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
|
/* packet-lpd.c
* Routines for LPR and LPRng packet disassembly
* Gilbert Ramirez <gram@alumni.rice.edu>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
void proto_register_lpd(void);
void proto_reg_handoff_lpd(void);
static dissector_handle_t lpd_handle;
#define TCP_PORT_PRINTER 515
static int proto_lpd;
static int hf_lpd_response;
static int hf_lpd_request;
static int hf_lpd_client_code;
static int hf_lpd_printer_option;
static int hf_lpd_response_code;
static int ett_lpd;
enum lpr_type { request, response, unknown };
static int find_printer_string(tvbuff_t *tvb, int offset);
/* This information comes from the LPRng HOWTO, which also describes
RFC 1179. http://www.astart.com/lprng/LPRng-HOWTO.html */
static const value_string lpd_client_code[] = {
{ 1, "LPC: start print / jobcmd: abort" },
{ 2, "LPR: transfer a printer job / jobcmd: receive control file" },
{ 3, "LPQ: print short form of queue status / jobcmd: receive data file" },
{ 4, "LPQ: print long form of queue status" },
{ 5, "LPRM: remove jobs" },
{ 6, "LPRng lpc: do control operation" },
{ 7, "LPRng lpr: transfer a block format print job" },
{ 8, "LPRng lpc: secure command transfer" },
{ 9, "LPRng lpq: verbose status information" },
{ 0, NULL }
};
static const value_string lpd_server_code[] = {
{ 0, "Success: accepted, proceed" },
{ 1, "Queue not accepting jobs" },
{ 2, "Queue temporarily full, retry later" },
{ 3, "Bad job format, do not retry" },
{ 0, NULL }
};
static int
dissect_lpd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_tree *lpd_tree;
proto_item *ti, *hidden_item;
enum lpr_type lpr_packet_type;
uint8_t code;
int printer_len;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "LPD");
col_clear(pinfo->cinfo, COL_INFO);
/* rfc1179 states that all responses are 1 byte long */
code = tvb_get_uint8(tvb, 0);
if (tvb_reported_length(tvb) == 1) {
lpr_packet_type = response;
}
else if (code <= 9) {
lpr_packet_type = request;
}
else {
lpr_packet_type = unknown;
}
if (lpr_packet_type == request && code !=0) {
col_add_str(pinfo->cinfo, COL_INFO, val_to_str(code, lpd_client_code, "Unknown client code: %u"));
}
else if (lpr_packet_type == response) {
col_set_str(pinfo->cinfo, COL_INFO, "LPD response");
}
else {
col_set_str(pinfo->cinfo, COL_INFO, "LPD continuation");
}
ti = proto_tree_add_item(tree, proto_lpd, tvb, 0, -1, ENC_NA);
lpd_tree = proto_item_add_subtree(ti, ett_lpd);
if (lpr_packet_type == response) {
hidden_item = proto_tree_add_boolean(lpd_tree, hf_lpd_response,
tvb, 0, 0, true);
} else {
hidden_item = proto_tree_add_boolean(lpd_tree, hf_lpd_request,
tvb, 0, 0, true);
}
proto_item_set_hidden(hidden_item);
if (lpr_packet_type == request) {
printer_len = find_printer_string(tvb, 1);
if (code <= 9 && printer_len != -1) {
proto_tree_add_uint_format(lpd_tree, hf_lpd_client_code, tvb, 0, 1, code,
"%s", val_to_str(code, lpd_client_code, "Unknown client code: %u"));
proto_tree_add_item(lpd_tree, hf_lpd_printer_option, tvb, 1, printer_len, ENC_ASCII);
}
else {
call_data_dissector(tvb, pinfo, lpd_tree);
}
}
else if (lpr_packet_type == response) {
if (code <= 3) {
proto_tree_add_item(lpd_tree, hf_lpd_response_code, tvb, 0, 1, ENC_BIG_ENDIAN);
}
else {
call_data_dissector(tvb, pinfo, lpd_tree);
}
}
else {
call_data_dissector(tvb, pinfo, lpd_tree);
}
return tvb_captured_length(tvb);
}
static int
find_printer_string(tvbuff_t *tvb, int offset)
{
int i;
/* try to find end of string, either '\n' or '\0' */
i = tvb_find_uint8(tvb, offset, -1, '\0');
if (i == -1)
i = tvb_find_uint8(tvb, offset, -1, '\n');
if (i == -1)
return -1;
return i - offset; /* length of string */
}
void
proto_register_lpd(void)
{
static hf_register_info hf[] = {
{ &hf_lpd_response,
{ "Response", "lpd.response",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"true if LPD response", HFILL }},
{ &hf_lpd_request,
{ "Request", "lpd.request",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"true if LPD request", HFILL }},
{ &hf_lpd_client_code,
{ "Client code", "lpd.client_code",
FT_UINT8, BASE_DEC, VALS(lpd_client_code), 0x0,
NULL, HFILL }},
{ &hf_lpd_printer_option,
{ "Printer/options", "lpd.printer_option",
FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL }},
{ &hf_lpd_response_code,
{ "Response", "lpd.response_code",
FT_UINT8, BASE_DEC, VALS(lpd_server_code), 0x0,
NULL, HFILL }},
};
static int *ett[] = {
&ett_lpd,
};
proto_lpd = proto_register_protocol("Line Printer Daemon Protocol", "LPD", "lpd");
lpd_handle = register_dissector("lpd", dissect_lpd, proto_lpd);
proto_register_field_array(proto_lpd, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_lpd(void)
{
dissector_add_uint_with_preference("tcp.port", TCP_PORT_PRINTER, lpd_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
|
