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/* 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 "decode.h"
#include "defrag.h"
#include "defrag-hash.h"
#include "defrag-timeout.h"
/** \internal
* \brief See if we can really discard this tracker. Check use_cnt reference.
*
* \param dt tracker
* \param ts timestamp
*
* \retval 0 not timed out just yet
* \retval 1 fully timed out, lets kill it
*/
static int DefragTrackerTimedOut(DefragTracker *dt, SCTime_t ts)
{
/** never prune a trackers that is used by a packet
* we are currently processing in one of the threads */
if (SC_ATOMIC_GET(dt->use_cnt) > 0) {
return 0;
}
/* retain if remove is not set and not timed out */
if (!dt->remove && SCTIME_CMP_GT(dt->timeout, ts))
return 0;
return 1;
}
/**
* \internal
*
* \brief check all trackers in a hash row for timing out
*
* \param hb tracker hash row *LOCKED*
* \param dt last tracker in the hash row
* \param ts timestamp
*
* \retval cnt timed out tracker
*/
static uint32_t DefragTrackerHashRowTimeout(
DefragTrackerHashRow *hb, DefragTracker *dt, SCTime_t ts)
{
uint32_t cnt = 0;
do {
if (SCMutexTrylock(&dt->lock) != 0) {
dt = dt->hprev;
continue;
}
DefragTracker *next_dt = dt->hprev;
/* check if the tracker is fully timed out and
* ready to be discarded. */
if (DefragTrackerTimedOut(dt, ts) == 1) {
/* remove from the hash */
if (dt->hprev != NULL)
dt->hprev->hnext = dt->hnext;
if (dt->hnext != NULL)
dt->hnext->hprev = dt->hprev;
if (hb->head == dt)
hb->head = dt->hnext;
if (hb->tail == dt)
hb->tail = dt->hprev;
dt->hnext = NULL;
dt->hprev = NULL;
DefragTrackerClearMemory(dt);
/* no one is referring to this tracker, use_cnt 0, removed from hash
* so we can unlock it and move it back to the spare queue. */
SCMutexUnlock(&dt->lock);
/* move to spare list */
DefragTrackerMoveToSpare(dt);
cnt++;
} else {
SCMutexUnlock(&dt->lock);
}
dt = next_dt;
} while (dt != NULL);
return cnt;
}
/**
* \brief time out tracker from the hash
*
* \param ts timestamp
*
* \retval cnt number of timed out tracker
*/
uint32_t DefragTimeoutHash(SCTime_t ts)
{
uint32_t idx = 0;
uint32_t cnt = 0;
for (idx = 0; idx < defrag_config.hash_size; idx++) {
DefragTrackerHashRow *hb = &defragtracker_hash[idx];
if (DRLOCK_TRYLOCK(hb) != 0)
continue;
/* defrag hash bucket is now locked */
if (hb->tail == NULL) {
DRLOCK_UNLOCK(hb);
continue;
}
/* we have a tracker, or more than one */
cnt += DefragTrackerHashRowTimeout(hb, hb->tail, ts);
DRLOCK_UNLOCK(hb);
}
return cnt;
}
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