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/*
* h323.c
*
* Copyright (C) 2015-20 ntop.org
* Copyright (C) 2013 Remy Mudingay <mudingay@ill.fr>
*
* 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_H323
#include "ndpi_api.h"
struct tpkt {
u_int8_t version, reserved;
u_int16_t len;
};
void ndpi_search_h323(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct *packet = &ndpi_struct->packet;
u_int16_t dport = 0, sport = 0;
NDPI_LOG_DBG(ndpi_struct, "search H323\n");
/*
The TPKT protocol is used by ISO 8072 (on port 102)
and H.323. So this check below is to avoid ambiguities
*/
if((packet->tcp != NULL) && (packet->tcp->dest != ntohs(102))) {
NDPI_LOG_DBG2(ndpi_struct, "calculated dport over tcp\n");
/* H323 */
if(packet->payload_packet_len > 5
&& (packet->payload[0] == 0x03)
&& (packet->payload[1] == 0x00)) {
struct tpkt *t = (struct tpkt*)packet->payload;
u_int16_t len = ntohs(t->len);
if(packet->payload_packet_len == len) {
/*
We need to check if this packet is in reality
a RDP (Remote Desktop) packet encapsulated on TPTK
*/
if(packet->payload[4] == (packet->payload_packet_len - sizeof(struct tpkt) - 1)) {
/* ISO 8073/X.224 */
if((packet->payload[5] == 0xE0 /* CC Connect Request */)
|| (packet->payload[5] == 0xD0 /* CC Connect Confirm */)) {
NDPI_LOG_INFO(ndpi_struct, "found RDP\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_RDP, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
return;
}
}
flow->l4.tcp.h323_valid_packets++;
if(flow->l4.tcp.h323_valid_packets >= 2) {
NDPI_LOG_INFO(ndpi_struct, "found H323 broadcast\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_H323, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
}
} else {
/* This is not H.323 */
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
}
} else if(packet->udp != NULL) {
sport = ntohs(packet->udp->source), dport = ntohs(packet->udp->dest);
NDPI_LOG_DBG2(ndpi_struct, "calculated dport over udp\n");
if(packet->payload_packet_len >= 6 && packet->payload[0] == 0x80 && packet->payload[1] == 0x08 &&
(packet->payload[2] == 0xe7 || packet->payload[2] == 0x26) &&
packet->payload[4] == 0x00 && packet->payload[5] == 0x00)
{
NDPI_LOG_INFO(ndpi_struct, "found H323 broadcast\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_H323, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
return;
}
/* H323 */
if(sport == 1719 || dport == 1719) {
if((packet->payload_packet_len > 5)
&& (packet->payload[0] == 0x16)
&& (packet->payload[1] == 0x80)
&& (packet->payload[4] == 0x06)
&& (packet->payload[5] == 0x00)) {
NDPI_LOG_INFO(ndpi_struct, "found H323 broadcast\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_H323, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
return;
} else if(packet->payload_packet_len >= 20 && packet->payload_packet_len <= 117) {
NDPI_LOG_INFO(ndpi_struct, "found H323 broadcast\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_H323, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
return;
} else {
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
}
}
if(flow->packet_counter > 5)
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}
void init_h323_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
ndpi_set_bitmask_protocol_detection("H323", ndpi_struct, detection_bitmask, *id,
NDPI_PROTOCOL_H323,
ndpi_search_h323,
NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP_WITH_PAYLOAD,
SAVE_DETECTION_BITMASK_AS_UNKNOWN,
ADD_TO_DETECTION_BITMASK);
*id += 1;
}
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