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
|
/* packet-x75.c
* Routines for X.75 frame disassembly
* Manawyrm <git@tbspace.de>
*
* based on lapb dissector by
* Olivier Abad <oabad@noos.fr>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/decode_as.h>
#include <epan/packet.h>
#include <wiretap/wtap.h>
#include <epan/xdlc.h>
static dissector_table_t x75_subdissector_table;
void proto_register_x75(void);
void proto_reg_handoff_x75(void);
#define X75_ADDRESS_SLP_STE_A 0x03
#define X75_ADDRESS_SLP_STE_B 0x01
#define X75_ADDRESS_MLP_STE_C 0x0F
#define X75_ADDRESS_MLP_STE_D 0x07
static int proto_x75;
static int hf_x75_address;
static int hf_x75_control;
static int hf_x75_n_r;
static int hf_x75_n_s;
static int hf_x75_p;
static int hf_x75_f;
static int hf_x75_s_ftype;
static int hf_x75_u_modifier_cmd;
static int hf_x75_u_modifier_resp;
static int hf_x75_ftype_i;
static int hf_x75_ftype_s_u;
static int ett_x75;
static int ett_x75_control;
static dissector_handle_t data_handle;
static dissector_handle_t x75_handle;
static const xdlc_cf_items x75_cf_items = {
&hf_x75_n_r,
&hf_x75_n_s,
&hf_x75_p,
&hf_x75_f,
&hf_x75_s_ftype,
&hf_x75_u_modifier_cmd,
&hf_x75_u_modifier_resp,
&hf_x75_ftype_i,
&hf_x75_ftype_s_u
};
static int
dissect_x75(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_tree *x75_tree, *ti;
uint16_t control;
int is_response;
uint8_t byte0;
tvbuff_t *next_tvb;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.75");
col_set_str(pinfo->cinfo, COL_RES_NET_DST, "Broadcast");
byte0 = tvb_get_uint8(tvb, 0);
if (byte0 != X75_ADDRESS_SLP_STE_A && byte0 != X75_ADDRESS_SLP_STE_B &&
byte0 != X75_ADDRESS_MLP_STE_C && byte0 != X75_ADDRESS_MLP_STE_D) /* invalid X.75 frame */
{
col_set_str(pinfo->cinfo, COL_INFO, "Invalid X.75 frame");
if (tree)
proto_tree_add_protocol_format(tree, proto_x75, tvb, 0, -1,
"Invalid X.75 frame");
return 1;
}
// Clear lower layer src/dst address types, so our custom names
// are shown in the Packet List pane
pinfo->src.type = AT_NONE;
pinfo->dst.type = AT_NONE;
switch (pinfo->p2p_dir) {
case P2P_DIR_SENT:
if (byte0 == X75_ADDRESS_SLP_STE_A || byte0 == X75_ADDRESS_SLP_STE_B)
{
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE A");
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE B");
}
else
{
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE C");
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE D");
}
if (byte0 == X75_ADDRESS_SLP_STE_A || byte0 == X75_ADDRESS_MLP_STE_C)
is_response = true;
else
is_response = false;
break;
case P2P_DIR_RECV:
if (byte0 == X75_ADDRESS_SLP_STE_A || byte0 == X75_ADDRESS_SLP_STE_B)
{
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE B");
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE A");
}
else
{
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "STE D");
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "STE C");
}
if (byte0 == X75_ADDRESS_SLP_STE_B || byte0 == X75_ADDRESS_MLP_STE_D)
is_response = true;
else
is_response = false;
break;
default:
is_response = false;
break;
}
if (is_response)
{
col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.75 RSP");
}
else
{
col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.75 CMD");
}
ti = proto_tree_add_protocol_format(tree, proto_x75, tvb, 0, 2,
"X.75");
x75_tree = proto_item_add_subtree(ti, ett_x75);
proto_tree_add_uint(x75_tree, hf_x75_address, tvb, 0, 1, byte0);
control = dissect_xdlc_control(tvb, 1, pinfo, x75_tree, hf_x75_control,
ett_x75_control, &x75_cf_items, NULL, NULL, NULL,
is_response, false, false);
/* information frame ==> data */
if (XDLC_IS_INFORMATION(control)) {
next_tvb = tvb_new_subset_remaining(tvb, 2);
int len = tvb_reported_length_remaining(next_tvb, 0);
// limit number of bytes being shown in COL_INFO
if (len > 128)
len = 128;
col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", tvb_format_text(pinfo->pool, next_tvb, 0, len));
if (!dissector_try_payload_new(x75_subdissector_table, next_tvb, pinfo, tree, true, NULL)) {
call_dissector(data_handle, next_tvb, pinfo, tree);
}
}
return tvb_captured_length(tvb);
}
void
proto_register_x75(void)
{
static hf_register_info hf[] = {
{ &hf_x75_address,
{ "Address", "x75.address", FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL }},
{ &hf_x75_control,
{ "Control Field", "x75.control", FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL }},
{ &hf_x75_n_r,
{ "N(R)", "x75.control.n_r", FT_UINT8, BASE_DEC,
NULL, XDLC_N_R_MASK, NULL, HFILL }},
{ &hf_x75_n_s,
{ "N(S)", "x75.control.n_s", FT_UINT8, BASE_DEC,
NULL, XDLC_N_S_MASK, NULL, HFILL }},
{ &hf_x75_p,
{ "Poll", "x75.control.p", FT_BOOLEAN, 8,
TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
{ &hf_x75_f,
{ "Final", "x75.control.f", FT_BOOLEAN, 8,
TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }},
{ &hf_x75_s_ftype,
{ "Supervisory frame type", "x75.control.s_ftype", FT_UINT8, BASE_HEX,
VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL }},
{ &hf_x75_u_modifier_cmd,
{ "Command", "x75.control.u_modifier_cmd", FT_UINT8, BASE_HEX,
VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
{ &hf_x75_u_modifier_resp,
{ "Response", "x75.control.u_modifier_resp", FT_UINT8, BASE_HEX,
VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL }},
{ &hf_x75_ftype_i,
{ "Frame type", "x75.control.ftype", FT_UINT8, BASE_HEX,
VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL }},
{ &hf_x75_ftype_s_u,
{ "Frame type", "x75.control.ftype", FT_UINT8, BASE_HEX,
VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }},
};
static int *ett[] = {
&ett_x75,
&ett_x75_control,
};
proto_x75 = proto_register_protocol("Async data over ISDN (X.75)",
"X.75", "x75");
proto_register_field_array (proto_x75, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
x75_handle = register_dissector("x75", dissect_x75, proto_x75);
x75_subdissector_table =
register_decode_as_next_proto(proto_x75,
"x75.subdissector", "X.75 payload subdissector", NULL);
}
void
proto_reg_handoff_x75(void)
{
data_handle = find_dissector("data");
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
|
