/* Copyright (C) 2007-2012 Open Information Security Foundation

 *

 * You can copy, redistribute or modify this Program under the terms of

 * the GNU General Public License version 2 as published by the Free

 * Software Foundation.

 *

 * 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.

 *

 * You should have received a copy of the GNU General Public License

 * version 2 along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

/**

 * \file

 *

 * \author Victor Julien <victor@inliniac.net>

 */

#include "suricata-common.h"

#include "ippair.h"

#include "ippair-bit.h"

#include "ippair-timeout.h"

#include "detect-engine-threshold.h"

uint32_t IPPairGetSpareCount(void)

{

    return IPPairSpareQueueGetSize();

}

uint32_t IPPairGetActiveCount(void)

{

    return SC_ATOMIC_GET(ippair_counter);

}

/** \internal

 *  \brief See if we can really discard this ippair. Check use_cnt reference.

 *

 *  \param h ippair

 *  \param ts timestamp

 *

 *  \retval 0 not timed out just yet

 *  \retval 1 fully timed out, lets kill it

 */

static int IPPairTimedOut(IPPair *h, SCTime_t ts)

{

    int vars = 0;

    int thresholds = 0;

    /** never prune a ippair that is used by a packet

     *  we are currently processing in one of the threads */

    if (SC_ATOMIC_GET(h->use_cnt) > 0) {

        return 0;

    }

    if (IPPairHasBits(h) && IPPairBitsTimedoutCheck(h, ts) == 0) {

        vars = 1;

    }

    if (ThresholdIPPairHasThreshold(h) && ThresholdIPPairTimeoutCheck(h, ts) == 0) {

        thresholds = 1;

    }

    if (vars || thresholds) {

        return 0;

    }

    SCLogDebug("ippair %p timed out", h);

    return 1;

}

/**

 *  \internal

 *

 *  \brief check all ippairs in a hash row for timing out

 *

 *  \param hb ippair hash row *LOCKED*

 *  \param h last ippair in the hash row

 *  \param ts timestamp

 *

 *  \retval cnt timed out ippairs

 */

static uint32_t IPPairHashRowTimeout(IPPairHashRow *hb, IPPair *h, SCTime_t ts)

{

    uint32_t cnt = 0;

    do {

        if (SCMutexTrylock(&h->m) != 0) {

            h = h->hprev;

            continue;

        }

        IPPair *next_ippair = h->hprev;

        /* check if the ippair is fully timed out and

         * ready to be discarded. */

        if (IPPairTimedOut(h, ts) == 1) {

            /* remove from the hash */

            if (h->hprev != NULL)

                h->hprev->hnext = h->hnext;

            if (h->hnext != NULL)

                h->hnext->hprev = h->hprev;

            if (hb->head == h)

                hb->head = h->hnext;

            if (hb->tail == h)

                hb->tail = h->hprev;

            h->hnext = NULL;

            h->hprev = NULL;

            IPPairClearMemory (h);

            /* no one is referring to this ippair, use_cnt 0, removed from hash

             * so we can unlock it and move it back to the spare queue. */

            SCMutexUnlock(&h->m);

            /* move to spare list */

            IPPairMoveToSpare(h);

            cnt++;

        } else {

            SCMutexUnlock(&h->m);

        }

        h = next_ippair;

    } while (h != NULL);

    return cnt;

}

/**

 *  \brief time out ippairs from the hash

 *

 *  \param ts timestamp

 *

 *  \retval cnt number of timed out ippair

 */

uint32_t IPPairTimeoutHash(SCTime_t ts)

{

    uint32_t idx = 0;

    uint32_t cnt = 0;

    for (idx = 0; idx < ippair_config.hash_size; idx++) {

        IPPairHashRow *hb = &ippair_hash[idx];

        if (HRLOCK_TRYLOCK(hb) != 0)

            continue;

        /* ippair hash bucket is now locked */

        if (hb->tail == NULL) {

            HRLOCK_UNLOCK(hb);

            continue;

        }

        /* we have a ippair, or more than one */

        cnt += IPPairHashRowTimeout(hb, hb->tail, ts);

        HRLOCK_UNLOCK(hb);

    }

    return cnt;

}