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/* Copyright (C) 2020-2021 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.
*/
/**
* \ingroup decode
*
* @{
*/
/**
* \file
*
* \author Victor Julien <victor@inliniac.net>
*
* Decodes ERSPAN Types I and II
*/
#include "suricata-common.h"
#include "suricata.h"
#include "decode.h"
#include "decode-events.h"
#include "decode-erspan.h"
#include "util-validate.h"
#include "util-unittest.h"
#include "util-debug.h"
/**
* \brief Functions to decode ERSPAN Type I and II packets
*/
/*
* \brief ERSPAN Type I was configurable in 5.0.x but is no longer configurable.
*
* Issue a warning if a configuration setting is found.
*/
void DecodeERSPANConfig(void)
{
int enabled = 0;
if (ConfGetBool("decoder.erspan.typeI.enabled", &enabled) == 1) {
SCLogWarning("ERSPAN Type I is no longer configurable and it is always"
" enabled; ignoring configuration setting.");
}
}
/**
* \brief ERSPAN Type I
*/
int DecodeERSPANTypeI(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p,
const uint8_t *pkt, uint32_t len)
{
StatsIncr(tv, dtv->counter_erspan);
return DecodeEthernet(tv, dtv, p, pkt, len);
}
/**
* \brief ERSPAN Type II
*/
int DecodeERSPAN(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, const uint8_t *pkt, uint32_t len)
{
DEBUG_VALIDATE_BUG_ON(pkt == NULL);
StatsIncr(tv, dtv->counter_erspan);
if (len < sizeof(ErspanHdr)) {
ENGINE_SET_EVENT(p,ERSPAN_HEADER_TOO_SMALL);
return TM_ECODE_FAILED;
}
if (!PacketIncreaseCheckLayers(p)) {
return TM_ECODE_FAILED;
}
const ErspanHdr *ehdr = (const ErspanHdr *)pkt;
uint16_t version = SCNtohs(ehdr->ver_vlan) >> 12;
uint16_t vlan_id = SCNtohs(ehdr->ver_vlan) & 0x0fff;
SCLogDebug("ERSPAN: version %u vlan %u", version, vlan_id);
/* only v1 is tested at this time */
if (version != 1) {
ENGINE_SET_EVENT(p,ERSPAN_UNSUPPORTED_VERSION);
return TM_ECODE_FAILED;
}
if (vlan_id > 0) {
if (p->vlan_idx > VLAN_MAX_LAYER_IDX) {
ENGINE_SET_EVENT(p,ERSPAN_TOO_MANY_VLAN_LAYERS);
return TM_ECODE_FAILED;
}
p->vlan_id[p->vlan_idx] = vlan_id;
p->vlan_idx++;
}
return DecodeEthernet(tv, dtv, p, pkt + sizeof(ErspanHdr), len - sizeof(ErspanHdr));
}
/**
* @}
*/
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