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/* packet-pw-eth.c
* Routines for ethernet PW dissection: it should conform to RFC 4448.
*
* Copyright 2008 _FF_
*
* Francesco Fondelli <francesco dot fondelli, gmail dot 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/addr_resolv.h>
#include "packet-mpls.h"
void proto_register_pw_eth(void);
void proto_reg_handoff_pw_eth(void);
static gint proto_pw_eth_cw = -1;
static gint proto_pw_eth_nocw = -1;
static gint proto_pw_eth_heuristic = -1;
static gint ett_pw_eth = -1;
static int hf_pw_eth = -1;
static int hf_pw_eth_cw = -1;
static int hf_pw_eth_cw_sequence_number = -1;
static dissector_handle_t eth_withoutfcs_handle;
static dissector_handle_t pw_eth_handle_cw;
static dissector_handle_t pw_eth_handle_nocw;
static dissector_handle_t pw_eth_handle_heuristic;
static int
dissect_pw_eth_cw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
tvbuff_t *next_tvb;
guint16 sequence_number;
if (tvb_reported_length_remaining(tvb, 0) < 4) {
return 0;
}
if (dissect_try_cw_first_nibble(tvb, pinfo, tree))
return tvb_captured_length(tvb);
sequence_number = tvb_get_ntohs(tvb, 2);
if (tree) {
proto_tree *pw_eth_tree;
proto_item *ti;
ti = proto_tree_add_boolean(tree, hf_pw_eth_cw,
tvb, 0, 0, TRUE);
proto_item_set_hidden(ti);
ti = proto_tree_add_item(tree, proto_pw_eth_cw,
tvb, 0, 4, ENC_NA);
pw_eth_tree = proto_item_add_subtree(ti, ett_pw_eth);
proto_tree_add_uint_format(pw_eth_tree,
hf_pw_eth_cw_sequence_number,
tvb, 2, 2, sequence_number,
"Sequence Number: %d",
sequence_number);
}
next_tvb = tvb_new_subset_remaining(tvb, 4);
{
call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
}
return tvb_captured_length(tvb);
}
static int
dissect_pw_eth_nocw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
tvbuff_t *next_tvb;
if (tree) {
proto_item *ti;
ti = proto_tree_add_boolean(tree, hf_pw_eth, tvb, 0, 0, TRUE);
proto_item_set_hidden(ti);
}
next_tvb = tvb_new_subset_remaining(tvb, 0);
call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
return tvb_captured_length(tvb);
}
/*
* FF: this function returns TRUE if the first 12 bytes in tvb looks like
* two valid ethernet addresses. FALSE otherwise.
*/
static gboolean
looks_like_plain_eth(tvbuff_t *tvb _U_)
{
const gchar *manuf_name_da;
const gchar *manuf_name_sa;
if (tvb_reported_length_remaining(tvb, 0) < 14) {
return FALSE;
}
manuf_name_da = tvb_get_manuf_name_if_known(tvb, 0);
manuf_name_sa = tvb_get_manuf_name_if_known(tvb, 6);
if (manuf_name_da && manuf_name_sa) {
return TRUE;
}
return FALSE;
}
static int
dissect_pw_eth_heuristic(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
guint8 first_nibble = (tvb_get_guint8(tvb, 0) >> 4) & 0x0F;
if (looks_like_plain_eth(tvb))
call_dissector(pw_eth_handle_nocw, tvb, pinfo, tree);
else if (first_nibble == 0)
call_dissector(pw_eth_handle_cw, tvb, pinfo, tree);
else
call_dissector(pw_eth_handle_nocw, tvb, pinfo, tree);
return tvb_captured_length(tvb);
}
void
proto_register_pw_eth(void)
{
static hf_register_info hf[] = {
{
&hf_pw_eth,
{
"PW (ethernet)",
"pweth", FT_BOOLEAN,
BASE_NONE, NULL, 0x0, NULL, HFILL
}
},
{
&hf_pw_eth_cw,
{
"PW Control Word (ethernet)",
"pweth.cw", FT_BOOLEAN,
BASE_NONE, NULL, 0x0, NULL, HFILL
}
},
{
&hf_pw_eth_cw_sequence_number,
{
"PW sequence number (ethernet)",
"pweth.cw.sequence_number", FT_UINT16,
BASE_DEC, NULL, 0x0, NULL, HFILL
}
}
};
static gint *ett[] = {
&ett_pw_eth
};
proto_pw_eth_cw =
proto_register_protocol("PW Ethernet Control Word",
"Ethernet PW (with CW)",
"pwethcw");
proto_pw_eth_nocw =
proto_register_protocol("Ethernet PW (no CW)", /* not displayed */
"Ethernet PW (no CW)",
"pwethnocw");
proto_pw_eth_heuristic =
proto_register_protocol("Ethernet PW (CW heuristic)", /* not disp. */
"Ethernet PW (CW heuristic)",
"pwethheuristic");
proto_register_field_array(proto_pw_eth_cw, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
pw_eth_handle_cw = register_dissector("pw_eth_cw", dissect_pw_eth_cw, proto_pw_eth_cw);
pw_eth_handle_nocw = register_dissector("pw_eth_nocw", dissect_pw_eth_nocw, proto_pw_eth_nocw);
pw_eth_handle_heuristic = register_dissector("pw_eth_heuristic", dissect_pw_eth_heuristic,
proto_pw_eth_heuristic);
}
void
proto_reg_handoff_pw_eth(void)
{
eth_withoutfcs_handle = find_dissector_add_dependency("eth_withoutfcs", proto_pw_eth_cw);
dissector_add_for_decode_as("mpls.label", pw_eth_handle_cw);
dissector_add_for_decode_as("mpls.label", pw_eth_handle_nocw);
dissector_add_for_decode_as("mpls.label", pw_eth_handle_heuristic);
}
/*
* 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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