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wireshark/epan/dissectors/packet-gvrp.c

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/* packet-gvrp.c
* Routines for GVRP (GARP VLAN Registration Protocol) dissection
* Copyright 2000, Kevin Shi <techishi@ms22.hinet.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 <epan/expert.h>
void proto_register_gvrp(void);
/* Initialize the protocol and registered fields */
static int proto_gvrp = -1;
static int hf_gvrp_proto_id = -1;
static int hf_gvrp_attribute_type = -1;
static int hf_gvrp_attribute_length = -1;
static int hf_gvrp_attribute_event = -1;
static int hf_gvrp_attribute_value = -1;
static int hf_gvrp_end_of_mark = -1;
/* Initialize the subtree pointers */
static gint ett_gvrp = -1;
static gint ett_gvrp_message = -1;
static gint ett_gvrp_attribute = -1;
static expert_field ei_gvrp_proto_id = EI_INIT;
/* Constant definitions */
#define GARP_DEFAULT_PROTOCOL_ID 0x0001
#define GARP_END_OF_MARK 0x00
#define GVRP_ATTRIBUTE_TYPE 0x01
static const value_string attribute_type_vals[] = {
{ GVRP_ATTRIBUTE_TYPE, "VID" },
{ 0, NULL }
};
/* The length of GVRP LeaveAll attribute should be 2 octets (one for length
* and the other for event) */
#define GVRP_LENGTH_LEAVEALL (int)(sizeof(guint8)+sizeof(guint8))
/* The length of GVRP attribute other than LeaveAll should be 4 octets (one
* for length, one for event, and the last two for VID value).
*/
#define GVRP_LENGTH_NON_LEAVEALL (int)(sizeof(guint8)+sizeof(guint8)+sizeof(guint16))
/* Packet offset definitions */
#define GARP_PROTOCOL_ID 0
/* Event definitions */
#define GVRP_EVENT_LEAVEALL 0
#define GVRP_EVENT_JOINEMPTY 1
#define GVRP_EVENT_JOININ 2
#define GVRP_EVENT_LEAVEEMPTY 3
#define GVRP_EVENT_LEAVEIN 4
#define GVRP_EVENT_EMPTY 5
static const value_string event_vals[] = {
{ GVRP_EVENT_LEAVEALL, "Leave All" },
{ GVRP_EVENT_JOINEMPTY, "Join Empty" },
{ GVRP_EVENT_JOININ, "Join In" },
{ GVRP_EVENT_LEAVEEMPTY, "Leave Empty" },
{ GVRP_EVENT_LEAVEIN, "Leave In" },
{ GVRP_EVENT_EMPTY, "Empty" },
{ 0, NULL }
};
/* Code to actually dissect the packets */
static int
dissect_gvrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_item *ti, *id_item;
proto_tree *gvrp_tree, *msg_tree, *attr_tree;
guint16 protocol_id;
guint8 octet;
int msg_index;
int attr_index;
int offset = 0;
int length = tvb_reported_length(tvb);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "GVRP");
col_set_str(pinfo->cinfo, COL_INFO, "GVRP");
ti = proto_tree_add_item(tree, proto_gvrp, tvb, 0, length, ENC_NA);
gvrp_tree = proto_item_add_subtree(ti, ett_gvrp);
/* Read in GARP protocol ID */
protocol_id = tvb_get_ntohs(tvb, GARP_PROTOCOL_ID);
id_item = proto_tree_add_uint_format_value(gvrp_tree, hf_gvrp_proto_id, tvb,
GARP_PROTOCOL_ID, 2,
protocol_id,
"0x%04x (%s)",
protocol_id,
protocol_id == GARP_DEFAULT_PROTOCOL_ID ?
"GARP VLAN Registration Protocol" :
"Unknown Protocol");
/* Currently only one protocol ID is supported */
if (protocol_id != GARP_DEFAULT_PROTOCOL_ID)
{
expert_add_info(pinfo, id_item, &ei_gvrp_proto_id);
call_data_dissector(tvb_new_subset_remaining(tvb, GARP_PROTOCOL_ID + 2),
pinfo, tree);
return tvb_captured_length(tvb);
}
offset += 2;
length -= 2;
msg_index = 0;
/* Begin to parse GARP messages */
while (length)
{
proto_item *msg_item;
int msg_start = offset;
/* Read in attribute type. */
octet = tvb_get_guint8(tvb, offset);
/* Check for end of mark */
if (octet == GARP_END_OF_MARK)
{
/* End of GARP PDU */
if (msg_index)
{
proto_tree_add_item(gvrp_tree, hf_gvrp_end_of_mark, tvb, offset, 1, ENC_NA);
break;
}
else
{
call_data_dissector(tvb_new_subset_remaining(tvb, offset), pinfo, tree);
return tvb_captured_length(tvb);
}
}
offset += 1;
length -= 1;
msg_tree = proto_tree_add_subtree_format(gvrp_tree, tvb, msg_start, -1, ett_gvrp_message, &msg_item,
"Message %d", msg_index + 1);
proto_tree_add_uint(msg_tree, hf_gvrp_attribute_type, tvb,
msg_start, 1, octet);
/* GVRP only supports one attribute type. */
if (octet != GVRP_ATTRIBUTE_TYPE)
{
call_data_dissector(tvb_new_subset_remaining(tvb, offset),
pinfo, tree);
return tvb_captured_length(tvb);
}
attr_index = 0;
while (length)
{
int attr_start = offset;
proto_item *attr_item;
/* Read in attribute length. */
octet = tvb_get_guint8(tvb, offset);
/* Check for end of mark */
if (octet == GARP_END_OF_MARK)
{
/* If at least one message has been already read,
* check for another end of mark.
*/
if (attr_index)
{
proto_tree_add_item(msg_tree, hf_gvrp_end_of_mark, tvb, offset, 1, ENC_NA);
offset += 1;
length -= 1;
proto_item_set_len(msg_item, offset - msg_start);
break;
}
else
{
call_data_dissector(tvb_new_subset_remaining(tvb, offset), pinfo, tree);
return tvb_captured_length(tvb);
}
}
else
{
guint8 event;
offset += 1;
length -= 1;
attr_tree = proto_tree_add_subtree_format(msg_tree, tvb, attr_start, -1,
ett_gvrp_attribute, &attr_item, "Attribute %d", attr_index + 1);
proto_tree_add_uint(attr_tree, hf_gvrp_attribute_length,
tvb, attr_start, 1, octet);
/* Read in attribute event */
event = tvb_get_guint8(tvb, offset);
proto_tree_add_uint(attr_tree, hf_gvrp_attribute_event,
tvb, offset, 1, event);
offset += 1;
length -= 1;
switch (event) {
case GVRP_EVENT_LEAVEALL:
if (octet != GVRP_LENGTH_LEAVEALL)
{
call_data_dissector(tvb_new_subset_remaining(tvb, offset), pinfo,
tree);
return tvb_captured_length(tvb);
}
break;
case GVRP_EVENT_JOINEMPTY:
case GVRP_EVENT_JOININ:
case GVRP_EVENT_LEAVEEMPTY:
case GVRP_EVENT_LEAVEIN:
case GVRP_EVENT_EMPTY:
if (octet != GVRP_LENGTH_NON_LEAVEALL)
{
call_data_dissector(tvb_new_subset_remaining(tvb, offset),pinfo,
tree);
return tvb_captured_length(tvb);
}
/* Show attribute value */
proto_tree_add_item(attr_tree, hf_gvrp_attribute_value,
tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
length -= 2;
break;
default:
call_data_dissector(tvb_new_subset_remaining(tvb, offset), pinfo, tree);
return tvb_captured_length(tvb);
}
}
proto_item_set_len(attr_item, offset - attr_start);
attr_index++;
}
msg_index++;
}
return tvb_captured_length(tvb);
}
/* Register the protocol with Wireshark */
void
proto_register_gvrp(void)
{
static hf_register_info hf[] = {
{ &hf_gvrp_proto_id,
{ "Protocol Identifier", "gvrp.protocol_id",
FT_UINT16, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_gvrp_attribute_type,
{ "Type", "gvrp.attribute_type",
FT_UINT8, BASE_HEX, VALS(attribute_type_vals), 0x0,
NULL, HFILL }
},
{ &hf_gvrp_attribute_length,
{ "Length", "gvrp.attribute_length",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_gvrp_attribute_event,
{ "Event", "gvrp.attribute_event",
FT_UINT8, BASE_DEC, VALS(event_vals), 0x0,
NULL, HFILL }
},
{ &hf_gvrp_attribute_value,
{ "Value", "gvrp.attribute_value",
FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL },
},
{ &hf_gvrp_end_of_mark,
{ "End of Mark", "gvrp.end_of_mark",
FT_NONE, BASE_NONE, NULL, 0x0,
NULL, HFILL },
},
};
static ei_register_info ei[] = {
{ &ei_gvrp_proto_id, { "gvrp.protocol_id.unknown", PI_PROTOCOL, PI_WARN, "Warning: this version of Wireshark only knows about protocol id = 1", EXPFILL }},
};
expert_module_t* expert_gvrp;
static gint *ett[] = {
&ett_gvrp,
&ett_gvrp_message,
&ett_gvrp_attribute,
};
/* Register the protocol name and description for GVRP */
proto_gvrp = proto_register_protocol("GARP VLAN Registration Protocol", "GVRP", "gvrp");
/* Required function calls to register the header fields and subtrees
* used by GVRP */
proto_register_field_array(proto_gvrp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_gvrp = expert_register_protocol(proto_gvrp);
expert_register_field_array(expert_gvrp, ei, array_length(ei));
register_dissector("gvrp", dissect_gvrp, proto_gvrp);
}
/*
* 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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