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/*
* bacnet.c
*
* Building Automation and Control Network
*
* Copyright (C) 2023 - ntop.org
*
* nDPI is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* nDPI 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with nDPI. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "ndpi_protocol_ids.h"
#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_BACNET
#include "ndpi_api.h"
#include "ndpi_private.h"
// BVLC (BACnet Virtual Link Control) Annex is part of BVLL (BACnet Virtual Link Layer).
// See: https://www.ashrae.org/file%20library/technical%20resources/standards%20and%20guidelines/standards%20addenda/135-1995_addendum-a.pdf
PACK_ON
struct bvlc_header {
uint8_t type;
uint8_t function;
uint16_t length;
} PACK_OFF;
static void ndpi_int_bacnet_add_connection(struct ndpi_detection_module_struct * const ndpi_struct,
struct ndpi_flow_struct * const flow)
{
NDPI_LOG_INFO(ndpi_struct, "found BACnet\n");
ndpi_set_detected_protocol(ndpi_struct, flow,
NDPI_PROTOCOL_BACNET,
NDPI_PROTOCOL_UNKNOWN,
NDPI_CONFIDENCE_DPI);
}
/* ***************************************************** */
static void ndpi_search_bacnet(struct ndpi_detection_module_struct *ndpi_struct,
struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;
struct bvlc_header const * const bvlc = (struct bvlc_header *)&packet->payload[0];
NDPI_LOG_DBG(ndpi_struct, "search BACnet\n");
if (packet->payload_packet_len < sizeof(*bvlc))
{
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
if (bvlc->type != 0x81)
{
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
if (bvlc->function > 0x0b)
{
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
if (ntohs(bvlc->length) != packet->payload_packet_len)
{
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
ndpi_int_bacnet_add_connection(ndpi_struct, flow);
}
/* ***************************************************** */
void init_bacnet_dissector(struct ndpi_detection_module_struct *ndpi_struct,
u_int32_t *id)
{
ndpi_set_bitmask_protocol_detection("BACnet", ndpi_struct, *id,
NDPI_PROTOCOL_BACNET,
ndpi_search_bacnet,
NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,
SAVE_DETECTION_BITMASK_AS_UNKNOWN,
ADD_TO_DETECTION_BITMASK
);
*id += 1;
}
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