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/* Copyright (C) 2007-2010 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>
*
* Generic variable name utility functions
*/
#include "suricata-common.h"
#include "detect.h"
#include "util-hashlist.h"
/** \brief Name2idx mapping structure for flowbits, flowvars and pktvars. */
typedef struct VariableName_ {
char *name;
uint8_t type; /* flowbit, pktvar, etc */
uint8_t flags;
uint16_t idx;
} VariableName;
static uint32_t VariableNameHash(HashListTable *ht, void *buf, uint16_t buflen)
{
VariableName *fn = (VariableName *)buf;
uint32_t hash = strlen(fn->name) + fn->type;
uint16_t u;
for (u = 0; u < buflen; u++) {
hash += fn->name[u];
}
return hash;
}
static char VariableNameCompare(void *buf1, uint16_t len1, void *buf2, uint16_t len2)
{
VariableName *fn1 = (VariableName *)buf1;
VariableName *fn2 = (VariableName *)buf2;
if (fn1->type != fn2->type)
return 0;
if (strcmp(fn1->name,fn2->name) == 0)
return 1;
return 0;
}
static uint32_t VariableIdxHash(HashListTable *ht, void *buf, uint16_t buflen)
{
VariableName *fn = (VariableName *)buf;
uint32_t hash = fn->idx + fn->type;
return hash;
}
static char VariableIdxCompare(void *buf1, uint16_t len1, void *buf2, uint16_t len2)
{
VariableName *fn1 = (VariableName *)buf1;
VariableName *fn2 = (VariableName *)buf2;
if (fn1->type != fn2->type)
return 0;
if (fn1->idx == fn2->idx)
return 1;
return 0;
}
static void VariableNameFree(void *data)
{
VariableName *fn = (VariableName *)data;
if (fn == NULL)
return;
if (fn->name != NULL) {
SCFree(fn->name);
fn->name = NULL;
}
SCFree(fn);
}
/** \brief Initialize the Name idx hash.
* \param de_ctx Ptr to the detection engine ctx.
* \retval -1 in case of error
* \retval 0 in case of success
*/
int VariableNameInitHash(DetectEngineCtx *de_ctx)
{
de_ctx->variable_names = HashListTableInit(4096, VariableNameHash, VariableNameCompare, VariableNameFree);
if (de_ctx->variable_names == NULL)
return -1;
de_ctx->variable_idxs = HashListTableInit(4096, VariableIdxHash, VariableIdxCompare, NULL);
if (de_ctx->variable_idxs == NULL)
return -1;
de_ctx->variable_names_idx = 0;
return 0;
}
void VariableNameFreeHash(DetectEngineCtx *de_ctx)
{
if (de_ctx->variable_names != NULL) {
HashListTableFree(de_ctx->variable_names);
HashListTableFree(de_ctx->variable_idxs);
de_ctx->variable_names = NULL;
de_ctx->variable_idxs = NULL;
}
return;
}
/** \brief Get a name idx for a name. If the name is already used reuse the idx.
* \param name nul terminated string with the name
* \param type variable type
* \retval 0 in case of error
* \retval idx the idx or 0
*/
uint16_t VariableNameGetIdx(DetectEngineCtx *de_ctx, char *name, enum VarTypes type)
{
uint16_t idx = 0;
VariableName *fn = SCMalloc(sizeof(VariableName));
if (unlikely(fn == NULL))
goto error;
memset(fn, 0, sizeof(VariableName));
fn->type = type;
fn->name = SCStrdup(name);
if (fn->name == NULL)
goto error;
VariableName *lookup_fn = (VariableName *)HashListTableLookup(de_ctx->variable_names, (void *)fn, 0);
if (lookup_fn == NULL) {
de_ctx->variable_names_idx++;
idx = fn->idx = de_ctx->variable_names_idx;
HashListTableAdd(de_ctx->variable_names, (void *)fn, 0);
HashListTableAdd(de_ctx->variable_idxs, (void *)fn, 0);
} else {
idx = lookup_fn->idx;
VariableNameFree(fn);
}
return idx;
error:
VariableNameFree(fn);
return 0;
}
/** \brief Get a name from the idx.
* \param idx index of the variable whose name is to be fetched
* \param type variable type
* \retval NULL in case of error
* \retval name of the variable if successful.
*/
char *VariableIdxGetName(DetectEngineCtx *de_ctx, uint16_t idx, enum VarTypes type)
{
VariableName *fn = SCMalloc(sizeof(VariableName));
if (unlikely(fn == NULL))
goto error;
char *name = NULL;
memset(fn, 0, sizeof(VariableName));
fn->type = type;
fn->idx = idx;
VariableName *lookup_fn = (VariableName *)HashListTableLookup(de_ctx->variable_idxs, (void *)fn, 0);
if (lookup_fn != NULL) {
name = SCStrdup(lookup_fn->name);
if (unlikely(name == NULL))
goto error;
VariableNameFree(fn);
} else {
goto error;
}
return name;
error:
VariableNameFree(fn);
return NULL;
}
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