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wireshark/packet-fr.c

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/* packet-fr.c
* Routines for Frame Relay dissection
*
* Copyright 2001, Paul Ionescu <paul@acorp.ro>
*
* $Id: packet-fr.c,v 1.7 2001/01/13 07:47:48 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.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 <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <glib.h>
#include "packet.h"
#include "packet-llc.h"
#include "xdlc.h"
#include "oui.h"
#include "nlpid.h"
#include "greproto.h"
static gint proto_fr = -1;
static gint ett_fr = -1;
static gint hf_fr_dlci = -1;
static gint hf_fr_cr = -1;
static gint hf_fr_becn = -1;
static gint hf_fr_fecn = -1;
static gint hf_fr_de = -1;
static gint hf_fr_nlpid = -1;
static gint hf_fr_oui = -1;
static gint hf_fr_pid = -1;
static gint hf_fr_type = -1;
static dissector_table_t fr_subdissector_table;
static dissector_table_t fr_cisco_subdissector_table;
static void dissect_lapf(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
static void dissect_fr_xid(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
/* see RFC2427 / RFC1490 and Cisco encapsulation */
static void dissect_fr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *ti;
proto_tree *fr_tree = NULL;
guint16 fr_header,fr_type,offset=2; /* default header length of FR is 2 bytes */
guint8 fr_nlpid,fr_ctrl;
CHECK_DISPLAY_AS_DATA(proto_fr, tvb, pinfo, tree);
pinfo->current_proto = "Frame Relay";
if (check_col(pinfo->fd, COL_PROTOCOL))
col_set_str(pinfo->fd, COL_PROTOCOL, "FR");
if (check_col(pinfo->fd, COL_INFO))
col_clear(pinfo->fd, COL_INFO);
fr_header = tvb_get_ntohs( tvb, 0 );
if (check_col(pinfo->fd, COL_INFO))
col_add_fstr(pinfo->fd, COL_INFO, "DLCI %u",
((fr_header&0x00FF)>>4)+((fr_header&0xFC00)>>6));
fr_header = tvb_get_ntohs( tvb, 0 );
fr_ctrl = tvb_get_guint8( tvb,offset);
if (tree) {
ti = proto_tree_add_protocol_format(tree, proto_fr, tvb, 0, 4, "Frame Relay");
fr_tree = proto_item_add_subtree(ti, ett_fr);
proto_tree_add_text(fr_tree,tvb,0,2,"The real DLCI is %u",((fr_header&0x00FF)>>4)+((fr_header&0xFC00)>>6));
proto_tree_add_uint(fr_tree, hf_fr_dlci, tvb, 0, 2, fr_header);
proto_tree_add_boolean(fr_tree, hf_fr_cr, tvb, 0, 1, fr_header);
proto_tree_add_boolean(fr_tree, hf_fr_fecn, tvb, 1, 1, fr_header);
proto_tree_add_boolean(fr_tree, hf_fr_becn, tvb, 1, 1, fr_header);
proto_tree_add_boolean(fr_tree, hf_fr_de, tvb, 1, 1, fr_header);
}
if (fr_ctrl == XDLC_U) {
if (tree) {
proto_tree_add_text(fr_tree, tvb, offset, 0, "------- IETF Encapsulation -------");
/*
* XXX - if we're going to show this as Unnumbered
* Information, should we just hand it to
* "dissect_xdlc_control()"?
*/
proto_tree_add_text(fr_tree, tvb, offset, 1, "Unnumbered Information");
}
offset++;
fr_nlpid = tvb_get_guint8 (tvb,offset);
if (fr_nlpid == 0) {
if (tree)
proto_tree_add_text(fr_tree, tvb, offset, 1, "Padding");
offset++;
fr_nlpid=tvb_get_guint8( tvb,offset);
}
if (tree)
proto_tree_add_uint(fr_tree, hf_fr_nlpid, tvb, offset, 1, fr_nlpid );
offset++;
if (fr_nlpid == NLPID_SNAP) {
dissect_snap(tvb, offset, pinfo, tree, fr_tree, fr_ctrl,
hf_fr_oui, hf_fr_type, hf_fr_pid, 0);
return;
}
/*
* XXX - we should just call "dissect_osi()" here, but
* some of the routines "dissect_osi()" calls themselves put
* the NLPID into the tree, and not everything registered with
* "fr.ietf" is also registered with "osinl".
*
* We'd need to figure out what to do with the NLPID.
* "dissect_osi()" is registered with the "llc.dsap" dissector
* table, so if it were to put the NLPID into the protocol
* tree it'd have to create its own subtree for it - not all its
* callers can do that for it (without knowing whether they're
* going to call it or not, and the LLC dissector doesn't).
*
* Currently, it hands the NLPID as part of the tvbuff to
* the sub-dissectors it calls; if none of them need to look
* at it, we could perhaps have it put the NLPID into the
* tree and *not* have the subdissectors expect it - that's
* what would have to be done for IP, for example, as IP,
* unlike CLNP, doesn't expect an NLPID as the first byte.
*/
if (!dissector_try_port(fr_subdissector_table,fr_nlpid, tvb_new_subset(tvb,offset,-1,-1), pinfo, tree))
dissect_data(tvb_new_subset(tvb,offset,-1,-1), 0, pinfo, tree);
return;
} else {
if ((fr_header && 0xFCF0) == 0) {
/* this must be some sort of lapf on DLCI 0 for SVC */
/* because DLCI 0 is rezerved for LMI and SVC signaling encaplulated in lapf */
/* and LMI is transmitted in unnumbered information (03) */
/* so this must be lapf (guessing) */
dissect_lapf(tvb_new_subset(tvb,offset,-1,-1),pinfo,tree);
return;
}
if (fr_ctrl == (XDLC_U|XDLC_XID)) {
dissect_fr_xid(tvb_new_subset(tvb,offset,-1,-1),pinfo,tree);
return;
}
/*
* If the data does not start with unnumbered information (03) and
* the DLCI# is not 0, then there may be Cisco Frame Relay encapsulation.
*/
proto_tree_add_text(fr_tree, tvb, offset, 0, "------- Cisco Encapsulation -------");
fr_type = tvb_get_ntohs( tvb, offset);
proto_tree_add_uint(fr_tree, hf_fr_type,tvb, offset, 2, fr_type );
if (!dissector_try_port(fr_cisco_subdissector_table,fr_type, tvb_new_subset(tvb,offset+2,-1,-1), pinfo, tree))
dissect_data(tvb_new_subset(tvb,offset+2,-1,-1), offset+2, pinfo, tree);
}
}
static void dissect_lapf(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_tree_add_text(tree, tvb, 0, 0, "Frame relay lapf not yet implemented");
dissect_data(tvb_new_subset(tvb,0,-1,-1),0,pinfo,tree);
}
static void dissect_fr_xid(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_tree_add_text(tree, tvb, 0, 0, "Frame relay xid not yet implemented");
dissect_data(tvb_new_subset(tvb,0,-1,-1),0,pinfo,tree);
}
/* Register the protocol with Ethereal */
void proto_register_fr(void)
{
static hf_register_info hf[] = {
{ &hf_fr_dlci, {
"DLCI", "fr.dlci", FT_UINT16, BASE_DEC,
NULL, 0xFCF0, "Data-Link Connection Identifier" }},
{ &hf_fr_cr, {
"CR", "fr.cr", FT_BOOLEAN, 16,
NULL, 0x0200, "Command/Response" }},
{ &hf_fr_fecn, {
"FECN", "fr.fecn", FT_BOOLEAN, 16,
NULL, 0x0008, "Forward Explicit Congestion Notification" }},
{ &hf_fr_becn, {
"BECN", "fr.becn", FT_BOOLEAN, 16,
NULL, 0x0004, "Backward Explicit Congestion Notification" }},
{ &hf_fr_de, {
"DE", "fr.de", FT_BOOLEAN, 16,
NULL, 0x0002, "Discard Eligibility" }},
{ &hf_fr_nlpid, {
"NLPID", "fr.nlpid", FT_UINT8, BASE_HEX,
NULL, 0x0, "FrameRelay Encapsulated Protocol NLPID" }},
{ &hf_fr_oui, {
"Organization Code", "fr.snap.oui", FT_UINT24, BASE_HEX,
VALS(oui_vals), 0x0, ""}},
{ &hf_fr_pid, {
"Protocol ID", "fr.snap.pid", FT_UINT16, BASE_HEX,
NULL, 0x0, ""}},
{ &hf_fr_type, {
"Type", "fr.type", FT_UINT16, BASE_HEX,
NULL, 0x0, "FrameRelay SNAP Encapsulated Protocol" }},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_fr,
};
proto_fr = proto_register_protocol("Frame Relay", "FR", "fr");
proto_register_field_array(proto_fr, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
fr_subdissector_table = register_dissector_table("fr.ietf");
fr_cisco_subdissector_table = register_dissector_table("fr.cisco");
}
void proto_reg_handoff_fr(void)
{
dissector_add("wtap_encap", WTAP_ENCAP_FRELAY, dissect_fr, proto_fr);
dissector_add("gre.proto", GRE_FR, dissect_fr, proto_fr);
}
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