1 /* packet-finger.c
2 * Routines for basic finger dissection (see https://tools.ietf.org/html/rfc742)
3 * Copyright 2013, Christopher Maynard <Christopher.Maynard@gtech.com>
4 *
5 * Wireshark - Network traffic analyzer
6 * By Gerald Combs <gerald@wireshark.org>
7 * Copyright 1998 Gerald Combs
8 *
9 * SPDX-License-Identifier: GPL-2.0-or-later
10 */
11
12 #include "config.h"
13 #include <epan/packet.h>
14 #include <epan/conversation.h>
15 #include <epan/expert.h>
16
17 void proto_register_finger(void);
18 void proto_reg_handoff_finger(void);
19
20 #define FINGER_PORT 79 /* This is the registered IANA port */
21
22 static int proto_finger = -1;
23 static int hf_finger_query = -1;
24 static int hf_finger_response = -1;
25 static int hf_finger_response_in = -1;
26 static int hf_finger_response_to = -1;
27 static int hf_finger_response_time = -1;
28
29 static expert_field ei_finger_nocrlf = EI_INIT;
30
31 static gint ett_finger = -1;
32
33 typedef struct _finger_transaction_t {
34 guint32 req_frame;
35 guint32 rep_frame;
36 nstime_t req_time;
37 } finger_transaction_t;
38
39 static int
dissect_finger(tvbuff_t * tvb,packet_info * pinfo,proto_tree * tree,void * data _U_)40 dissect_finger(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
41 void *data _U_)
42 {
43 proto_item *ti, *expert_ti;
44 proto_tree *finger_tree;
45 conversation_t *conversation;
46 finger_transaction_t *finger_trans;
47 gboolean is_query;
48 guint len;
49
50 col_set_str(pinfo->cinfo, COL_PROTOCOL, "FINGER");
51
52 if (pinfo->destport == FINGER_PORT) {
53 is_query = TRUE;
54 col_set_str(pinfo->cinfo, COL_INFO, "Query");
55 } else {
56 is_query = FALSE;
57 col_set_str(pinfo->cinfo, COL_INFO, "Response");
58 }
59
60 conversation = find_or_create_conversation(pinfo);
61 finger_trans = (finger_transaction_t *)conversation_get_proto_data(conversation, proto_finger);
62 if (finger_trans == NULL) {
63 finger_trans = wmem_new0(wmem_file_scope(), finger_transaction_t);
64 conversation_add_proto_data(conversation, proto_finger, finger_trans);
65 }
66
67 len = tvb_reported_length(tvb);
68 if (!PINFO_FD_VISITED(pinfo)) {
69 if (pinfo->can_desegment) {
70 if (is_query) {
71 if ((len < 2) || (tvb_memeql(tvb, len - 2, "\r\n", 2))) {
72 pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
73 pinfo->desegment_offset = 0;
74 return -1;
75 } else {
76 finger_trans->req_frame = pinfo->num;
77 finger_trans->req_time = pinfo->abs_ts;
78 }
79 } else {
80 pinfo->desegment_len = DESEGMENT_UNTIL_FIN;
81 pinfo->desegment_offset = 0;
82 return -1;
83 }
84 }
85 } else if (is_query && (finger_trans->req_frame == 0)) {
86 finger_trans->req_frame = pinfo->num;
87 finger_trans->req_time = pinfo->abs_ts;
88 }
89
90 if (!is_query && (finger_trans->rep_frame == 0)) {
91 /* By comparing finger_trans->rep_frame to 0, if reassembly is turned
92 * on, finger_trans->rep_frame will be assigned to the reassembled frame
93 * number, and if reassembly is turned off, finger_trans->rep_frame will
94 * be assigned to the first frame number of the response. This seems
95 * to match other protocols' behavior. The alternative is:
96 * if (pinfo->num > finger_trans->rep_frame)
97 * which will give us the same frame number either way.
98 */
99 finger_trans->rep_frame = pinfo->num;
100 }
101
102 ti = proto_tree_add_protocol_format(tree, proto_finger, tvb, 0, -1,
103 "FINGER: %s", is_query ? "Query" : "Response");
104 finger_tree = proto_item_add_subtree(ti, ett_finger);
105
106 if (is_query) {
107 expert_ti = proto_tree_add_item(finger_tree, hf_finger_query, tvb, 0, -1, ENC_ASCII|ENC_NA);
108 if ((len < 2) || (tvb_memeql(tvb, len - 2, "\r\n", 2))) {
109 /*
110 * From RFC742, Send a single "command line", ending with <CRLF>.
111 */
112 expert_add_info(pinfo, expert_ti, &ei_finger_nocrlf);
113 }
114 if (tree && finger_trans->rep_frame) {
115 ti = proto_tree_add_uint(finger_tree, hf_finger_response_in,
116 tvb, 0, 0, finger_trans->rep_frame);
117 proto_item_set_generated(ti);
118 }
119 } else if (tree && finger_trans->rep_frame) {
120 proto_tree_add_item(finger_tree, hf_finger_response, tvb, 0, -1, ENC_ASCII|ENC_NA);
121 if (finger_trans->req_frame) {
122 nstime_t ns;
123
124 ti = proto_tree_add_uint(finger_tree, hf_finger_response_to,
125 tvb, 0, 0, finger_trans->req_frame);
126 proto_item_set_generated(ti);
127
128 if (pinfo->num == finger_trans->rep_frame) {
129 nstime_delta(&ns, &pinfo->abs_ts, &finger_trans->req_time);
130 ti = proto_tree_add_time(finger_tree, hf_finger_response_time, tvb, 0, 0, &ns);
131 proto_item_set_generated(ti);
132 }
133 }
134 }
135
136 return tvb_captured_length(tvb);
137 }
138
139 void
proto_register_finger(void)140 proto_register_finger(void)
141 {
142 expert_module_t *expert_finger;
143
144 static hf_register_info hf[] = {
145 { &hf_finger_query,
146 { "Query", "finger.query", FT_STRING, BASE_NONE, NULL, 0x0,
147 NULL, HFILL }
148 },
149 { &hf_finger_response,
150 { "Response", "finger.response", FT_STRING, BASE_NONE, NULL, 0x0,
151 NULL, HFILL }
152 },
153 { &hf_finger_response_in,
154 { "Response In", "finger.response_in", FT_FRAMENUM, BASE_NONE, NULL,
155 0x0, "The response to this FINGER query is in this frame",
156 HFILL }
157 },
158 { &hf_finger_response_to,
159 { "Request In", "finger.response_to", FT_FRAMENUM, BASE_NONE, NULL,
160 0x0, "This is a response to the FINGER query in this frame",
161 HFILL }
162 },
163 { &hf_finger_response_time,
164 { "Response Time", "finger.response_time", FT_RELATIVE_TIME,
165 BASE_NONE, NULL, 0x0,
166 "The time between the Query and the Response", HFILL }
167 }
168 };
169
170 static gint *ett[] = {
171 &ett_finger
172 };
173
174 static ei_register_info ei[] = {
175 { &ei_finger_nocrlf,
176 { "finger.nocrlf", PI_MALFORMED, PI_WARN, "Missing <CR><LF>", EXPFILL}
177 }
178 };
179
180 proto_finger = proto_register_protocol("finger", "FINGER", "finger");
181 proto_register_field_array(proto_finger, hf, array_length(hf));
182 proto_register_subtree_array(ett, array_length(ett));
183 expert_finger = expert_register_protocol(proto_finger);
184 expert_register_field_array(expert_finger, ei, array_length(ei));
185 }
186
187 void
proto_reg_handoff_finger(void)188 proto_reg_handoff_finger(void)
189 {
190 static dissector_handle_t finger_handle;
191
192 finger_handle = create_dissector_handle(dissect_finger, proto_finger);
193 dissector_add_uint_with_preference("tcp.port", FINGER_PORT, finger_handle);
194 }
195
196 /*
197 * Editor modelines - https://www.wireshark.org/tools/modelines.html
198 *
199 * Local variables:
200 * c-basic-offset: 4
201 * tab-width: 8
202 * indent-tabs-mode: nil
203 * End:
204 *
205 * vi: set shiftwidth=4 tabstop=8 expandtab:
206 * :indentSize=4:tabSize=8:noTabs=true:
207 */
208
209