195 lines
5.9 KiB
C++
195 lines
5.9 KiB
C++
/*
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*
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* Copyright (c) 2011-2016 The University of Waikato, Hamilton, New Zealand.
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* All rights reserved.
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*
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* This file is part of libprotoident.
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*
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* This code has been developed by the University of Waikato WAND
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* research group. For further information please see http://www.wand.net.nz/
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*
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* libprotoident 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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* libprotoident 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 this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*
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*/
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#include <string.h>
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#include "libprotoident.h"
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#include "proto_manager.h"
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#include "proto_common.h"
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static inline bool match_rtp_payload(uint32_t payload, uint32_t len,
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uint32_t other_len) {
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/* This rule seems very weak -- maybe need to capture some known
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* RTP traffic to try and strengthen it?
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*/
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/* Be stricter about packet length when looking at one-way flows */
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if (other_len == 0) {
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if (len != 32 && len != 92 && len != 172 &&
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len != 31 && len != 24)
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return false;
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}
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if (MATCH(payload, 0x80, ANY, ANY, ANY))
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return true;
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if (MATCH(payload, 0x90, ANY, ANY, ANY))
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return true;
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if (MATCH(payload, 0x91, ANY, ANY, ANY))
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return true;
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return false;
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}
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static inline bool match_rtp_806d(uint32_t payload, uint32_t len) {
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/* Common pattern we see on our local videoconf server */
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if (len == 24 && MATCH(payload, 0x80, 0x6d, 0x00, 0x00))
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return true;
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return false;
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}
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static inline bool match_rtp_80c9(uint32_t payload, uint32_t len) {
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if (len == 94 && MATCH(payload, 0x80, 0xc9, 0x00, 0x01))
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return true;
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return false;
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}
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static inline bool match_rtcp_report(uint32_t payload, uint32_t len) {
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if (len == 16 && MATCH(payload, 0x81, 0xcd, 0x00, 0x03))
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return true;
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if (len == 20 && MATCH(payload, 0x81, 0xcd, 0x00, 0x03))
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return true;
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if (len == 32 && MATCH(payload, 0x81, 0xc9, 0x00, 0x07))
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return true;
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if (len == 36 && MATCH(payload, 0x81, 0xc9, 0x00, 0x07))
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return true;
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return false;
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}
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static inline bool match_stun_response(uint32_t payload, uint32_t len) {
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uint32_t plen = ntohl(payload) & 0xffff;
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/* Many VOIP phones use STUN for NAT traversal, so the response to
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* outgoing RTP is often a STUN packet */
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if (len - 20 == plen && MATCH(payload, 0x00, 0x01, 0x00, ANY))
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return true;
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if (len == 12 && MATCH(payload, 0x00, 0x11, 0x00, 0x00))
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return true;
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/* Facebook-specific STUN? Message type 0x003 is not defined in
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* any official STUN documentation */
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if (len == 126 && MATCH(payload, 0x00, 0x03, 0x00, 0x6a))
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return true;
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if (len == 94 && MATCH(payload, 0x00, 0x03, 0x00, 0x4a))
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return true;
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return false;
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}
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static inline bool match_rtp(lpi_data_t *data, lpi_module_t *mod UNUSED) {
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/* Watch out for one-way DNS... */
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if (data->client_port == 53 || data->server_port == 53) {
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if (data->payload_len[0] == 0 || data->payload_len[1] == 0)
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return false;
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}
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// Exclude QUIC port
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if (data->client_port == 443 || data->server_port == 443)
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return false;
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if (match_rtp_806d(data->payload[0], data->payload_len[0])) {
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if (match_rtp_payload(data->payload[1], data->payload_len[1],
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data->payload_len[0]))
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return true;
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}
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if (match_rtp_806d(data->payload[1], data->payload_len[1])) {
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if (match_rtp_payload(data->payload[0], data->payload_len[0],
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data->payload_len[1]))
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return true;
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}
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if (match_rtp_80c9(data->payload[0], data->payload_len[0])) {
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if (match_stun_response(data->payload[1], data->payload_len[1]))
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return true;
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}
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if (match_rtp_80c9(data->payload[1], data->payload_len[1])) {
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if (match_stun_response(data->payload[0], data->payload_len[0]))
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return true;
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}
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if (match_rtp_payload(data->payload[0], data->payload_len[0],
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data->payload_len[1])) {
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if (match_stun_response(data->payload[1], data->payload_len[1]))
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return true;
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if (match_rtp_payload(data->payload[1], data->payload_len[1],
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data->payload_len[0])) {
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uint32_t a = ntohl(data->payload[0]) & 0xffff0000;
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uint32_t b = ntohl(data->payload[1]) & 0xffff0000;
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if (a == b)
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return true;
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return false;
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}
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if (data->payload_len[1] == 0)
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return true;
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}
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if (match_rtp_payload(data->payload[1], data->payload_len[1],
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data->payload_len[0])) {
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if (match_stun_response(data->payload[0], data->payload_len[0]))
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return true;
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if (data->payload_len[0] == 0)
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return true;
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}
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if (match_rtcp_report(data->payload[0], data->payload_len[0])) {
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if (match_rtp_payload(data->payload[1], data->payload_len[1],
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data->payload_len[0]))
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return true;
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}
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if (match_rtcp_report(data->payload[1], data->payload_len[1])) {
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if (match_rtp_payload(data->payload[0], data->payload_len[0],
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data->payload_len[1]))
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return true;
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}
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return false;
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}
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static lpi_module_t lpi_rtp = {
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LPI_PROTO_UDP_RTP,
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LPI_CATEGORY_VOIP,
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"RTP",
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33,
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match_rtp
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};
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void register_rtp(LPIModuleMap *mod_map) {
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register_protocol(&lpi_rtp, mod_map);
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}
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