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/*
* s7comm.c
*
* Copyright (C) 2023 - ntop.org
* Copyright (C) 2023 - V.G <jacendi@protonmail.com>
*
* This file is part of nDPI, an open source deep packet inspection
* library based on the OpenDPI and PACE technology by ipoque GmbH
*
* 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_S7COMM
#include "ndpi_api.h"
#include "ndpi_private.h"
#define TPKT_PORT 102
#define S7COMM_MAGIC_BYTE 0x32
#define S7COMM_PLUS_MAGIC_BYTE 0x72
static void ndpi_search_s7comm(struct ndpi_detection_module_struct *ndpi_struct,
struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;
NDPI_LOG_DBG(ndpi_struct, "search S7comm\n");
if (packet->tcp) {
u_int16_t sport = ntohs(packet->tcp->source);
u_int16_t dport = ntohs(packet->tcp->dest);
/* S7Comm uses a default TPKT port 102 */
if (((sport == TPKT_PORT) || (dport == TPKT_PORT)) &&
(packet->payload_packet_len > 17)) /* TPKT+COTP+S7Comm header lengths */
{
if ((packet->payload[0] == 0x03) && (packet->payload[1] == 0x00) &&
(ntohs(get_u_int16_t(packet->payload, 2)) == packet->payload_packet_len))
{
if (packet->payload[7] == S7COMM_PLUS_MAGIC_BYTE) {
const u_int16_t trail_byte_offset = packet->payload_packet_len - 4;
if (packet->payload[trail_byte_offset] == S7COMM_PLUS_MAGIC_BYTE)
{
NDPI_LOG_INFO(ndpi_struct, "found S7CommPlus\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_S7COMM_PLUS,
NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
return;
}
} else if (packet->payload[7] == S7COMM_MAGIC_BYTE) {
if (((packet->payload[8] <= 0x03) || (packet->payload[8] == 0x07)) &&
(get_u_int16_t(packet->payload, 9) == 0))
{
NDPI_LOG_INFO(ndpi_struct, "found S7Comm\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_S7COMM,
NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
return;
}
}
return;
}
}
}
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}
void init_s7comm_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id)
{
ndpi_set_bitmask_protocol_detection("S7Comm", ndpi_struct, *id,
NDPI_PROTOCOL_S7COMM,
ndpi_search_s7comm,
NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
SAVE_DETECTION_BITMASK_AS_UNKNOWN,
ADD_TO_DETECTION_BITMASK);
*id += 1;
}
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