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/* packet-finger.c
* Routines for basic finger dissection (see https://tools.ietf.org/html/rfc742)
* Copyright 2013, Christopher Maynard <Christopher.Maynard@gtech.com>
*
* 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>
#include <epan/conversation.h>
#include <epan/expert.h>
#include "packet-tcp.h"
void proto_register_finger(void);
void proto_reg_handoff_finger(void);
static dissector_handle_t finger_handle;
#define FINGER_PORT 79 /* This is the registered IANA port */
static int proto_finger;
static int hf_finger_query;
static int hf_finger_response;
static int hf_finger_response_in;
static int hf_finger_response_to;
static int hf_finger_response_time;
static expert_field ei_finger_nocrlf;
static int ett_finger;
typedef struct _finger_transaction_t {
uint32_t req_frame;
uint32_t rep_frame;
nstime_t req_time;
} finger_transaction_t;
static int
dissect_finger(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
void *data)
{
proto_item *ti, *expert_ti;
proto_tree *finger_tree;
conversation_t *conversation;
finger_transaction_t *finger_trans;
bool is_query;
unsigned len;
struct tcpinfo *tcpinfo = (struct tcpinfo*)data;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "FINGER");
if (pinfo->destport == FINGER_PORT) {
is_query = true;
col_set_str(pinfo->cinfo, COL_INFO, "Query");
} else {
is_query = false;
col_set_str(pinfo->cinfo, COL_INFO, "Response");
}
conversation = find_or_create_conversation(pinfo);
finger_trans = (finger_transaction_t *)conversation_get_proto_data(conversation, proto_finger);
if (finger_trans == NULL) {
finger_trans = wmem_new0(wmem_file_scope(), finger_transaction_t);
conversation_add_proto_data(conversation, proto_finger, finger_trans);
}
len = tvb_reported_length(tvb);
if (!PINFO_FD_VISITED(pinfo)) {
if (pinfo->can_desegment) {
if (is_query) {
if ((len < 2) || (tvb_memeql(tvb, len - 2, (const uint8_t*)"\r\n", 2))) {
pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
pinfo->desegment_offset = 0;
return -1;
} else {
finger_trans->req_frame = pinfo->num;
finger_trans->req_time = pinfo->abs_ts;
}
} else if (!(tcpinfo && (IS_TH_FIN(tcpinfo->flags) || tcpinfo->is_reassembled))) {
/* If this is the FIN (or already desegmented, as with an out
* of order segment received after FIN) go ahead and dissect
* on the first pass.
*/
pinfo->desegment_len = DESEGMENT_UNTIL_FIN;
pinfo->desegment_offset = 0;
return -1;
}
}
} else if (is_query && (finger_trans->req_frame == 0)) {
finger_trans->req_frame = pinfo->num;
finger_trans->req_time = pinfo->abs_ts;
}
if (!is_query && (finger_trans->rep_frame == 0)) {
/* By comparing finger_trans->rep_frame to 0, if reassembly is turned
* on, finger_trans->rep_frame will be assigned to the reassembled frame
* number, and if reassembly is turned off, finger_trans->rep_frame will
* be assigned to the first frame number of the response. This seems
* to match other protocols' behavior. The alternative is:
* if (pinfo->num > finger_trans->rep_frame)
* which will give us the same frame number either way.
*/
finger_trans->rep_frame = pinfo->num;
}
ti = proto_tree_add_protocol_format(tree, proto_finger, tvb, 0, -1,
"FINGER: %s", is_query ? "Query" : "Response");
finger_tree = proto_item_add_subtree(ti, ett_finger);
if (is_query) {
expert_ti = proto_tree_add_item(finger_tree, hf_finger_query, tvb, 0, -1, ENC_ASCII);
if ((len < 2) || (tvb_memeql(tvb, len - 2, (const uint8_t*)"\r\n", 2))) {
/*
* From RFC742, Send a single "command line", ending with <CRLF>.
*/
expert_add_info(pinfo, expert_ti, &ei_finger_nocrlf);
}
if (tree && finger_trans->rep_frame) {
ti = proto_tree_add_uint(finger_tree, hf_finger_response_in,
tvb, 0, 0, finger_trans->rep_frame);
proto_item_set_generated(ti);
}
} else if (tree && finger_trans->rep_frame) {
proto_tree_add_item(finger_tree, hf_finger_response, tvb, 0, -1, ENC_ASCII);
if (finger_trans->req_frame) {
nstime_t ns;
ti = proto_tree_add_uint(finger_tree, hf_finger_response_to,
tvb, 0, 0, finger_trans->req_frame);
proto_item_set_generated(ti);
if (pinfo->num == finger_trans->rep_frame) {
nstime_delta(&ns, &pinfo->abs_ts, &finger_trans->req_time);
ti = proto_tree_add_time(finger_tree, hf_finger_response_time, tvb, 0, 0, &ns);
proto_item_set_generated(ti);
}
}
}
return tvb_captured_length(tvb);
}
void
proto_register_finger(void)
{
expert_module_t *expert_finger;
static hf_register_info hf[] = {
{ &hf_finger_query,
{ "Query", "finger.query", FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_finger_response,
{ "Response", "finger.response", FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_finger_response_in,
{ "Response In", "finger.response_in", FT_FRAMENUM, BASE_NONE, NULL,
0x0, "The response to this FINGER query is in this frame",
HFILL }
},
{ &hf_finger_response_to,
{ "Request In", "finger.response_to", FT_FRAMENUM, BASE_NONE, NULL,
0x0, "This is a response to the FINGER query in this frame",
HFILL }
},
{ &hf_finger_response_time,
{ "Response Time", "finger.response_time", FT_RELATIVE_TIME,
BASE_NONE, NULL, 0x0,
"The time between the Query and the Response", HFILL }
}
};
static int *ett[] = {
&ett_finger
};
static ei_register_info ei[] = {
{ &ei_finger_nocrlf,
{ "finger.nocrlf", PI_MALFORMED, PI_WARN, "Missing <CR><LF>", EXPFILL}
}
};
proto_finger = proto_register_protocol("finger", "FINGER", "finger");
finger_handle = register_dissector("finger", dissect_finger, proto_finger);
proto_register_field_array(proto_finger, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_finger = expert_register_protocol(proto_finger);
expert_register_field_array(expert_finger, ei, array_length(ei));
}
void
proto_reg_handoff_finger(void)
{
dissector_add_uint_with_preference("tcp.port", FINGER_PORT, finger_handle);
}
/*
* 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:
*/
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