/* 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 "host.h"

#include "detect-engine-tag.h"

#include "detect-engine-threshold.h"

#include "host-bit.h"

#include "host-timeout.h"

#include "reputation.h"

uint32_t HostGetSpareCount(void)

{

    return HostSpareQueueGetSize();

}

uint32_t HostGetActiveCount(void)

{

    return SC_ATOMIC_GET(host_counter);

}

/** \internal

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

 *

 *  \param h host

 *  \param ts timestamp

 *

 *  \retval 0 not timed out just yet

 *  \retval 1 fully timed out, lets kill it

 */

static int HostHostTimedOut(Host *h, SCTime_t ts)

{

    int busy = 0;

    /** never prune a host 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;

    }

    busy |= (h->iprep && SRepHostTimedOut(h) == 0);

    busy |= (TagHostHasTag(h) && TagTimeoutCheck(h, ts) == 0);

    busy |= (ThresholdHostHasThreshold(h) && ThresholdHostTimeoutCheck(h, ts) == 0);

    busy |= (HostHasHostBits(h) && HostBitsTimedoutCheck(h, ts) == 0);

    SCLogDebug("host %p %s", h, busy ? "still active" : "timed out");

    return !busy;

}

/**

 *  \internal

 *

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

 *

 *  \param hb host hash row *LOCKED*

 *  \param h last host in the hash row

 *  \param ts timestamp

 *

 *  \retval cnt timed out hosts

 */

static uint32_t HostHashRowTimeout(HostHashRow *hb, Host *h, SCTime_t ts)

{

    uint32_t cnt = 0;

    do {

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

            h = h->hprev;

            continue;

        }

        Host *next_host = h->hprev;

        /* check if the host is fully timed out and

         * ready to be discarded. */

        if (HostHostTimedOut(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;

            HostClearMemory (h);

            /* no one is referring to this host, 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 */

            HostMoveToSpare(h);

            cnt++;

        } else {

            SCMutexUnlock(&h->m);

        }

        h = next_host;

    } while (h != NULL);

    return cnt;

}

/**

 *  \brief time out hosts from the hash

 *

 *  \param ts timestamp

 *

 *  \retval cnt number of timed out host

 */

uint32_t HostTimeoutHash(SCTime_t ts)

{

    uint32_t idx = 0;

    uint32_t cnt = 0;

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

        HostHashRow *hb = &host_hash[idx];

        if (HRLOCK_TRYLOCK(hb) != 0)

            continue;

        /* host hash bucket is now locked */

        if (hb->tail == NULL) {

            HRLOCK_UNLOCK(hb);

            continue;

        }

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

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

        HRLOCK_UNLOCK(hb);

    }

    return cnt;

}