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/*
* natpmp.c
*
* Copyright (C) 2022-23 - 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_NATPMP
#include "ndpi_api.h"
#include "ndpi_private.h"
#define NATPMP_PORT 5351
enum natpmp_type {
NATPMP_REQUEST_ADDRESS = 0x00,
NATPMP_REQUEST_UDP_MAPPING = 0x01,
NATPMP_REQUEST_TCP_MAPPING = 0x02,
NATPMP_RESPONSE_ADDRESS = 0x80,
NATPMP_RESPONSE_UDP_MAPPING = 0x81,
NATPMP_RESPONSE_TCP_MAPPING = 0x82
};
static int ndpi_search_natpmp_extra(struct ndpi_detection_module_struct *ndpi_struct,
struct ndpi_flow_struct *flow);
static void ndpi_int_natpmp_add_connection(struct ndpi_detection_module_struct * const ndpi_struct,
struct ndpi_flow_struct * const flow)
{
NDPI_LOG_INFO(ndpi_struct, "found nat-pmp\n");
ndpi_set_detected_protocol(ndpi_struct, flow,
NDPI_PROTOCOL_NATPMP,
NDPI_PROTOCOL_UNKNOWN,
NDPI_CONFIDENCE_DPI);
if (flow->extra_packets_func == NULL)
{
flow->max_extra_packets_to_check = 5;
flow->extra_packets_func = ndpi_search_natpmp_extra;
}
}
static void natpmp_disable_extra_dissection(struct ndpi_flow_struct * const flow)
{
flow->max_extra_packets_to_check = 0;
flow->extra_packets_func = NULL;
}
static int natpmp_is_common_header(struct ndpi_packet_struct const * const packet)
{
return packet->payload_packet_len >= 2 && packet->payload[0] == 0x00 /* Protocol version: 0x00 */;
}
static int natpmp_is_valid(struct ndpi_packet_struct const * const packet, enum natpmp_type * const natpmp_type)
{
if (natpmp_is_common_header(packet) == 0)
{
return 0;
}
*natpmp_type = packet->payload[1];
switch (*natpmp_type)
{
case NATPMP_REQUEST_ADDRESS:
if (packet->payload_packet_len != 2)
{
return 0;
}
break;
case NATPMP_REQUEST_UDP_MAPPING:
case NATPMP_REQUEST_TCP_MAPPING:
if (packet->payload_packet_len != 12 || get_u_int16_t(packet->payload, 2) != 0x0000)
{
return 0;
}
break;
case NATPMP_RESPONSE_ADDRESS:
case NATPMP_RESPONSE_UDP_MAPPING:
case NATPMP_RESPONSE_TCP_MAPPING:
if ((*natpmp_type == NATPMP_RESPONSE_ADDRESS && packet->payload_packet_len != 12) ||
(*natpmp_type != NATPMP_RESPONSE_ADDRESS && packet->payload_packet_len != 16))
{
return 0;
}
{
u_int16_t result_code = ntohs(get_u_int16_t(packet->payload, 2));
if (result_code > 5)
{
return 0;
}
}
break;
default:
return 0;
}
return 1;
}
static int ndpi_search_natpmp_extra(struct ndpi_detection_module_struct *ndpi_struct,
struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;
enum natpmp_type natpmp_type;
if (natpmp_is_valid(packet, &natpmp_type) == 0)
{
ndpi_set_risk(ndpi_struct, flow, NDPI_MALFORMED_PACKET, "Invalid NATPMP Header");
return 0;
}
switch (natpmp_type)
{
case NATPMP_REQUEST_ADDRESS:
return 1; // Nothing to do here.
case NATPMP_REQUEST_UDP_MAPPING:
case NATPMP_REQUEST_TCP_MAPPING:
flow->protos.natpmp.internal_port = ntohs(get_u_int16_t(packet->payload, 4));
flow->protos.natpmp.external_port = ntohs(get_u_int16_t(packet->payload, 6));
if (flow->protos.natpmp.internal_port == 0)
{
ndpi_set_risk(ndpi_struct, flow, NDPI_MALFORMED_PACKET, "Request Port Mapping: Internal port must not 0");
}
break;
case NATPMP_RESPONSE_ADDRESS:
flow->protos.natpmp.result_code = ntohs(get_u_int16_t(packet->payload, 2));
flow->protos.natpmp.external_address.ipv4 = get_u_int32_t(packet->payload, 8);
if (flow->protos.natpmp.result_code != 0 && flow->protos.natpmp.external_address.ipv4 != 0)
{
ndpi_set_risk(ndpi_struct, flow, NDPI_MALFORMED_PACKET, "Address Response: Result code indicates an error, but External IPv4 Address is set");
}
break;
case NATPMP_RESPONSE_UDP_MAPPING:
case NATPMP_RESPONSE_TCP_MAPPING:
{
flow->protos.natpmp.internal_port = ntohs(get_u_int16_t(packet->payload, 8));
flow->protos.natpmp.external_port = ntohs(get_u_int16_t(packet->payload, 10));
if (flow->protos.natpmp.internal_port == 0 || flow->protos.natpmp.external_port == 0)
{
ndpi_set_risk(ndpi_struct, flow, NDPI_MALFORMED_PACKET, "Port Mapping Response: Internal/External port must not 0");
}
break;
}
}
return 1;
}
static void ndpi_search_natpmp(struct ndpi_detection_module_struct *ndpi_struct,
struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;
enum natpmp_type natpmp_type;
NDPI_LOG_DBG(ndpi_struct, "search nat-pmp\n");
if (natpmp_is_valid(packet, &natpmp_type) == 0)
{
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
if ((flow->packet_counter > 2 && natpmp_type != NATPMP_REQUEST_ADDRESS) ||
ntohs(packet->udp->source) == NATPMP_PORT || ntohs(packet->udp->dest) == NATPMP_PORT)
{
ndpi_int_natpmp_add_connection(ndpi_struct, flow);
if (ndpi_search_natpmp_extra(ndpi_struct, flow) == 0)
{
natpmp_disable_extra_dissection(flow);
}
}
}
void init_natpmp_dissector(struct ndpi_detection_module_struct *ndpi_struct,
u_int32_t *id)
{
ndpi_set_bitmask_protocol_detection("NAT-PMP", ndpi_struct, *id,
NDPI_PROTOCOL_NATPMP,
ndpi_search_natpmp,
NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,
SAVE_DETECTION_BITMASK_AS_UNKNOWN,
ADD_TO_DETECTION_BITMASK
);
*id += 1;
}
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