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wireshark/packet-chdlc.c

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/* packet-chdlc.c
* Routines for Cisco HDLC packet disassembly
*
* $Id: packet-chdlc.c,v 1.21 2003/10/25 07:17:26 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* 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 <glib.h>
#include <epan/packet.h>
#include "etypes.h"
#include "prefs.h"
#include "chdlctypes.h"
#include <epan/resolv.h>
#include "packet-chdlc.h"
#include "packet-ppp.h"
#include "packet-ip.h"
/*
* See section 4.3.1 of RFC 1547, and
*
* http://www.nethelp.no/net/cisco-hdlc.txt
*/
static int proto_chdlc = -1;
static int hf_chdlc_addr = -1;
static int hf_chdlc_proto = -1;
static gint ett_chdlc = -1;
static int proto_slarp = -1;
static int hf_slarp_ptype = -1;
static int hf_slarp_address = -1;
static int hf_slarp_mysequence = -1;
static int hf_slarp_yoursequence = -1;
static gint ett_slarp = -1;
static dissector_handle_t data_handle;
/*
* Protocol types for the Cisco HDLC format.
*
* As per the above, according to RFC 1547, these are "standard 16 bit
* Ethernet protocol type code[s]", but 0x8035 is Reverse ARP, and
* that is (at least according to the Linux ISDN code) not the
* same as Cisco SLARP.
*
* In addition, 0x2000 is apparently the Cisco Discovery Protocol, but
* on Ethernet those are encapsulated inside SNAP with an OUI of
* OUI_CISCO, not OUI_ENCAP_ETHER.
*
* Perhaps we should set up a protocol table for those protocols
* that differ between Ethernet and Cisco HDLC, and have the PPP
* code first try that table and, if it finds nothing in that
* table, call "ethertype()". (Unfortunately, that means that -
* assuming we had a Cisco SLARP dissector - said dissector were
* disabled, SLARP packets would be dissected as Reverse ARP
* packets, not as data.)
*/
#define CISCO_SLARP 0x8035 /* Cisco SLARP protocol */
static dissector_table_t subdissector_table;
static const value_string chdlc_address_vals[] = {
{CHDLC_ADDR_UNICAST, "Unicast"},
{CHDLC_ADDR_MULTICAST, "Multicast"},
{0, NULL}
};
const value_string chdlc_vals[] = {
{0x2000, "Cisco Discovery Protocol"},
{ETHERTYPE_IP, "IP"},
{CISCO_SLARP, "SLARP"},
{ETHERTYPE_DEC_LB, "DEC LanBridge"},
{CHDLCTYPE_BPDU, "Spanning Tree BPDU"},
{ETHERTYPE_ATALK, "Appletalk"},
{ETHERTYPE_AARP, "AARP"},
{ETHERTYPE_IPX, "Netware IPX/SPX"},
{ETHERTYPE_ETHBRIDGE, "Transparent Ethernet bridging" },
{CHDLCTYPE_OSI, "OSI" },
{ETHERTYPE_MPLS, "MPLS unicast"},
{ETHERTYPE_MPLS_MULTI, "MPLS multicast"},
{0, NULL}
};
void
capture_chdlc( const guchar *pd, int offset, int len, packet_counts *ld ) {
if (!BYTES_ARE_IN_FRAME(offset, len, 4)) {
ld->other++;
return;
}
switch (pntohs(&pd[offset + 2])) {
case ETHERTYPE_IP:
capture_ip(pd, offset + 4, len, ld);
break;
default:
ld->other++;
break;
}
}
void
chdlctype(guint16 chdlctype, tvbuff_t *tvb, int offset_after_chdlctype,
packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
int chdlctype_id)
{
tvbuff_t *next_tvb;
if (tree) {
proto_tree_add_uint(fh_tree, chdlctype_id, tvb,
offset_after_chdlctype - 2, 2, chdlctype);
}
next_tvb = tvb_new_subset(tvb, offset_after_chdlctype, -1, -1);
/* do lookup with the subdissector table */
if (!dissector_try_port(subdissector_table, chdlctype, next_tvb, pinfo, tree)) {
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x", chdlctype);
call_dissector(data_handle,next_tvb, pinfo, tree);
}
}
static gint chdlc_fcs_decode = 0; /* 0 = No FCS, 1 = 16 bit FCS, 2 = 32 bit FCS */
static void
dissect_chdlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *ti;
proto_tree *fh_tree = NULL;
guint8 addr;
guint16 proto;
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CHDLC");
if (check_col(pinfo->cinfo, COL_INFO))
col_clear(pinfo->cinfo, COL_INFO);
switch (pinfo->p2p_dir) {
case P2P_DIR_SENT:
if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");
if (check_col(pinfo->cinfo, COL_RES_DL_DST))
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE");
break;
case P2P_DIR_RECV:
if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE");
if (check_col(pinfo->cinfo, COL_RES_DL_DST))
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE");
break;
default:
if (check_col(pinfo->cinfo, COL_RES_DL_SRC))
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A");
if (check_col(pinfo->cinfo, COL_RES_DL_DST))
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
break;
}
addr = tvb_get_guint8(tvb, 0);
proto = tvb_get_ntohs(tvb, 2);
if (tree) {
ti = proto_tree_add_item(tree, proto_chdlc, tvb, 0, 4, FALSE);
fh_tree = proto_item_add_subtree(ti, ett_chdlc);
proto_tree_add_uint(fh_tree, hf_chdlc_addr, tvb, 0, 1, addr);
}
decode_fcs(tvb, fh_tree, chdlc_fcs_decode, 2);
chdlctype(proto, tvb, 4, pinfo, tree, fh_tree, hf_chdlc_proto);
}
void
proto_register_chdlc(void)
{
static hf_register_info hf[] = {
{ &hf_chdlc_addr,
{ "Address", "chdlc.address", FT_UINT8, BASE_HEX,
VALS(chdlc_address_vals), 0x0, "", HFILL }},
{ &hf_chdlc_proto,
{ "Protocol", "chdlc.protocol", FT_UINT16, BASE_HEX,
VALS(chdlc_vals), 0x0, "", HFILL }},
};
static gint *ett[] = {
&ett_chdlc,
};
module_t *chdlc_module;
proto_chdlc = proto_register_protocol("Cisco HDLC", "CHDLC", "chdlc");
proto_register_field_array(proto_chdlc, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* subdissector code */
subdissector_table = register_dissector_table("chdlctype",
"Cisco HDLC frame type", FT_UINT16, BASE_HEX);
register_dissector("chdlc", dissect_chdlc, proto_chdlc);
/* Register the preferences for the chdlc protocol */
chdlc_module = prefs_register_protocol(proto_chdlc, NULL);
prefs_register_enum_preference(chdlc_module,
"fcs_type",
"CHDLC Frame Checksum Type",
"The type of CHDLC frame checksum (none, 16-bit, 32-bit)",
&chdlc_fcs_decode,
fcs_options, FALSE);
}
void
proto_reg_handoff_chdlc(void)
{
dissector_handle_t chdlc_handle;
data_handle = find_dissector("data");
chdlc_handle = find_dissector("chdlc");
dissector_add("wtap_encap", WTAP_ENCAP_CHDLC, chdlc_handle);
dissector_add("wtap_encap", WTAP_ENCAP_CHDLC_WITH_PHDR, chdlc_handle);
}
#define SLARP_REQUEST 0
#define SLARP_REPLY 1
#define SLARP_LINECHECK 2
static const value_string slarp_ptype_vals[] = {
{SLARP_REQUEST, "Request"},
{SLARP_REPLY, "Reply"},
{SLARP_LINECHECK, "Line keepalive"},
{0, NULL}
};
static void
dissect_slarp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *ti;
proto_tree *slarp_tree = NULL;
guint32 code;
guint32 address;
guint32 mysequence;
guint32 yoursequence;
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "SLARP");
if (check_col(pinfo->cinfo, COL_INFO))
col_clear(pinfo->cinfo, COL_INFO);
code = tvb_get_ntohl(tvb, 0);
if (tree) {
ti = proto_tree_add_item(tree, proto_slarp, tvb, 0, 14, FALSE);
slarp_tree = proto_item_add_subtree(ti, ett_slarp);
}
switch (code) {
case SLARP_REQUEST:
case SLARP_REPLY:
if (check_col(pinfo->cinfo, COL_INFO)) {
tvb_memcpy(tvb, (guint8 *)&address, 4, 4);
col_add_fstr(pinfo->cinfo, COL_INFO, "%s, from %s, mask %s",
match_strval(code, slarp_ptype_vals),
get_hostname(address),
ip_to_str(tvb_get_ptr(tvb, 8, 4)));
}
if (tree) {
proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
proto_tree_add_item(slarp_tree, hf_slarp_address, tvb, 4, 4, FALSE);
proto_tree_add_text(slarp_tree, tvb, 8, 4,
"Netmask: %s", ip_to_str(tvb_get_ptr(tvb, 8, 4)));
}
break;
case SLARP_LINECHECK:
mysequence = tvb_get_ntohl(tvb, 4);
yoursequence = tvb_get_ntohl(tvb, 8);
if (check_col(pinfo->cinfo, COL_INFO)) {
col_add_fstr(pinfo->cinfo, COL_INFO,
"%s, outgoing sequence %u, returned sequence %u",
match_strval(code, slarp_ptype_vals),
mysequence, yoursequence);
}
if (tree) {
proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
proto_tree_add_uint(slarp_tree, hf_slarp_mysequence, tvb, 4, 4,
mysequence);
proto_tree_add_uint(slarp_tree, hf_slarp_mysequence, tvb, 8, 4,
yoursequence);
}
break;
default:
if (check_col(pinfo->cinfo, COL_INFO))
col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown packet type 0x%08X", code);
if (tree) {
proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code);
call_dissector(data_handle, tvb_new_subset(tvb, 4, -1, -1), pinfo,
slarp_tree);
}
break;
}
}
void
proto_register_slarp(void)
{
static hf_register_info hf[] = {
{ &hf_slarp_ptype,
{ "Packet type", "slarp.ptype", FT_UINT32, BASE_DEC,
VALS(slarp_ptype_vals), 0x0, "", HFILL }},
{ &hf_slarp_address,
{ "Address", "slarp.address", FT_IPv4, BASE_NONE,
NULL, 0x0, "", HFILL }},
/* XXX - need an FT_ for netmasks, which is like FT_IPV4 but doesn't
get translated to a host name. */
{ &hf_slarp_mysequence,
{ "Outgoing sequence number", "slarp.mysequence", FT_UINT32, BASE_DEC,
NULL, 0x0, "", HFILL }},
{ &hf_slarp_yoursequence,
{ "Returned sequence number", "slarp.yoursequence", FT_UINT32, BASE_DEC,
NULL, 0x0, "", HFILL }},
};
static gint *ett[] = {
&ett_chdlc,
&ett_slarp,
};
proto_slarp = proto_register_protocol("Cisco SLARP", "SLARP", "slarp");
proto_register_field_array(proto_slarp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_slarp(void)
{
dissector_handle_t slarp_handle;
slarp_handle = create_dissector_handle(dissect_slarp, proto_slarp);
dissector_add("chdlctype", CISCO_SLARP, slarp_handle);
}
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