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/*
* whatsapp.c
*
* Copyright (C) 2018 - 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_WHATSAPP
#include "ndpi_api.h"
#include "ndpi_private.h"
#define WA_SEQ(seq) { .sequence_size = NDPI_ARRAY_LENGTH(seq) - 1 /* '\0' */, \
.sequence = seq }
#define GET_SEQ_SIZE(id) (whatsapp_sequences[id].sequence_size)
#define GET_SEQ(id) (whatsapp_sequences[id].sequence)
struct whatsapp_sequence {
size_t const sequence_size;
char const * const sequence;
};
enum whatsapp_sequence_id {
WA_SEQ_NEW = 0,
WA_SEQ_OLD,
WA_SEQ_VERY_OLD,
WA_SEQ_COUNT
};
static const struct whatsapp_sequence whatsapp_sequences[WA_SEQ_COUNT] = {
WA_SEQ("\x45\x44\x00\x01\x00\x00\x04\x08"),
WA_SEQ("\x45\x44\x00\x01\x00\x00\x02\x08"),
WA_SEQ("\x57\x41\x01\x05")
};
static void ndpi_int_whatsapp_add_connection(struct ndpi_detection_module_struct * ndpi_struct,
struct ndpi_flow_struct * flow)
{
NDPI_LOG_INFO(ndpi_struct, "found WhatsApp\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_WHATSAPP,
NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
}
static int ndpi_int_match_whatsapp_sequence(struct ndpi_detection_module_struct * ndpi_struct,
struct ndpi_flow_struct * flow,
enum whatsapp_sequence_id seq_id)
{
struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;
if (flow->l4.tcp.wa_matched_so_far < GET_SEQ_SIZE(seq_id))
{
size_t match_len = GET_SEQ_SIZE(seq_id) - flow->l4.tcp.wa_matched_so_far;
if (packet->payload_packet_len < match_len)
{
match_len = packet->payload_packet_len;
}
if (memcmp(packet->payload, &GET_SEQ(seq_id)[flow->l4.tcp.wa_matched_so_far],
match_len) == 0)
{
flow->l4.tcp.wa_matched_so_far += match_len;
if (flow->l4.tcp.wa_matched_so_far == GET_SEQ_SIZE(seq_id))
{
ndpi_int_whatsapp_add_connection(ndpi_struct, flow);
}
return 0;
}
}
return 1;
}
static void ndpi_search_whatsapp(struct ndpi_detection_module_struct *ndpi_struct,
struct ndpi_flow_struct *flow) {
struct ndpi_packet_struct *packet = &ndpi_struct->packet;
NDPI_LOG_DBG(ndpi_struct, "search WhatsApp\n");
if (flow->packet_counter > 3)
{
NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);
return;
}
/*
* This is a very old sequence (2015?) but we still have it in our unit tests.
* Try to detect it, without too much effort...
*/
if (flow->l4.tcp.wa_matched_so_far == 0 &&
packet->payload_packet_len > GET_SEQ_SIZE(WA_SEQ_VERY_OLD) &&
memcmp(packet->payload, GET_SEQ(WA_SEQ_VERY_OLD), GET_SEQ_SIZE(WA_SEQ_VERY_OLD)) == 0)
{
NDPI_LOG_INFO(ndpi_struct, "found WhatsApp (old sequence)\n");
ndpi_int_whatsapp_add_connection(ndpi_struct, flow);
return;
}
if (ndpi_int_match_whatsapp_sequence(ndpi_struct, flow, WA_SEQ_NEW) == 0 ||
ndpi_int_match_whatsapp_sequence(ndpi_struct, flow, WA_SEQ_OLD) == 0)
{
return;
}
NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);
}
void init_whatsapp_dissector(struct ndpi_detection_module_struct *ndpi_struct)
{
register_dissector("WhatsApp", ndpi_struct,
ndpi_search_whatsapp,
NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
1, NDPI_PROTOCOL_WHATSAPP);
}
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