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wireshark/epan/dissectors/packet-moldudp64.c

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/* packet-moldudp64.c
* Routines for MoldUDP64 dissection
* Copyright 2012, Evan Huus <eapache@gmail.com>
*
* http://www.nasdaqtrader.com/content/technicalsupport/specifications/dataproducts/moldudp64.pdf
*
* 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/expert.h>
#include <epan/decode_as.h>
void proto_register_moldudp64(void);
void proto_reg_handoff_moldudp64(void);
/* Initialize the protocol and registered fields */
static int proto_moldudp64 = -1;
static int hf_moldudp64_session = -1;
static int hf_moldudp64_sequence = -1;
static int hf_moldudp64_count = -1;
static int hf_moldudp64_msgblk = -1;
static int hf_moldudp64_msglen = -1;
static int hf_moldudp64_msgseq = -1;
static int hf_moldudp64_msgdata = -1;
#define MOLDUDP64_SESSION_LEN 10
#define MOLDUDP64_SEQUENCE_LEN 8
#define MOLDUDP64_COUNT_LEN 2
#define MOLDUDP64_MSGLEN_LEN 2
#define MOLDUDP64_HEARTBEAT 0x0000
#define MOLDUDP64_ENDOFSESS 0xFFFF
/* Initialize the subtree pointers */
static gint ett_moldudp64 = -1;
static gint ett_moldudp64_msgblk = -1;
static expert_field ei_moldudp64_msglen_invalid = EI_INIT;
static expert_field ei_moldudp64_end_of_session_extra = EI_INIT;
static expert_field ei_moldudp64_count_invalid = EI_INIT;
static expert_field ei_moldudp64_request = EI_INIT;
static dissector_table_t moldudp64_payload_table;
static void moldudp64_prompt(packet_info *pinfo _U_, gchar* result)
{
snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "Payload as");
}
/* Code to dissect a message block */
static guint
dissect_moldudp64_msgblk(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
guint offset, guint64 sequence)
{
proto_item *ti;
proto_tree *blk_tree;
guint16 msglen, real_msglen, whole_len;
gint remaining;
tvbuff_t* next_tvb;
if (tvb_captured_length_remaining(tvb, offset) < MOLDUDP64_MSGLEN_LEN)
return 0;
msglen = tvb_get_ntohs(tvb, offset);
remaining = tvb_reported_length(tvb) - offset - MOLDUDP64_MSGLEN_LEN;
if (remaining < 0)
real_msglen = 0;
else if (msglen <= remaining)
real_msglen = msglen;
else
real_msglen = remaining;
/* msglen and real_msglen only count the data section, and don't
* include the two bytes for the length field itself. */
whole_len = real_msglen + MOLDUDP64_MSGLEN_LEN;
ti = proto_tree_add_item(tree, hf_moldudp64_msgblk,
tvb, offset, whole_len, ENC_NA);
blk_tree = proto_item_add_subtree(ti, ett_moldudp64_msgblk);
ti = proto_tree_add_uint64(blk_tree, hf_moldudp64_msgseq,
tvb, offset, 0, sequence);
proto_item_set_generated(ti);
ti = proto_tree_add_item(blk_tree, hf_moldudp64_msglen,
tvb, offset, MOLDUDP64_MSGLEN_LEN, ENC_BIG_ENDIAN);
if (msglen != real_msglen)
expert_add_info_format(pinfo, ti, &ei_moldudp64_msglen_invalid,
"Invalid Message Length (claimed %u, found %u)",
msglen, real_msglen);
offset += MOLDUDP64_MSGLEN_LEN;
next_tvb = tvb_new_subset_length(tvb, offset, real_msglen);
if (!dissector_try_payload_new(moldudp64_payload_table, next_tvb, pinfo, tree, FALSE, NULL))
{
proto_tree_add_item(blk_tree, hf_moldudp64_msgdata, tvb, offset, real_msglen, ENC_NA);
}
return whole_len;
}
/* Code to actually dissect the packets */
static int
dissect_moldudp64(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
proto_item *ti;
proto_tree *moldudp64_tree;
guint offset = 0;
guint16 count, real_count = 0;
guint64 sequence;
/* Check that there's enough data */
if (tvb_reported_length(tvb) < (MOLDUDP64_SESSION_LEN +
MOLDUDP64_SEQUENCE_LEN +
MOLDUDP64_COUNT_LEN))
return 0;
/* Make entries in Protocol column and Info column on summary display */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "MoldUDP64");
/* Clear the info column so it's sane if we crash. We fill it in later when
* we've dissected more of the packet. */
col_clear(pinfo->cinfo, COL_INFO);
sequence = tvb_get_ntoh64(tvb, MOLDUDP64_SESSION_LEN);
count = tvb_get_ntohs(tvb, MOLDUDP64_SESSION_LEN + MOLDUDP64_SEQUENCE_LEN);
if (count == MOLDUDP64_HEARTBEAT)
col_set_str(pinfo->cinfo, COL_INFO, "MoldUDP64 Heartbeat");
else if (count == MOLDUDP64_ENDOFSESS)
col_set_str(pinfo->cinfo, COL_INFO, "MoldUDP64 End Of Session");
else if (count > 0 && tvb_reported_length(tvb) == (MOLDUDP64_SESSION_LEN +
MOLDUDP64_SEQUENCE_LEN +
MOLDUDP64_COUNT_LEN))
col_set_str(pinfo->cinfo, COL_INFO, "MoldUDP64 Request");
else
col_set_str(pinfo->cinfo, COL_INFO, "MoldUDP64 Messages");
/* create display subtree for the protocol */
ti = proto_tree_add_item(tree, proto_moldudp64,
tvb, offset, -1, ENC_NA);
moldudp64_tree = proto_item_add_subtree(ti, ett_moldudp64);
proto_tree_add_item(moldudp64_tree, hf_moldudp64_session,
tvb, offset, MOLDUDP64_SESSION_LEN, ENC_ASCII);
offset += MOLDUDP64_SESSION_LEN;
proto_tree_add_item(moldudp64_tree, hf_moldudp64_sequence,
tvb, offset, MOLDUDP64_SEQUENCE_LEN, ENC_BIG_ENDIAN);
offset += MOLDUDP64_SEQUENCE_LEN;
ti = proto_tree_add_item(moldudp64_tree, hf_moldudp64_count,
tvb, offset, MOLDUDP64_COUNT_LEN, ENC_BIG_ENDIAN);
offset += MOLDUDP64_COUNT_LEN;
while (tvb_reported_length(tvb) >= offset + MOLDUDP64_MSGLEN_LEN)
{
offset += dissect_moldudp64_msgblk(tvb, pinfo, moldudp64_tree,
offset, sequence++);
real_count++;
}
if (count == MOLDUDP64_ENDOFSESS && real_count != 0)
{
expert_add_info(pinfo, ti, &ei_moldudp64_end_of_session_extra);
}
else if (count > 0 && real_count == 0)
{
expert_add_info(pinfo, ti, &ei_moldudp64_request);
}
else if (real_count != count)
{
expert_add_info_format(pinfo, ti, &ei_moldudp64_count_invalid,
"Invalid Message Count (claimed %u, found %u)",
count, real_count);
}
/* Return the amount of data this dissector was able to dissect */
return tvb_captured_length(tvb);
}
/* Register the protocol with Wireshark */
void
proto_register_moldudp64(void)
{
/* Setup list of header fields */
static hf_register_info hf[] = {
{ &hf_moldudp64_session,
{ "Session", "moldudp64.session", FT_STRING, BASE_NONE, NULL, 0,
"The session to which this packet belongs.", HFILL }},
{ &hf_moldudp64_sequence,
{ "Sequence", "moldudp64.sequence", FT_UINT64, BASE_DEC, NULL, 0,
"The sequence number of the first message in this packet.", HFILL }},
{ &hf_moldudp64_count,
{ "Count", "moldudp64.count", FT_UINT16, BASE_DEC, NULL, 0,
"The number of messages contained in this packet.", HFILL }},
{ &hf_moldudp64_msgblk,
{ "Message Block", "moldudp64.msgblock", FT_NONE, BASE_NONE, NULL, 0,
"A message.", HFILL }},
{ &hf_moldudp64_msglen,
{ "Length", "moldudp64.msglen", FT_UINT16, BASE_DEC, NULL, 0,
"The length of this message.", HFILL }},
{ &hf_moldudp64_msgseq,
{ "Sequence", "moldudp64.msgseq", FT_UINT64, BASE_DEC, NULL, 0,
"The sequence number of this message.", HFILL }},
{ &hf_moldudp64_msgdata,
{ "Payload", "moldudp64.msgdata", FT_BYTES, BASE_NONE, NULL, 0,
"The payload data of this message.", HFILL }}
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_moldudp64,
&ett_moldudp64_msgblk
};
static ei_register_info ei[] = {
{ &ei_moldudp64_msglen_invalid, { "moldudp64.msglen.invalid", PI_MALFORMED, PI_ERROR, "Invalid Message Length", EXPFILL }},
{ &ei_moldudp64_end_of_session_extra, { "moldudp64.end_of_session_extra", PI_MALFORMED, PI_ERROR, "End Of Session packet with extra data.", EXPFILL }},
{ &ei_moldudp64_count_invalid, { "moldudp64.count.invalid", PI_MALFORMED, PI_ERROR, "Invalid Message Count", EXPFILL }},
{ &ei_moldudp64_request, { "moldudp64.request", PI_COMMENTS_GROUP, PI_COMMENT, "Number of Requested Messages", EXPFILL }},
};
expert_module_t* expert_moldudp64;
/* Register the protocol name and description */
proto_moldudp64 = proto_register_protocol("MoldUDP64",
"MoldUDP64", "moldudp64");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_moldudp64, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_moldudp64 = expert_register_protocol(proto_moldudp64);
expert_register_field_array(expert_moldudp64, ei, array_length(ei));
moldudp64_payload_table = register_decode_as_next_proto(proto_moldudp64, "moldudp64.payload",
"MoldUDP64 Payload", moldudp64_prompt);
}
void
proto_reg_handoff_moldudp64(void)
{
dissector_handle_t moldudp64_handle;
moldudp64_handle = create_dissector_handle(dissect_moldudp64, proto_moldudp64);
dissector_add_for_decode_as_with_preference("udp.port", moldudp64_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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