1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
/*
* snmp.c
*
* Copyright (C) 2009-2011 by ipoque GmbH
* Copyright (C) 2011-15 - ntop.org
*
* 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_protocols.h"
#ifdef NDPI_PROTOCOL_SNMP
static void ndpi_int_snmp_add_connection(struct ndpi_detection_module_struct
*ndpi_struct, struct ndpi_flow_struct *flow)
{
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_SNMP, NDPI_PROTOCOL_UNKNOWN);
}
void ndpi_search_snmp(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct *packet = &flow->packet;
// struct ndpi_id_struct *src=ndpi_struct->src;
// struct ndpi_id_struct *dst=ndpi_struct->dst;
if (packet->payload_packet_len > 32 && packet->payload[0] == 0x30) {
int offset;
switch (packet->payload[1]) {
case 0x81:
offset = 3;
break;
case 0x82:
offset = 4;
break;
default:
if (packet->payload[1] > 0x82) {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG, "SNMP excluded, second byte is > 0x82\n");
goto excl;
}
offset = 2;
}
if (get_u_int16_t(packet->payload, offset) != htons(0x0201)) {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG, "SNMP excluded, 0x0201 pattern not found\n");
goto excl;
}
if (packet->payload[offset + 2] >= 0x04) {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG, "SNMP excluded, version > 3\n");
goto excl;
}
if (flow->l4.udp.snmp_stage == 0) {
if (packet->udp->dest == htons(161) || packet->udp->dest == htons(162)) {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG, "SNMP detected due to port.\n");
ndpi_int_snmp_add_connection(ndpi_struct, flow);
return;
}
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG, "SNMP stage 0.\n");
if (packet->payload[offset + 2] == 3) {
flow->l4.udp.snmp_msg_id = ntohs(get_u_int32_t(packet->payload, offset + 8));
} else if (packet->payload[offset + 2] == 0) {
flow->l4.udp.snmp_msg_id = get_u_int8_t(packet->payload, offset + 15);
} else {
flow->l4.udp.snmp_msg_id = ntohs(get_u_int16_t(packet->payload, offset + 15));
}
flow->l4.udp.snmp_stage = 1 + packet->packet_direction;
return;
} else if (flow->l4.udp.snmp_stage == 1 + packet->packet_direction) {
if (packet->payload[offset + 2] == 0) {
if (flow->l4.udp.snmp_msg_id != get_u_int8_t(packet->payload, offset + 15) - 1) {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG,
"SNMP v1 excluded, message ID doesn't match\n");
goto excl;
}
}
} else if (flow->l4.udp.snmp_stage == 2 - packet->packet_direction) {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG, "SNMP stage 1-2.\n");
if (packet->payload[offset + 2] == 3) {
if (flow->l4.udp.snmp_msg_id != ntohs(get_u_int32_t(packet->payload, offset + 8))) {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG,
"SNMP v3 excluded, message ID doesn't match\n");
goto excl;
}
} else if (packet->payload[offset + 2] == 0) {
if (flow->l4.udp.snmp_msg_id != get_u_int8_t(packet->payload, offset + 15)) {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG,
"SNMP v1 excluded, message ID doesn't match\n");
goto excl;
}
} else {
if (flow->l4.udp.snmp_msg_id != ntohs(get_u_int16_t(packet->payload, offset + 15))) {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG,
"SNMP v2 excluded, message ID doesn't match\n");
goto excl;
}
}
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG, "SNMP detected.\n");
ndpi_int_snmp_add_connection(ndpi_struct, flow);
return;
}
} else {
NDPI_LOG(NDPI_PROTOCOL_SNMP, ndpi_struct, NDPI_LOG_DEBUG, "SNMP excluded.\n");
}
excl:
NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_SNMP);
}
#endif
|