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/*
* socks5.c
*
* Copyright (C) 2014 Tomasz Bujlow <tomasz@skatnet.dk>
*
* The signature is based on the Libprotoident library.
*
* 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_api.h"
#ifdef NDPI_PROTOCOL_SOCKS5
static void ndpi_int_socks5_add_connection(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
ndpi_int_add_connection(ndpi_struct, flow, NDPI_PROTOCOL_SOCKS5, NDPI_REAL_PROTOCOL);
}
static void ndpi_check_socks5(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct *packet = &flow->packet;
u_int32_t payload_len = packet->payload_packet_len;
/* Break after 20 packets. */
if (flow->packet_counter > 20) {
NDPI_LOG(NDPI_PROTOCOL_SOCKS5, ndpi_struct, NDPI_LOG_DEBUG, "Exclude SOCKS5.\n");
NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_SOCKS5);
return;
}
/* Check if we so far detected the protocol in the request or not. */
if (flow->socks5_stage == 0) {
NDPI_LOG(NDPI_PROTOCOL_SOCKS5, ndpi_struct, NDPI_LOG_DEBUG, "SOCKS5 stage 0: \n");
if ((payload_len == 3) && (packet->payload[0] == 0x05) && (packet->payload[1] == 0x01) && (packet->payload[2] == 0x00)) {
NDPI_LOG(NDPI_PROTOCOL_SOCKS5, ndpi_struct, NDPI_LOG_DEBUG, "Possible SOCKS5 request detected, we will look further for the response...\n");
/* Encode the direction of the packet in the stage, so we will know when we need to look for the response packet. */
flow->socks5_stage = packet->packet_direction + 1;
}
} else {
NDPI_LOG(NDPI_PROTOCOL_SOCKS5, ndpi_struct, NDPI_LOG_DEBUG, "SOCKS5 stage %u: \n", flow->socks5_stage);
/* At first check, if this is for sure a response packet (in another direction. If not, do nothing now and return. */
if ((flow->socks5_stage - packet->packet_direction) == 1) {
return;
}
/* This is a packet in another direction. Check if we find the proper response. */
if ((payload_len == 0) || ((payload_len == 2) && (packet->payload[0] == 0x05) && (packet->payload[1] == 0x00))) {
NDPI_LOG(NDPI_PROTOCOL_SOCKS5, ndpi_struct, NDPI_LOG_DEBUG, "Found SOCKS5.\n");
ndpi_int_socks5_add_connection(ndpi_struct, flow);
} else {
NDPI_LOG(NDPI_PROTOCOL_SOCKS5, ndpi_struct, NDPI_LOG_DEBUG, "The reply did not seem to belong to SOCKS5, resetting the stage to 0...\n");
flow->socks5_stage = 0;
}
}
}
void ndpi_search_socks5(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct *packet = &flow->packet;
NDPI_LOG(NDPI_PROTOCOL_SOCKS5, ndpi_struct, NDPI_LOG_DEBUG, "SOCKS5 detection...\n");
/* skip marked packets */
if (packet->detected_protocol_stack[0] != NDPI_PROTOCOL_SOCKS5) {
if (packet->tcp_retransmission == 0) {
ndpi_check_socks5(ndpi_struct, flow);
}
}
}
#endif
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