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/*
* whatsapp.c
*
* Copyright (C) 2018 - ntop.org
*
* nDPI is free software: you can zmqtribute 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"
static void ndpi_whatsapp_dissect_extra(struct ndpi_flow_struct * const flow,
u_int8_t const * const payload,
u_int32_t payload_len)
{
size_t offset = 18;
while (offset + 1 < payload_len)
{
u_int8_t op = payload[offset];
u_int8_t len = payload[offset + 1];
offset += 2;
if (offset + len >= payload_len)
{
break;
}
switch (op)
{
case 0x28:
case 0x08:
break;
case 0x12:
flow->http.user_agent = ndpi_malloc(len + 1);
if (flow->http.user_agent != NULL)
{
memcpy(flow->http.user_agent, &payload[offset], len);
flow->http.user_agent[len] = '\0';
}
offset += len;
break;
case 0x3a:
ndpi_hostname_sni_set(flow, &payload[offset], len);
break;
default:
offset += len;
break;
}
}
}
void ndpi_search_whatsapp(struct ndpi_detection_module_struct *ndpi_struct,
struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct *packet = &ndpi_struct->packet;
static u_int8_t whatsapp_sequence[] = {
0x45, 0x44, 0x0, 0x01, 0x0, 0x0, 0x02, 0x08,
0x0, 0x57, 0x41, 0x02, 0x0, 0x0, 0x0
};
static u_int8_t whatsapp_old_sequence[] = {
0x57, 0x41, 0x01, 0x05
};
NDPI_LOG_DBG(ndpi_struct, "search WhatsApp\n");
if (packet->payload_packet_len == 4 && ntohl(get_u_int32_t(packet->payload, 0)) == 0x45440001)
{
NDPI_LOG_INFO(ndpi_struct, "found WhatsApp preface\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_WHATSAPP, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
return;
}
if (packet->payload_packet_len >= 32 &&
ntohs(get_u_int16_t(packet->payload, 0)) == 0xc2fe &&
packet->payload[3] == 0x05 &&
ntohl(get_u_int32_t(packet->payload, 8)) == 0x00020016 &&
packet->payload[16] == 0x08)
{
NDPI_LOG_INFO(ndpi_struct, "found WhatsApp (additional info available)\n");
ndpi_whatsapp_dissect_extra(flow, packet->payload, packet->payload_packet_len);
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_WHATSAPP, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
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 > sizeof(whatsapp_old_sequence) &&
memcmp(packet->payload, whatsapp_old_sequence, sizeof(whatsapp_old_sequence)) == 0) {
NDPI_LOG_INFO(ndpi_struct, "found WhatsApp (old sequence)\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_WHATSAPP, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
return;
}
if(flow->l4.tcp.wa_matched_so_far < sizeof(whatsapp_sequence)) {
size_t match_len = sizeof(whatsapp_sequence) - flow->l4.tcp.wa_matched_so_far;
if(packet->payload_packet_len < match_len)
match_len = packet->payload_packet_len;
if(!memcmp(packet->payload, &whatsapp_sequence[flow->l4.tcp.wa_matched_so_far], match_len)) {
flow->l4.tcp.wa_matched_so_far += match_len;
if(flow->l4.tcp.wa_matched_so_far == sizeof(whatsapp_sequence)) {
NDPI_LOG_INFO(ndpi_struct, "found WhatsApp\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_WHATSAPP, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
}
return;
}
}
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}
void init_whatsapp_dissector(struct ndpi_detection_module_struct *ndpi_struct,
u_int32_t *id,
NDPI_PROTOCOL_BITMASK *detection_bitmask) {
ndpi_set_bitmask_protocol_detection("WhatsApp", ndpi_struct, detection_bitmask, *id,
NDPI_PROTOCOL_WHATSAPP,
ndpi_search_whatsapp,
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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