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/* packet-pw-eth.c
* Routines for ethernet PW dissection: it should be conform to RFC 4448.
*
* Copyright 2008 _FF_
*
* Francesco Fondelli <francesco dot fondelli, gmail dot com>
*
* $Id$
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdlib.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/addr_resolv.h>
#include "packet-mpls.h"
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 void
dissect_pw_eth_cw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_tree *pw_eth_tree = NULL;
proto_item *ti = NULL;
tvbuff_t *next_tvb = NULL;
guint16 sequence_number = 0;
if (tvb_reported_length_remaining(tvb, 0) < 4) {
if (tree)
proto_tree_add_text(tree, tvb, 0, -1,
"Error processing Message");
return;
}
if (dissect_try_cw_first_nibble(tvb, pinfo, tree))
return;
sequence_number = tvb_get_ntohs(tvb, 2);
if (tree) {
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);
if (pw_eth_tree == NULL)
return;
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);
{
/*
* When Ethernet frames being decoded, pinfo->ethertype is extracted
* from the top-level Ethernet frame. Dissection of Ethernet PW payload
* overwrites this value as the same dissector is invoked again.
* This may lead to undesired behavior (like disappearance of "Link"
* tab from the "Decode as" menu).
*
* Let's save/restore ethertype. --ATA
*
* XXX it looks that more pinfo members (or even the whole pinfo)
* XXX should be saved/restored in PW cases. Multilayer encapsulations,
* XXX like ethernet/mpls/ethernet-pw/ip/vlan, may lead to undesired
* XXX changes if pinfo->ipproto, ptype etc.
*/
guint32 etype_save = pinfo->ethertype;
call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
pinfo->ethertype = etype_save;
}
}
static void
dissect_pw_eth_nocw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
tvbuff_t *next_tvb = NULL;
proto_item *ti = NULL;
if (tree) {
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);
{
guint32 etype_save = pinfo->ethertype;
call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
pinfo->ethertype = etype_save;
}
}
/*
* 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 = NULL;
const gchar *manuf_name_sa = NULL;
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 void
dissect_pw_eth_heuristic(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
if (looks_like_plain_eth(tvb)) {
call_dissector(pw_eth_handle_nocw, tvb, pinfo, tree);
} else {
call_dissector(pw_eth_handle_cw, tvb, pinfo, tree);
}
}
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));
register_dissector("pw_eth_cw", dissect_pw_eth_cw, proto_pw_eth_cw);
register_dissector("pw_eth_nocw", dissect_pw_eth_nocw,
proto_pw_eth_nocw);
register_dissector("pw_eth_heuristic", dissect_pw_eth_heuristic,
proto_pw_eth_heuristic);
}
void
proto_reg_handoff_pw_eth(void)
{
dissector_handle_t pw_eth_handle_heuristic;
eth_withoutfcs_handle = find_dissector("eth_withoutfcs");
pw_eth_handle_cw = find_dissector("pw_eth_cw");
dissector_add_uint("mpls.label", LABEL_INVALID, pw_eth_handle_cw);
pw_eth_handle_nocw = find_dissector("pw_eth_nocw");
dissector_add_uint("mpls.label", LABEL_INVALID, pw_eth_handle_nocw);
pw_eth_handle_heuristic = find_dissector("pw_eth_heuristic");
dissector_add_uint("mpls.label", LABEL_INVALID, pw_eth_handle_heuristic);
}
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