source-lib.c

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/* Copyright (C) 2023-2024 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 Angelo Mirabella <angelo.mirabella@broadcom.com>
 *
 *  LIB packet and stream decoding support
 *
 */
 
#include "suricata-common.h"
#include "source-lib.h"
#include "util-device-private.h"
 
/** \brief initialize the "Decode" module.
 *
 * \param tv                    Pointer to the per-thread structure.
 * \param initdata              Pointer to initialization context.
 * \param data                  Pointer to the initialized context.
 * \return                      Error code.
 */
static TmEcode DecodeLibThreadInit(ThreadVars *tv, const void *initdata, void **data)
{
    SCEnter();
    DecodeThreadVars *dtv = NULL;
 
    dtv = DecodeThreadVarsAlloc(tv);
 
    if (dtv == NULL)
        SCReturnInt(TM_ECODE_FAILED);
 
    DecodeRegisterPerfCounters(dtv, tv);
 
    *data = (void *)dtv;
 
    SCReturnInt(TM_ECODE_OK);
}
 
/** \brief deinitialize the "Decode" module.
 *
 * \param tv                    Pointer to the per-thread structure.
 * \param data                  Pointer to the context.
 * \return                      Error code.
 */
static TmEcode DecodeLibThreadDeinit(ThreadVars *tv, void *data)
{
    if (data != NULL)
        DecodeThreadVarsFree(tv, data);
 
    SCReturnInt(TM_ECODE_OK);
}
 
/** \brief main decoding function.
 *
 *  This method receives a packet and tries to identify layer 2 to 4 layers.
 *
 * \param tv                    Pointer to the per-thread structure.
 * \param p                     Pointer to the packet.
 * \param data                  Pointer to the context.
 * \return                      Error code.
 */
static TmEcode DecodeLib(ThreadVars *tv, Packet *p, void *data)
{
    SCEnter();
    DecodeThreadVars *dtv = (DecodeThreadVars *)data;
 
    BUG_ON(PKT_IS_PSEUDOPKT(p));
 
    /* update counters */
    DecodeUpdatePacketCounters(tv, dtv, p);
 
    /* If suri has set vlan during reading, we increase vlan counter */
    if (p->vlan_idx) {
        StatsCounterIncr(&tv->stats, dtv->counter_vlan);
    }
 
    /* call the decoder */
    DecodeLinkLayer(tv, dtv, p->datalink, p, GET_PKT_DATA(p), GET_PKT_LEN(p));
 
    PacketDecodeFinalize(tv, dtv, p);
 
    SCReturnInt(TM_ECODE_OK);
}
 
/** \brief register a "Decode" module for suricata as a library.
 *
 *  The "Decode" module is the first module invoked when processing a packet */
void TmModuleDecodeLibRegister(void)
{
    tmm_modules[TMM_DECODELIB].name = "DecodeLib";
    tmm_modules[TMM_DECODELIB].ThreadInit = DecodeLibThreadInit;
    tmm_modules[TMM_DECODELIB].Func = DecodeLib;
    tmm_modules[TMM_DECODELIB].ThreadExitPrintStats = NULL;
    tmm_modules[TMM_DECODELIB].ThreadDeinit = DecodeLibThreadDeinit;
    tmm_modules[TMM_DECODELIB].cap_flags = 0;
    tmm_modules[TMM_DECODELIB].flags = TM_FLAG_DECODE_TM;
}