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suricata/src/util-prefilter.c

133 lines
3.6 KiB
C

/* Copyright (C) 2007-2014 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>
*
* Pattern matcher utility Functions
*/
#include "suricata-common.h"
/**
* \brief Setup a pmq
*
* \param pmq Pattern matcher queue to be initialized
*
* \retval -1 error
* \retval 0 ok
*/
int PmqSetup(PrefilterRuleStore *pmq)
{
SCEnter();
if (pmq == NULL) {
SCReturnInt(-1);
}
memset(pmq, 0, sizeof(PrefilterRuleStore));
pmq->rule_id_array_size = 128; /* Initial size, TODO: Make configure option. */
pmq->rule_id_array_cnt = 0;
size_t bytes = pmq->rule_id_array_size * sizeof(SigIntId);
pmq->rule_id_array = (SigIntId*)SCMalloc(bytes);
if (pmq->rule_id_array == NULL) {
pmq->rule_id_array_size = 0;
SCReturnInt(-1);
}
// Don't need to zero memory since it is always written first.
SCReturnInt(0);
}
/** \brief Add array of Signature IDs to rule ID array.
*
* Checks size of the array first
*
* \param pmq storage for match results
* \param new_size number of Signature IDs needing to be stored.
*
*/
int
PrefilterAddSidsResize(PrefilterRuleStore *pmq, uint32_t new_size)
{
/* Need to make the array bigger. Double the size needed to
* also handle the case that sids_size might still be
* larger than the old size.
*/
new_size = new_size * 2;
SigIntId *new_array = (SigIntId*)SCRealloc(pmq->rule_id_array,
new_size * sizeof(SigIntId));
if (unlikely(new_array == NULL)) {
/* Try again just big enough. */
new_size = new_size / 2;
new_array = (SigIntId*)SCRealloc(pmq->rule_id_array,
new_size * sizeof(SigIntId));
if (unlikely(new_array == NULL)) {
SCLogError(SC_ERR_MEM_ALLOC, "Failed to realloc PatternMatchQueue"
" rule ID array. Some signature ID matches lost");
return 0;
}
}
pmq->rule_id_array = new_array;
pmq->rule_id_array_size = new_size;
return new_size;
}
/** \brief Reset a Pmq for reusage. Meant to be called after a single search.
* \param pmq Pattern matcher to be reset.
* \todo memset is expensive, but we need it as we merge pmq's. We might use
* a flag so we can clear pmq's the old way if we can.
*/
void PmqReset(PrefilterRuleStore *pmq)
{
if (pmq == NULL)
return;
pmq->rule_id_array_cnt = 0;
/* TODO: Realloc the rule id array smaller at some size? */
}
/** \brief Cleanup a Pmq
* \param pmq Pattern matcher queue to be cleaned up.
*/
void PmqCleanup(PrefilterRuleStore *pmq)
{
if (pmq == NULL)
return;
if (pmq->rule_id_array != NULL) {
SCFree(pmq->rule_id_array);
pmq->rule_id_array = NULL;
}
}
/** \brief Cleanup and free a Pmq
* \param pmq Pattern matcher queue to be free'd.
*/
void PmqFree(PrefilterRuleStore *pmq)
{
if (pmq == NULL)
return;
PmqCleanup(pmq);
}