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/* Copyright (C) 2015-2021 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 XXX Your Name <your@email.com>
*
* Decodes XXX describe the protocol
*/
#include "suricata-common.h"
#include "suricata.h"
#include "decode.h"
#include "decode-events.h"
#include "decode-template.h"
#include "util-validate.h"
/**
* \brief Function to decode TEMPLATE packets
* \param tv thread vars
* \param dtv decoder thread vars
* \param p packet
* \param pkt raw packet data
* \param len length in bytes of pkt array
* \retval TM_ECODE_OK or TM_ECODE_FAILED on serious error
*/
int DecodeTEMPLATE(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p,
const uint8_t *pkt, uint32_t len)
{
DEBUG_VALIDATE_BUG_ON(pkt == NULL);
/* TODO add counter for your type of packet to DecodeThreadVars,
* and register it in DecodeRegisterPerfCounters */
//StatsIncr(tv, dtv->counter_template);
/* Validation: make sure that the input data is big enough to hold
* the header */
if (len < sizeof(TemplateHdr)) {
/* in case of errors, we set events. Events are defined in
* decode-events.h, and are then exposed to the detection
* engine through detect-engine-events.h */
//ENGINE_SET_EVENT(p,TEMPLATE_HEADER_TOO_SMALL);
return TM_ECODE_FAILED;
}
/* Each packet keeps a count of decoded layers
* This function increases it and returns false
* if we have too many decoded layers, such as
* ethernet/MPLS/ethernet/MPLS... which may
* lead to stack overflow by a too deep recursion
*/
if (!PacketIncreaseCheckLayers(p)) {
return TM_ECODE_FAILED;
}
/* Now we can access the header */
const TemplateHdr *hdr = (const TemplateHdr *)pkt;
/* lets assume we have UDP encapsulated */
if (hdr->proto == 17) {
/* we need to pass on the pkt and it's length minus the current
* header */
size_t hdr_len = sizeof(TemplateHdr);
/* in this example it's clear that hdr_len can't be bigger than
* 'len', but in more complex cases checking that we can't underflow
* len is very important
if (hdr_len >= len) {
ENGINE_SET_EVENT(p,TEMPLATE_MALFORMED_HDRLEN);
return TM_ECODE_FAILED;
}
*/
if (unlikely(len - hdr_len > USHRT_MAX)) {
return TM_ECODE_FAILED;
}
/* invoke the next decoder on the remainder of the data */
return DecodeUDP(tv, dtv, p, (uint8_t *)pkt + hdr_len, (uint16_t)(len - hdr_len));
} else {
//ENGINE_SET_EVENT(p,TEMPLATE_UNSUPPORTED_PROTOCOL);
return TM_ECODE_FAILED;
}
return TM_ECODE_OK;
}
/**
* @}
*/
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