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/* packet-laplink.c
* Routines for laplink dissection
* Copyright 2003, Brad Hards <bradh@frogmouth.net>
*
* 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 "packet-tcp.h"
#include <epan/prefs.h>
void proto_register_laplink(void);
void proto_reg_handoff_laplink(void);
static dissector_handle_t laplink_udp_handle;
static dissector_handle_t laplink_tcp_handle;
#define TCP_PORT_LAPLINK 1547
#define UDP_PORT_LAPLINK 1547
/* Initialize the protocol and registered fields */
static int proto_laplink;
static int hf_laplink_udp_ident;
static int hf_laplink_udp_name;
static int hf_laplink_tcp_ident;
static int hf_laplink_tcp_length;
static int hf_laplink_tcp_data;
/* Initialize the subtree pointers */
static int ett_laplink;
static const value_string laplink_udp_magic[] = {
{ 0x0f010000, "Name Solicitation" },
{ 0xf0000200, "Name Reply" },
{ 0, NULL }
};
static const value_string laplink_tcp_magic[] = {
{ 0xff08c000, "Unknown TCP query - connection?" },
{ 0xff08c200, "Unknown TCP query - connection?" },
{ 0xff0bc000, "Unknown TCP query - connection?" },
{ 0xff0bc200, "Unknown TCP query - connection?" },
{ 0xff10c000, "Unknown TCP response - connection?" },
{ 0xff10c200, "Unknown TCP response - connection?" },
{ 0xff11c000, "Unknown TCP query/response - directory list or file transfer?" },
{ 0xff11c200, "Unknown TCP query - directory list or file request?" },
{ 0xff13c000, "Unknown TCP response - connection?" },
{ 0xff13c200, "Unknown TCP response - connection?" },
{ 0xff14c000, "Unknown TCP response - directory list or file transfer?" },
{ 0, NULL }
};
static bool laplink_desegment = true;
/* Code to actually dissect the packets - UDP */
static int
dissect_laplink_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
int offset = 0;
proto_item *ti;
proto_tree *laplink_tree;
uint32_t udp_ident;
const char *udp_ident_string;
/*
* Make sure the identifier is reasonable.
*/
if (!tvb_bytes_exist(tvb, offset, 4))
return 0; /* not enough bytes to check */
udp_ident = tvb_get_ntohl(tvb, offset);
udp_ident_string = try_val_to_str(udp_ident, laplink_udp_magic);
if (udp_ident_string == NULL)
return 0; /* unknown */
/* Make entries in Protocol column and Info column on summary display */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "Laplink");
col_add_str(pinfo->cinfo, COL_INFO, udp_ident_string);
if (tree){
ti = proto_tree_add_item(tree, proto_laplink, tvb, 0, -1, ENC_NA);
laplink_tree = proto_item_add_subtree(ti, ett_laplink);
proto_tree_add_uint(laplink_tree, hf_laplink_udp_ident, tvb, offset, 4, udp_ident);
offset += 4;
proto_tree_add_item(laplink_tree, hf_laplink_udp_name, tvb, offset, -1, ENC_ASCII);
}
return tvb_captured_length(tvb);
}
/* Code to actually dissect the packets - TCP aspects*/
static int
dissect_laplink_tcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
int offset = 0;
int length = 0;
proto_item *ti;
proto_tree *laplink_tree;
uint32_t tcp_ident;
/* Make entries in Protocol column and Info column on summary display */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "Laplink");
tcp_ident = tvb_get_ntohl(tvb, offset);
col_add_str(pinfo->cinfo, COL_INFO,
val_to_str(tcp_ident, laplink_tcp_magic, "TCP TBA (%u)"));
if (tree){
ti = proto_tree_add_item(tree, proto_laplink, tvb, 0, -1, ENC_NA);
laplink_tree = proto_item_add_subtree(ti, ett_laplink);
proto_tree_add_item(laplink_tree, hf_laplink_tcp_ident, tvb, offset, 4, ENC_BIG_ENDIAN);
offset += 4;
length = tvb_get_ntohs(tvb, offset);
proto_tree_add_item(laplink_tree, hf_laplink_tcp_length, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(laplink_tree, hf_laplink_tcp_data, tvb, offset, length, ENC_NA);
/* Continue adding tree items to process the packet here */
}
return tvb_captured_length(tvb);
/* If this protocol has a sub-dissector call it here, see section 1.8 */
}
static unsigned
get_laplink_pdu_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)
{
unsigned plen;
/*
* The length doesn't include the length or ident fields; add those in.
*/
plen = (tvb_get_ntohs(tvb, offset+4) + 2 + 4);
return plen;
}
static int
dissect_laplink_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
tcp_dissect_pdus(tvb, pinfo, tree, laplink_desegment,
6, get_laplink_pdu_len,
dissect_laplink_tcp_pdu, data);
return tvb_captured_length(tvb);
}
/* Register the protocol with Wireshark */
void
proto_register_laplink(void)
{
/* Setup list of header fields See Section 1.6.1 for details*/
static hf_register_info hf[] = {
{ &hf_laplink_udp_ident,
{ "UDP Ident", "laplink.udp_ident",
FT_UINT32, BASE_HEX, VALS(laplink_udp_magic), 0x0,
"Unknown magic", HFILL }
},
{ &hf_laplink_udp_name,
{ "UDP Name", "laplink.udp_name",
FT_STRINGZ, BASE_NONE, NULL, 0x0,
"Machine name", HFILL }
},
{ &hf_laplink_tcp_ident,
{ "TCP Ident", "laplink.tcp_ident",
FT_UINT32, BASE_HEX, VALS(laplink_tcp_magic), 0x0,
"Unknown magic", HFILL }
},
{ &hf_laplink_tcp_length,
{ "TCP Data payload length", "laplink.tcp_length",
FT_UINT16, BASE_DEC, NULL, 0x0,
"Length of remaining payload", HFILL }
},
{ &hf_laplink_tcp_data,
{ "Unknown TCP data", "laplink.tcp_data",
FT_BYTES, BASE_NONE, NULL, 0x0,
NULL, HFILL }
},
};
/* Setup protocol subtree array */
static int *ett[] = {
&ett_laplink,
};
module_t *laplink_module;
/* Register the protocol name and description */
proto_laplink = proto_register_protocol("Laplink", "Laplink", "laplink");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_laplink, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
laplink_module = prefs_register_protocol(proto_laplink, NULL);
prefs_register_bool_preference(laplink_module, "desegment_laplink_over_tcp",
"Reassemble Laplink over TCP messages spanning multiple TCP segments",
"Whether the Laplink dissector should reassemble messages spanning multiple TCP segments."
" To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
&laplink_desegment);
laplink_tcp_handle = register_dissector("laplink.tcp", dissect_laplink_tcp, proto_laplink);
laplink_udp_handle = register_dissector("laplink.udp", dissect_laplink_udp, proto_laplink);
}
/* If this dissector uses sub-dissector registration add a registration routine.
This format is required because a script is used to find these routines and
create the code that calls these routines.
*/
void
proto_reg_handoff_laplink(void)
{
dissector_add_uint_with_preference("tcp.port", TCP_PORT_LAPLINK, laplink_tcp_handle);
dissector_add_uint_with_preference("udp.port", UDP_PORT_LAPLINK, laplink_udp_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:
*/
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