mirror of
https://github.com/vel21ripn/nDPI.git
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107 lines
3.2 KiB
C
107 lines
3.2 KiB
C
/*
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* telnet.c
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*
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* Copyright (C) 2009-2011 by ipoque GmbH
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* Copyright (C) 2011-15 - ntop.org
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*
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* This file is part of nDPI, an open source deep packet inspection
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* library based on the OpenDPI and PACE technology by ipoque GmbH
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*
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* nDPI is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* nDPI is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with nDPI. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "ndpi_protocols.h"
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#ifdef NDPI_PROTOCOL_TELNET
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static void ndpi_int_telnet_add_connection(struct ndpi_detection_module_struct
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*ndpi_struct, struct ndpi_flow_struct *flow)
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{
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ndpi_int_add_connection(ndpi_struct, flow, NDPI_PROTOCOL_TELNET, NDPI_REAL_PROTOCOL);
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}
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#if !defined(WIN32)
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static inline
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#else
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__forceinline static
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#endif
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u_int8_t search_iac(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
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{
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struct ndpi_packet_struct *packet = &flow->packet;
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u_int16_t a;
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if (packet->payload_packet_len < 3) {
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return 0;
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}
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if (!(packet->payload[0] == 0xff
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&& packet->payload[1] > 0xf9 && packet->payload[1] != 0xff && packet->payload[2] < 0x28)) {
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return 0;
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}
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a = 3;
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while (a < packet->payload_packet_len - 2) {
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// commands start with a 0xff byte followed by a command byte >= 0xf0 and < 0xff
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// command bytes 0xfb to 0xfe are followed by an option byte <= 0x28
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if (!(packet->payload[a] != 0xff ||
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(packet->payload[a] == 0xff && (packet->payload[a + 1] >= 0xf0) && (packet->payload[a + 1] <= 0xfa)) ||
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(packet->payload[a] == 0xff && (packet->payload[a + 1] >= 0xfb) && (packet->payload[a + 1] != 0xff)
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&& (packet->payload[a + 2] <= 0x28)))) {
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return 0;
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}
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a++;
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}
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return 1;
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}
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/* this detection also works asymmetrically */
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void ndpi_search_telnet_tcp(struct ndpi_detection_module_struct
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*ndpi_struct, struct ndpi_flow_struct *flow)
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{
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// struct ndpi_packet_struct *packet = &flow->packet;
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// struct ndpi_id_struct *src=ndpi_struct->src;
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// struct ndpi_id_struct *dst=ndpi_struct->dst;
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NDPI_LOG(NDPI_PROTOCOL_TELNET, ndpi_struct, NDPI_LOG_DEBUG, "search telnet.\n");
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if (search_iac(ndpi_struct, flow) == 1) {
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if (flow->l4.tcp.telnet_stage == 2) {
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NDPI_LOG(NDPI_PROTOCOL_TELNET, ndpi_struct, NDPI_LOG_DEBUG, "telnet identified.\n");
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ndpi_int_telnet_add_connection(ndpi_struct, flow);
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return;
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}
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flow->l4.tcp.telnet_stage++;
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NDPI_LOG(NDPI_PROTOCOL_TELNET, ndpi_struct, NDPI_LOG_DEBUG, "telnet stage %u.\n", flow->l4.tcp.telnet_stage);
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return;
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}
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if ((flow->packet_counter < 12 && flow->l4.tcp.telnet_stage > 0) || flow->packet_counter < 6) {
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return;
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} else {
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NDPI_LOG(NDPI_PROTOCOL_TELNET, ndpi_struct, NDPI_LOG_DEBUG, "telnet excluded.\n");
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NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_TELNET);
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}
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return;
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}
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#endif
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