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
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
|
/*
* sip.c
*
* Copyright (C) 2009-11 - ipoque GmbH
* Copyright (C) 2011-22 - 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_protocol_ids.h"
#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_SIP
#include "ndpi_api.h"
#include "ndpi_private.h"
static void search_metadata(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow);
static void ndpi_int_sip_add_connection(struct ndpi_detection_module_struct *ndpi_struct,
struct ndpi_flow_struct *flow) {
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_SIP, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
search_metadata(ndpi_struct, flow);
}
/* ********************************************************** */
static int search_cmd(struct ndpi_detection_module_struct *ndpi_struct)
{
struct ndpi_packet_struct *packet = &ndpi_struct->packet;
const u_int8_t *packet_payload = packet->payload;
u_int32_t payload_len = packet->payload_packet_len;
const char **cs;
size_t length;
const char *cmds_a[] = { "Ack sip",
"Ack tel",
NULL };
const char *cmds_b[] = { "Bye sip",
NULL};
const char *cmds_c[] = { "Cancel sip",
"Cancel tel",
NULL};
const char *cmds_i[] = { "Invite sip",
"Info sip",
NULL};
const char *cmds_m[] = { "Message sip",
NULL};
const char *cmds_n[] = { "Notify sip",
NULL};
const char *cmds_o[] = { "Options sip",
"Options tel",
NULL};
const char *cmds_p[] = { "Publish sip",
"Prack sip",
NULL};
const char *cmds_r[] = { "Register sip",
"Refer sip",
NULL};
const char *cmds_s[] = { "Subscribe sip",
"SIP/2.0", /* Reply; useful with asymmetric flows */
NULL};
switch(packet_payload[0]) {
case 'a':
case 'A':
cs = cmds_a;
break;
case 'b':
case 'B':
cs = cmds_b;
break;
case 'c':
case 'C':
cs = cmds_c;
break;
case 'i':
case 'I':
cs = cmds_i;
break;
case 'm':
case 'M':
cs = cmds_m;
break;
case 'n':
case 'N':
cs = cmds_n;
break;
case 'o':
case 'O':
cs = cmds_o;
break;
case 'p':
case 'P':
cs = cmds_p;
break;
case 'r':
case 'R':
cs = cmds_r;
break;
case 's':
case 'S':
cs = cmds_s;
break;
default:
return 0;
}
while(*cs) {
length = strlen(*cs);
if(payload_len > length &&
strncasecmp((const char *)packet_payload, *cs, length) == 0) {
NDPI_LOG_DBG(ndpi_struct, "Matching with [%s]\n", *cs);
return 1;
}
cs++;
}
return 0;
}
/* ********************************************************** */
static char *get_imsi(const char *str, int *imsi_len)
{
char *s, *e, *c;
/* Format: <sip:XXXXXXXXXXXXXXX@ims.mncYYY.mccZZZ.3gppnetwork.org>;tag=YpUNxYCzz0dMHM */
s = ndpi_strnstr(str, "<sip:", strlen(str));
if(!s)
return NULL;
e = ndpi_strnstr(s, "@", strlen(s));
if(!e)
return NULL;
*imsi_len = e - s - 5;
/* IMSI is 14 or 15 digit length */
if(*imsi_len != 14 && *imsi_len != 15)
return NULL;
for(c = s + 5; c != e; c++)
if(!isdigit(*c))
return NULL;
return s + 5;
}
/* ********************************************************** */
static int metadata_enabled(struct ndpi_detection_module_struct *ndpi_struct)
{
/* At least one */
return ndpi_struct->cfg.sip_attribute_from_enabled ||
ndpi_struct->cfg.sip_attribute_from_imsi_enabled ||
ndpi_struct->cfg.sip_attribute_to_enabled ||
ndpi_struct->cfg.sip_attribute_to_imsi_enabled;
}
/* ********************************************************** */
static void search_metadata(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct *packet = &ndpi_struct->packet;
u_int16_t a;
int str_len, imsi_len;
char *str, *imsi;
if(!metadata_enabled(ndpi_struct))
return;
NDPI_PARSE_PACKET_LINE_INFO(ndpi_struct, flow, packet);
for(a = 0; a < packet->parsed_lines; a++) {
/* From */
if(ndpi_struct->cfg.sip_attribute_from_enabled &&
flow->protos.sip.from == NULL &&
packet->line[a].len >= 5 &&
memcmp(packet->line[a].ptr, "From:", 5) == 0) {
str_len = packet->line[a].len - 5;
str = ndpi_strip_leading_trailing_spaces((char *)packet->line[a].ptr + 5, &str_len);
if(str) {
NDPI_LOG_DBG2(ndpi_struct, "Found From: %.*s\n", str_len, str);
flow->protos.sip.from = ndpi_strndup(str, str_len);
if(ndpi_struct->cfg.sip_attribute_from_imsi_enabled &&
flow->protos.sip.from) {
imsi = get_imsi(flow->protos.sip.from, &imsi_len);
if(imsi) {
NDPI_LOG_DBG2(ndpi_struct, "Found From IMSI: %.*s\n", imsi_len, imsi);
memcpy(flow->protos.sip.from_imsi, imsi, imsi_len);
}
}
}
}
/* To */
if(ndpi_struct->cfg.sip_attribute_to_enabled &&
flow->protos.sip.to == NULL &&
packet->line[a].len >= 3 &&
memcmp(packet->line[a].ptr, "To:", 3) == 0) {
str_len = packet->line[a].len - 3;
str = ndpi_strip_leading_trailing_spaces((char *)packet->line[a].ptr + 3, &str_len);
if(str) {
NDPI_LOG_DBG2(ndpi_struct, "Found To: %.*s\n", str_len, str);
flow->protos.sip.to = ndpi_strndup(str, str_len);
if(ndpi_struct->cfg.sip_attribute_to_imsi_enabled &&
flow->protos.sip.to) {
imsi = get_imsi(flow->protos.sip.to, &imsi_len);
if(imsi) {
NDPI_LOG_DBG2(ndpi_struct, "Found To IMSI: %.*s\n", imsi_len, imsi);
memcpy(flow->protos.sip.to_imsi, imsi, imsi_len);
}
}
}
}
}
}
/* ********************************************************** */
static void ndpi_search_sip(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) {
struct ndpi_packet_struct *packet = &ndpi_struct->packet;
const u_int8_t *packet_payload = packet->payload;
u_int32_t payload_len = packet->payload_packet_len;
NDPI_LOG_DBG(ndpi_struct, "Searching for SIP\n");
if(flow->packet_counter >= 8) {
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
if(payload_len > 4) {
/* search for STUN Turn ChannelData Prefix */
u_int16_t message_len = ntohs(get_u_int16_t(packet->payload, 2));
if(payload_len - 4 == message_len) {
NDPI_LOG_DBG2(ndpi_struct, "found STUN TURN ChannelData prefix\n");
payload_len -= 4;
packet_payload += 4;
}
if(!isprint(packet_payload[0])) {
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
}
if(payload_len == 5 && memcmp(packet_payload, "hello", 5) == 0) {
NDPI_LOG_INFO(ndpi_struct, "found sip via HELLO (kind of ping)\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}
if(payload_len >= 30) { /* Arbitrary value: SIP packets are quite big */
if(search_cmd(ndpi_struct) == 1) {
NDPI_LOG_INFO(ndpi_struct, "found sip command\n");
ndpi_int_sip_add_connection(ndpi_struct, flow);
return;
}
}
}
/* ********************************************************** */
void init_sip_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id) {
ndpi_set_bitmask_protocol_detection("SIP", ndpi_struct, *id,
NDPI_PROTOCOL_SIP,
ndpi_search_sip,
NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,/* Fix courtesy of Miguel Quesada <mquesadab@gmail.com> */
SAVE_DETECTION_BITMASK_AS_UNKNOWN,
ADD_TO_DETECTION_BITMASK);
*id += 1;
}
|