        return SUCCESS;
}

/**
 * @see ike_sa_manager_s.checkout_ike_sa
 */
static status_t checkout(private_ike_sa_manager_t *this, ike_sa_id_t *ike_sa_id, ike_sa_t **ike_sa)
{
        bool responder_spi_set;
        bool initiator_spi_set;
        status_t retval;

        /* each access is locked */
        pthread_mutex_lock(&(this->mutex));

        responder_spi_set = (FALSE != ike_sa_id->get_responder_spi(ike_sa_id));
        initiator_spi_set = (FALSE != ike_sa_id->get_initiator_spi(ike_sa_id));

        if (initiator_spi_set && responder_spi_set)
        {
                /* we SHOULD have an IKE_SA for these SPIs in the list,
                 * if not, we can't handle the request...
                 */
                 ike_sa_entry_t *entry;
                 /* look for the entry */
                 if (this->get_entry_by_id(this, ike_sa_id, &entry) == SUCCESS)
                 {
                        /* can we give this ike_sa out to new requesters?*/
                        if (entry->driveout_new_threads)
                        {
                                this->logger->log(this->logger,CONTROL|MORE,"Drive out new thread for existing IKE_SA");
                                /* no we can't */
                                retval = NOT_FOUND;
                        }
                        else
                        {
                                /* is this IKE_SA already checked out ?? 
                                 * are we welcome to get this SA ? */
                                while (entry->checked_out && !entry->driveout_waiting_threads)  
                                { 
                                        /* so wait until we can get it for us.
                                         * we register us as waiting.
                                         */
                                        entry->waiting_threads++;
                                        pthread_cond_wait(&(entry->condvar), &(this->mutex));
                                        entry->waiting_threads--;
                                }
                                
                                /* hm, a deletion request forbids us to get this SA, go home */
                                if (entry->driveout_waiting_threads)
                                {
                                        /* we must signal here, others are interested that we leave */
                                        pthread_cond_signal(&(entry->condvar));
                                        this->logger->log(this->logger,CONTROL|MORE,"Drive out waiting thread for existing IKE_SA");
                                        retval = NOT_FOUND;
                                }
                                else
                                {
                                        this->logger->log(this->logger,CONTROL|MOST,"IKE SA successfully checked out");
                                        /* ok, this IKE_SA is finally ours */
                                        entry->checked_out = TRUE;
                                        *ike_sa = entry->ike_sa;
                                        /* DON'T use return, we must unlock the mutex! */
                                        retval = SUCCESS; 
                                }
                        }
                 }
                 else
                 {
                        this->logger->log(this->logger,ERROR | MORE,"IKE SA not stored in known IKE_SA list");
                        /* looks like there is no such IKE_SA, better luck next time... */
                        /* DON'T use return, we must unlock the mutex! */
                        retval = NOT_FOUND;
                 }
        }
        else if (initiator_spi_set && !responder_spi_set)
        {
                /* an IKE_SA_INIT from an another endpoint,
                 * he is the initiator.
                 * For simplicity, we do NOT check for retransmitted
                 * IKE_SA_INIT-Requests here, so EVERY single IKE_SA_INIT-
                 * Request (even a retransmitted one) will result in a
                 * IKE_SA. This could be improved...
                 */
                u_int64_t responder_spi;
                ike_sa_entry_t *new_ike_sa_entry;
                

                /* set SPIs, we are the responder */
                retval = this->get_next_spi(this, &responder_spi);

                if (retval == SUCCESS)
                { /* next SPI could be created */
                        
                        /* we also set arguments spi, so its still valid */
                        ike_sa_id->set_responder_spi(ike_sa_id, responder_spi);
                        
                        /* create entry */
                        new_ike_sa_entry = ike_sa_entry_create(ike_sa_id);
                        if (new_ike_sa_entry != NULL)
                        { 
                                retval = this->ike_sa_list->insert_last(this->ike_sa_list, new_ike_sa_entry);
                                if (retval == SUCCESS)
                                {
                                        /* check ike_sa out */
                                        this->logger->log(this->logger,CONTROL | MORE ,"IKE_SA added to list of known IKE_SA's");
                                        new_ike_sa_entry->checked_out = TRUE;
                                        *ike_sa = new_ike_sa_entry->ike_sa;
                        
                                         /* DON'T use return, we must unlock the mutex! */
                                }
                                else
                                {
                                        /* ike_sa_entry could not be added to list*/
                                        this->logger->log(this->logger,ERROR,"Fatal error: ike_sa_entry could not be added to list");
                                }                       
                        }
                        else
                        {
                                /* new ike_sa_entry could not be created */
                                this->logger->log(this->logger,ERROR,"Fatal error: ike_sa_entry could not be created");                 
                        }
                }
                else
                { /* next SPI could not be created */
                        this->logger->log(this->logger,ERROR,"Fatal error: Next SPI could not be created");
                }
                
        }
        else if (!initiator_spi_set && !responder_spi_set)
        {
                /* creation of an IKE_SA from local site,
                 * we are the initiator!
                 */
                u_int64_t initiator_spi;
                ike_sa_entry_t *new_ike_sa_entry;
                
                retval = this->get_next_spi(this, &initiator_spi);
                if (retval == SUCCESS)
                {
                        /* we also set arguments SPI, so its still valid */
                        ike_sa_id->set_initiator_spi(ike_sa_id, initiator_spi);

                        /* create entry */
                        new_ike_sa_entry = ike_sa_entry_create(ike_sa_id);
                        if (new_ike_sa_entry != NULL)
                        { 
                                retval = this->ike_sa_list->insert_last(this->ike_sa_list, new_ike_sa_entry);

                                if (retval == SUCCESS)
                                {
                                        /* check ike_sa out */
                                        this->logger->log(this->logger,CONTROL | MORE ,"New IKE_SA created and added to list of known IKE_SA's");
                                        new_ike_sa_entry->checked_out = TRUE;
                                        *ike_sa = new_ike_sa_entry->ike_sa;
                        
                                        /* DON'T use return, we must unlock the mutex! */
                                }
                                else
                                {
                                        /* ike_sa_entry could not be added to list*/
                                        this->logger->log(this->logger,ERROR,"Fatal error: ike_sa_entry could not be added to list");
                                }               
                        }
                        else
                        {
                                /* new ike_sa_entry could not be created */
                                this->logger->log(this->logger,ERROR,"Fatal error: ike_sa_entry could not be created"); 
                        }
                }
                else
                {
                        /* next SPI could not be created */
                        this->logger->log(this->logger,ERROR,"Fatal error: Next SPI could not be created");
                }


        }
        else
        {
                /* responder set, initiator not: here is something seriously wrong! */
                this->logger->log(this->logger,ERROR | MORE,"Invalid IKE_SA SPI's");
                /* DON'T use return, we must unlock the mutex! */
                retval = INVALID_ARG;
        }

        pthread_mutex_unlock(&(this->mutex));
        /* OK, unlocked... */
        return retval;
}

/**
 * Implements ike_sa_manager_t-function checkin.
 * @see ike_sa_manager_t.checkin.
 */
static status_t checkin(private_ike_sa_manager_t *this, ike_sa_t *ike_sa)
{
        /* to check the SA back in, we look for the pointer of the ike_sa
         * in all entries.
         * We can't search by SPI's since the MAY have changed (e.g. on reception
         * of a IKE_SA_INIT response). Updating of the SPI MAY be necessary...
         */
        status_t retval;
        ike_sa_entry_t *entry;
        
        pthread_mutex_lock(&(this->mutex));

        /* look for the entry */
        if (this->get_entry_by_sa(this, ike_sa, &entry) == SUCCESS)
        {
                /* ike_sa_id must be updated */
                entry->ike_sa_id->replace_values(entry->ike_sa_id, ike_sa->get_id(ike_sa));
                /* signal waiting threads */
                entry->checked_out = FALSE;
                this->logger->log(this->logger,CONTROL | MORE,"Checkin of IKE_SA successful.");
                pthread_cond_signal(&(entry->condvar));
                retval = SUCCESS;
        }
        else
        {
                this->logger->log(this->logger,ERROR,"Fatal Error: Tried to checkin nonexisting IKE_SA");
                /* this SA is no more, this REALLY should not happen */
                retval = NOT_FOUND;
        }
        pthread_mutex_unlock(&(this->mutex));
        return retval;
}


/**
 * Implements ike_sa_manager_t-function checkin_and_delete.
 * @see ike_sa_manager_t.checkin_and_delete.
 */
static status_t checkin_and_delete(private_ike_sa_manager_t *this, ike_sa_t *ike_sa)
{
        /* deletion is a bit complex, we must garant that no thread is waiting for
         * this SA.
         * We take this SA from the list, and start signaling while threads
         * are in the condvar.
         */
        ike_sa_entry_t *entry;
        status_t retval;

        pthread_mutex_lock(&(this->mutex));

        if (this->get_entry_by_sa(this, ike_sa, &entry) == SUCCESS)
        {
                /* mark it, so now new threads can acquire this SA */
                entry->driveout_new_threads = TRUE;
                /* additionaly, drive out waiting threads */
                entry->driveout_waiting_threads = TRUE;

                /* wait until all workers have done their work */
                while (entry->waiting_threads > 0)
                {
                        /* let the other threads do some work*/
                        pthread_cond_signal(&(entry->condvar));
                        /* and the nice thing, they will wake us again when their work is done */
                        pthread_cond_wait(&(entry->condvar), &(this->mutex));
                }
                /* ok, we are alone now, no threads waiting in the entry's condvar */
                this->delete_entry(this, entry);
                this->logger->log(this->logger,CONTROL | MORE,"Checkin and delete of IKE_SA successful");
                retval = SUCCESS;
        }
        else
        {
                this->logger->log(this->logger,ERROR,"Fatal Error: Tried to checkin and delete nonexisting IKE_SA");
                retval = NOT_FOUND;
        }

        pthread_mutex_unlock(&(this->mutex));
        return retval;
}

/**
 * Implements ike_sa_manager_t-function delete.
 * @see ike_sa_manager_t.delete.
 */
static status_t delete(private_ike_sa_manager_t *this, ike_sa_id_t *ike_sa_id)
{
        /* deletion is a bit complex, we must garant that no thread is waiting for
         * this SA.
         * We take this SA from the list, and start signaling while threads
         * are in the condvar.
         */
        ike_sa_entry_t *entry;
        status_t retval;

        pthread_mutex_lock(&(this->mutex));

        if (this->get_entry_by_id(this, ike_sa_id, &entry) == SUCCESS)
        {
                /* mark it, so now new threads can acquire this SA */
                entry->driveout_new_threads = TRUE;

                /* wait until all workers have done their work */
                while (entry->waiting_threads)
                {
                        /* wake up all */
                        pthread_cond_signal(&(entry->condvar));
                        /* and the nice thing, they will wake us again when their work is done */
                        pthread_cond_wait(&(entry->condvar), &(this->mutex));
                }
                /* ok, we are alone now, no threads waiting in the entry's condvar */
                this->delete_entry(this, entry);
                this->logger->log(this->logger,CONTROL | MORE,"Delete of IKE_SA successful");
                retval = SUCCESS;
        }
        else
        {
                this->logger->log(this->logger,ERROR,"Fatal Error: Tried to delete nonexisting IKE_SA");
                retval = NOT_FOUND;
        }

        pthread_mutex_unlock(&(this->mutex));
        return retval;
}

/**
 * Implements ike_sa_manager_t-function destroy.
 * @see ike_sa_manager_t.destroy.
 */
static status_t destroy(private_ike_sa_manager_t *this)
{
        /* destroy all list entries */
        linked_list_t *list = this->ike_sa_list;
        linked_list_iterator_t *iterator;
        status_t status;
        
        pthread_mutex_lock(&(this->mutex));
        
        this->logger->log(this->logger,CONTROL | MORE,"Going to destroy IKE_SA manager and all managed IKE_SA's");
        
        /* Step 1: drive out all waiting threads  */
        status = list->create_iterator(list, &iterator, TRUE);
        
        if (status != SUCCESS)
        {
                this->logger->log(this->logger,ERROR,"Fatal Error: Create of iterator while destroying IKE_SA-Manager failed");
                return FAILED;
        }

        this->logger->log(this->logger,CONTROL | MOST,"Set driveout flags for all stored IKE_SA's");
        while (iterator->has_next(iterator))
        {
                ike_sa_entry_t *entry;
                iterator->current(iterator, (void**)&entry);
                /* do not accept new threads, drive out waiting threads */
                entry->driveout_new_threads = TRUE;
                entry->driveout_waiting_threads = TRUE; 
        }

        this->logger->log(this->logger,CONTROL | MOST,"Wait for all threads to leave IKE_SA's");
        /* Step 2: wait until all are gone */
        iterator->reset(iterator);
        while (iterator->has_next(iterator))
        {
                ike_sa_entry_t *entry;
                iterator->current(iterator, (void**)&entry);
                while (entry->waiting_threads)
                {
                        /* wake up all */
                        pthread_cond_signal(&(entry->condvar));
                        /* go sleeping until they are gone */
                        pthread_cond_wait(&(entry->condvar), &(this->mutex));           
                }
        }
        this->logger->log(this->logger,CONTROL | MOST,"Delete all IKE_SA's");
        /* Step 3: delete all entries */
        iterator->reset(iterator);
        while (iterator->has_next(iterator))
        {
                ike_sa_entry_t *entry;
                iterator->current(iterator, (void**)&entry);
                this->delete_entry(this, entry);
        }
        iterator->destroy(iterator);

        list->destroy(list);
        pthread_mutex_unlock(&(this->mutex));
        
        /* destroy logger at end */
        global_logger_manager->destroy_logger(global_logger_manager,this->logger);
        allocator_free(this);
        
        return SUCCESS;
}

/*
 * Described in header
 */
ike_sa_manager_t *ike_sa_manager_create()
{
        private_ike_sa_manager_t *this = allocator_alloc_thing(private_ike_sa_manager_t);

        /* assign public functions */
        this->public.destroy = (status_t(*)(ike_sa_manager_t*))destroy;
        this->public.checkout = (status_t(*)(ike_sa_manager_t*, ike_sa_id_t *sa_id, ike_sa_t **sa))checkout;
        this->public.checkin = (status_t(*)(ike_sa_manager_t*, ike_sa_t *sa))checkin;
        this->public.delete = (status_t(*)(ike_sa_manager_t*, ike_sa_id_t *sa_id))delete;
        this->public.checkin_and_delete = (status_t(*)(ike_sa_manager_t*, ike_sa_t *ike_sa))checkin_and_delete;

        /* initialize private functions */
        this->get_next_spi = get_next_spi;
        this->get_entry_by_sa = get_entry_by_sa;
        this->get_entry_by_id = get_entry_by_id;
        this->delete_entry = delete_entry;

        /* initialize private variables */
        this->logger = global_logger_manager->create_logger(global_logger_manager,IKE_SA_MANAGER,NULL);
        if (this->logger == NULL)
        {
                allocator_free(this);
                return NULL;
        }
        
        this->ike_sa_list = linked_list_create();
        if (this->ike_sa_list == NULL)
        {
                this->logger->log(this->logger,ERROR,"Fatal error: Failed to create list for managed IKE_SA");
                global_logger_manager->destroy_logger(global_logger_manager,this->logger);
                allocator_free(this);
                return NULL;
        }

        pthread_mutex_init(&(this->mutex), NULL);

        this->next_spi = 0;

        return (ike_sa_manager_t*)this;
}