/src/ndpi/src/lib/protocols/dnscrypt.c
Line | Count | Source (jump to first uncovered line) |
1 | | /* |
2 | | * dnscrypt.c |
3 | | * |
4 | | * Copyright (C) 2020 - ntop.org |
5 | | * |
6 | | * nDPI is free software: you can redistribute it and/or modify |
7 | | * it under the terms of the GNU Lesser General Public License as published by |
8 | | * the Free Software Foundation, either version 3 of the License, or |
9 | | * (at your option) any later version. |
10 | | * |
11 | | * nDPI is distributed in the hope that it will be useful, |
12 | | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | | * GNU Lesser General Public License for more details. |
15 | | * |
16 | | * You should have received a copy of the GNU Lesser General Public License |
17 | | * along with nDPI. If not, see <http://www.gnu.org/licenses/>. |
18 | | * |
19 | | */ |
20 | | |
21 | | #include "ndpi_protocol_ids.h" |
22 | | |
23 | | #define NDPI_CURRENT_PROTO NDPI_PROTOCOL_DNSCRYPT |
24 | | |
25 | | #include "ndpi_api.h" |
26 | | #include "ndpi_private.h" |
27 | | |
28 | | static void ndpi_int_dnscrypt_add_connection(struct ndpi_detection_module_struct *ndpi_struct, |
29 | | struct ndpi_flow_struct *flow) |
30 | 0 | { |
31 | 0 | ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_DNSCRYPT, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI); |
32 | 0 | } |
33 | | |
34 | | static void ndpi_search_dnscrypt(struct ndpi_detection_module_struct *ndpi_struct, |
35 | | struct ndpi_flow_struct *flow) |
36 | 0 | { |
37 | 0 | struct ndpi_packet_struct *packet = &ndpi_struct->packet; |
38 | 0 | static char const * const dnscrypt_initial = "2\rdnscrypt"; |
39 | |
|
40 | 0 | NDPI_LOG_DBG(ndpi_struct, "search dnscrypt\n"); |
41 | | |
42 | | /* dnscrypt protocol version 1: check magic */ |
43 | 0 | if (packet->payload_packet_len >= 64 && |
44 | 0 | strncmp((char*)packet->payload, "r6fnvWj8", strlen("r6fnvWj8")) == 0) |
45 | 0 | { |
46 | 0 | ndpi_int_dnscrypt_add_connection(ndpi_struct, flow); |
47 | 0 | return; |
48 | 0 | } |
49 | | |
50 | | /* dnscrypt protocol version 1 and 2: resolver ping */ |
51 | 0 | if (packet->payload_packet_len > 13 + strlen(dnscrypt_initial) && |
52 | 0 | strncasecmp((char*)packet->payload + 13, dnscrypt_initial, strlen(dnscrypt_initial)) == 0) |
53 | 0 | { |
54 | 0 | ndpi_int_dnscrypt_add_connection(ndpi_struct, flow); |
55 | 0 | return; |
56 | 0 | } |
57 | | |
58 | 0 | if ((flow->packet_direction_counter[packet->packet_direction] >= 1 && |
59 | 0 | flow->packet_direction_counter[1 - packet->packet_direction] >= 1) || |
60 | 0 | flow->packet_counter >= 8) { |
61 | | /* |
62 | | * Wait for at least one packet per direction, up to a max |
63 | | * Required as we need to wait for the server response which contains the ASCII pattern below. |
64 | | */ |
65 | 0 | NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow); |
66 | 0 | return; |
67 | 0 | } |
68 | 0 | } |
69 | | |
70 | | void init_dnscrypt_dissector(struct ndpi_detection_module_struct *ndpi_struct) |
71 | 1 | { |
72 | 1 | register_dissector("DNScrypt", ndpi_struct, |
73 | 1 | ndpi_search_dnscrypt, |
74 | 1 | NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION, |
75 | 1 | 1, NDPI_PROTOCOL_DNSCRYPT); |
76 | 1 | } |
77 | | |