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wireshark/epan/dissectors/packet-whois.c

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/* packet-whois.c
* Routines for whois dissection (see https://tools.ietf.org/html/rfc3912)
* 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"
#define WHOIS_PORT 43 /* This is the registered IANA port (nicname) */
void proto_register_whois(void);
void proto_reg_handoff_whois(void);
static int proto_whois = -1;
static int hf_whois_query = -1;
static int hf_whois_answer = -1;
static int hf_whois_answer_in = -1;
static int hf_whois_answer_to = -1;
static int hf_whois_response_time = -1;
static expert_field ei_whois_nocrlf = EI_INIT;
static expert_field ei_whois_encoding = EI_INIT;
static gint ett_whois = -1;
typedef struct _whois_transaction_t {
guint32 req_frame;
guint32 rep_frame;
nstime_t req_time;
guint8* query;
} whois_transaction_t;
static int
dissect_whois(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
void *data)
{
proto_item *ti, *expert_ti;
proto_tree *whois_tree;
conversation_t *conversation;
whois_transaction_t *whois_trans;
gboolean is_query;
guint len;
struct tcpinfo *tcpinfo = (struct tcpinfo*)data;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "WHOIS");
if (pinfo->destport == WHOIS_PORT) {
is_query = TRUE;
col_set_str(pinfo->cinfo, COL_INFO, "Query");
} else {
is_query = FALSE;
col_set_str(pinfo->cinfo, COL_INFO, "Answer");
}
conversation = find_or_create_conversation(pinfo);
whois_trans = (whois_transaction_t *)conversation_get_proto_data(conversation, proto_whois);
if (whois_trans == NULL) {
gint linelen;
whois_trans = wmem_new0(wmem_file_scope(), whois_transaction_t);
/*
* Find the end of the first line.
*/
linelen = tvb_find_line_end(tvb, 0, -1, NULL, FALSE);
if (linelen != -1)
whois_trans->query = tvb_get_string_enc(wmem_file_scope(), tvb, 0, linelen, ENC_ASCII|ENC_NA);
conversation_add_proto_data(conversation, proto_whois, whois_trans);
}
if (whois_trans->query) {
col_append_str(pinfo->cinfo, COL_INFO, ": ");
col_append_str(pinfo->cinfo, COL_INFO, whois_trans->query);
}
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 guint8*)"\r\n", 2))) {
pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
pinfo->desegment_offset = 0;
return -1;
} else {
whois_trans->req_frame = pinfo->num;
whois_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 && (whois_trans->req_frame == 0)) {
whois_trans->req_frame = pinfo->num;
whois_trans->req_time = pinfo->abs_ts;
}
if (!is_query && (whois_trans->rep_frame == 0)) {
/* By comparing whois_trans->rep_frame to 0, if reassembly is turned
* on, whois_trans->rep_frame will be assigned to the reassembled frame
* number, and if reassembly is turned off, whois_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 > whois_trans->rep_frame)
* which will give us the same frame number either way.
*/
whois_trans->rep_frame = pinfo->num;
}
ti = proto_tree_add_protocol_format(tree, proto_whois, tvb, 0, -1,
"WHOIS: %s", is_query ? "Query" : "Answer");
whois_tree = proto_item_add_subtree(ti, ett_whois);
/*
* XXX - WHOIS, as RFC 3912 says, "has no mechanism for indicating
* the character set in use." We assume UTF-8, which is backwards
* compatible with ASCII; if somebody wants to support WHOIS requests
* or responses in other encodings, they should add a preference.
* (Show Packet Bytes works well enough for many use cases.)
* Some servers do use other character encodings;
* e.g., in 2022 RIPE still uses ISO-8859-1.
*/
if (is_query) {
expert_ti = proto_tree_add_item(whois_tree, hf_whois_query, tvb, 0, -1, ENC_ASCII);
if ((len < 2) || (tvb_memeql(tvb, len - 2, (const guint8*)"\r\n", 2))) {
/*
* From RFC3912, section 2:
* All requests are terminated with ASCII CR and then ASCII LF.
*/
expert_add_info(pinfo, expert_ti, &ei_whois_nocrlf);
}
if (tree && whois_trans->rep_frame) {
ti = proto_tree_add_uint(whois_tree, hf_whois_answer_in,
tvb, 0, 0, whois_trans->rep_frame);
proto_item_set_generated(ti);
}
} else if (tree && whois_trans->rep_frame) {
/*
* If we know the request frame, show it and the time delta between
* the request and the response.
*/
if (whois_trans->req_frame) {
nstime_t ns;
ti = proto_tree_add_uint(whois_tree, hf_whois_answer_to,
tvb, 0, 0, whois_trans->req_frame);
proto_item_set_generated(ti);
if (pinfo->num == whois_trans->rep_frame) {
nstime_delta(&ns, &pinfo->abs_ts, &whois_trans->req_time);
ti = proto_tree_add_time(whois_tree, hf_whois_response_time, tvb, 0, 0, &ns);
proto_item_set_generated(ti);
}
}
/*
* Show the response as text, a line at a time.
*/
int offset = 0, next_offset;
while (tvb_offset_exists(tvb, offset)) {
/*
* Find the end of the line.
*/
tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
/*
* Put this line.
*/
proto_tree_add_item(whois_tree, hf_whois_answer, tvb, offset,
next_offset - offset, ENC_UTF_8);
offset = next_offset;
}
proto_tree_add_expert(whois_tree, pinfo, &ei_whois_encoding, tvb, 0, -1);
}
return tvb_captured_length(tvb);
}
void
proto_register_whois(void)
{
expert_module_t *expert_whois;
static hf_register_info hf[] = {
{ &hf_whois_query,
{ "Query", "whois.query", FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_whois_answer,
{ "Answer", "whois.answer", FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
{ &hf_whois_answer_in,
{ "Answer In", "whois.answer_in", FT_FRAMENUM, BASE_NONE, NULL,
0x0, "The answer to this WHOIS query is in this frame",
HFILL }
},
{ &hf_whois_answer_to,
{ "Query In", "whois.answer_to", FT_FRAMENUM, BASE_NONE, NULL,
0x0, "This is the answer to the WHOIS query in this frame",
HFILL }
},
{ &hf_whois_response_time,
{ "Response Time", "whois.response_time", FT_RELATIVE_TIME,
BASE_NONE, NULL, 0x0,
"The time between the Query and the Answer", HFILL }
}
};
static gint *ett[] = {
&ett_whois
};
static ei_register_info ei[] = {
{ &ei_whois_nocrlf,
{ "whois.nocrlf", PI_MALFORMED, PI_WARN, "Missing <CR><LF>", EXPFILL}
},
{ &ei_whois_encoding,
{ "whois.encoding", PI_ASSUMPTION, PI_CHAT, "WHOIS has no mechanism to indicate encoding (RFC 3912), assuming UTF-8", EXPFILL}
}
};
proto_whois = proto_register_protocol("whois", "WHOIS", "whois");
proto_register_field_array(proto_whois, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_whois = expert_register_protocol(proto_whois);
expert_register_field_array(expert_whois, ei, array_length(ei));
}
void
proto_reg_handoff_whois(void)
{
static dissector_handle_t whois_handle;
whois_handle = create_dissector_handle(dissect_whois, proto_whois);
dissector_add_uint_with_preference("tcp.port", WHOIS_PORT, whois_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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