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wireshark/packet-cdp.c

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/* packet-cdp.c
* Routines for the disassembly of the "Cisco Discovery Protocol"
* (c) Copyright Hannes R. Boehm <hannes@boehm.org>
*
* $Id: packet-cdp.c,v 1.38 2001/06/20 05:18:36 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.
*/
#include "config.h"
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#include "packet.h"
#include "strutil.h"
#include "nlpid.h"
/*
* See
*
* http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm
*
* for some information on CDP.
*/
/* Offsets in TLV structure. */
#define TLV_TYPE 0
#define TLV_LENGTH 2
static int proto_cdp = -1;
static int hf_cdp_version = -1;
static int hf_cdp_checksum = -1;
static int hf_cdp_ttl = -1;
static int hf_cdp_tlvtype = -1;
static int hf_cdp_tlvlength = -1;
static gint ett_cdp = -1;
static gint ett_cdp_tlv = -1;
static gint ett_cdp_address = -1;
static gint ett_cdp_capabilities = -1;
static int
dissect_address_tlv(tvbuff_t *tvb, int offset, int length, proto_tree *tree);
static void
dissect_capabilities(tvbuff_t *tvb, int offset, int length, proto_tree *tree);
static void
add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
gint len, const gchar *prefix);
#define TYPE_DEVICE_ID 0x0001
#define TYPE_ADDRESS 0x0002
#define TYPE_PORT_ID 0x0003
#define TYPE_CAPABILITIES 0x0004
#define TYPE_IOS_VERSION 0x0005
#define TYPE_PLATFORM 0x0006
#define TYPE_IP_PREFIX 0x0007
#define TYPE_VTP_MGMT_DOMAIN 0x0009 /* Guessed, from tcpdump */
#define TYPE_NATIVE_VLAN 0x000a /* Guessed, from tcpdump */
#define TYPE_DUPLEX 0x000b /* Guessed, from tcpdump */
static const value_string type_vals[] = {
{ TYPE_DEVICE_ID, "Device ID" },
{ TYPE_ADDRESS, "Addresses" },
{ TYPE_PORT_ID, "Port ID" },
{ TYPE_CAPABILITIES, "Capabilities" },
{ TYPE_IOS_VERSION, "Software version" },
{ TYPE_PLATFORM, "Platform" },
{ TYPE_IP_PREFIX, "IP Prefix (used for ODR)" },
{ TYPE_VTP_MGMT_DOMAIN, "VTP Management Domain" },
{ TYPE_NATIVE_VLAN, "Native VLAN" },
{ TYPE_DUPLEX, "Duplex" },
{ 0, NULL },
};
static void
dissect_cdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *ti;
proto_tree *cdp_tree = NULL;
int offset = 0;
guint16 type;
guint16 length;
proto_item *tlvi;
proto_tree *tlv_tree;
int real_length;
guint32 naddresses;
int addr_length;
if (check_col(pinfo->fd, COL_PROTOCOL))
col_set_str(pinfo->fd, COL_PROTOCOL, "CDP");
if (check_col(pinfo->fd, COL_INFO))
col_set_str(pinfo->fd, COL_INFO, "Cisco Discovery Protocol");
if (tree){
ti = proto_tree_add_item(tree, proto_cdp, tvb, offset,
tvb_length_remaining(tvb, offset), FALSE);
cdp_tree = proto_item_add_subtree(ti, ett_cdp);
/* CDP header */
proto_tree_add_item(cdp_tree, hf_cdp_version, tvb, offset, 1, FALSE);
offset += 1;
proto_tree_add_uint_format(cdp_tree, hf_cdp_ttl, tvb, offset, 1,
tvb_get_guint8(tvb, offset),
"TTL: %u seconds",
tvb_get_guint8(tvb, offset));
offset += 1;
proto_tree_add_item(cdp_tree, hf_cdp_checksum, tvb, offset, 2, FALSE);
offset += 2;
while (tvb_reported_length_remaining(tvb, offset) != 0) {
type = tvb_get_ntohs(tvb, offset + TLV_TYPE);
length = tvb_get_ntohs(tvb, offset + TLV_LENGTH);
if (length < 4) {
tlvi = proto_tree_add_text(cdp_tree, tvb, offset, 4,
"TLV with invalid length %u (< 4)",
length);
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
offset += 4;
break;
}
switch (type) {
case TYPE_DEVICE_ID:
/* Device ID */
tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
length, "Device ID: %.*s",
length - 4,
tvb_get_ptr(tvb, offset + 4, length - 4));
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
proto_tree_add_text(tlv_tree, tvb, offset + 4,
length - 4, "Device ID: %.*s",
length - 4,
tvb_get_ptr(tvb, offset + 4, length - 4));
offset += length;
break;
case TYPE_ADDRESS:
/* Addresses */
tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
length, "Addresses");
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
offset += 4;
length -= 4;
naddresses = tvb_get_ntohl(tvb, offset);
proto_tree_add_text(tlv_tree, tvb, offset, 4,
"Number of addresses: %u", naddresses);
offset += 4;
length -= 4;
while (naddresses != 0) {
addr_length = dissect_address_tlv(tvb, offset, length,
tlv_tree);
if (addr_length < 0)
break;
offset += addr_length;
length -= addr_length;
naddresses--;
}
offset += length;
break;
case TYPE_PORT_ID:
real_length = length;
if (tvb_get_guint8(tvb, offset + real_length) != 0x00) {
/* The length in the TLV doesn't appear to be the
length of the TLV, as the byte just past it
isn't the first byte of a 2-byte big-endian
small integer; make the length of the TLV the length
in the TLV, plus 4 bytes for the TLV type and length,
minus 1 because that's what makes one capture work. */
real_length = length + 3;
}
tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
real_length, "Port ID: %.*s",
real_length - 4,
tvb_get_ptr(tvb, offset + 4, real_length - 4));
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
proto_tree_add_text(tlv_tree, tvb, offset + 4,
real_length - 4,
"Sent through Interface: %.*s",
real_length - 4,
tvb_get_ptr(tvb, offset + 4, real_length - 4));
offset += real_length;
break;
case TYPE_CAPABILITIES:
tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
length, "Capabilities");
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
offset += 4;
length -= 4;
dissect_capabilities(tvb, offset, length, tlv_tree);
offset += length;
break;
case TYPE_IOS_VERSION:
tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
length, "Software Version");
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
add_multi_line_string_to_tree(tlv_tree, tvb, offset + 4,
length - 4, "Software Version: ");
offset += length;
break;
case TYPE_PLATFORM:
/* ??? platform */
tlvi = proto_tree_add_text(cdp_tree, tvb,
offset, length, "Platform: %.*s",
length - 4,
tvb_get_ptr(tvb, offset + 4, length - 4));
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
proto_tree_add_text(tlv_tree, tvb, offset + 4,
length - 4, "Platform: %.*s",
length - 4,
tvb_get_ptr(tvb, offset + 4, length - 4));
offset += length;
break;
case TYPE_IP_PREFIX:
tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
length, "IP Prefixes: %d",length/5);
/* the actual number of prefixes is (length-4)/5
but if the variable is not a "float" but "integer"
then length/5=(length-4)/5 :) */
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
offset += 4;
length -= 4;
while (length > 0) {
proto_tree_add_text(tlv_tree, tvb, offset, 5,
"IP Prefix = %s/%u",
ip_to_str(tvb_get_ptr(tvb, offset, 4)),
tvb_get_guint8(tvb,offset+4));
offset += 5;
length -= 5;
}
break;
case TYPE_VTP_MGMT_DOMAIN:
tlvi = proto_tree_add_text(cdp_tree, tvb,
offset, length, "VTP Management Domain: %.*s",
length - 4,
tvb_get_ptr(tvb, offset + 4, length - 4));
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
proto_tree_add_text(tlv_tree, tvb, offset + 4,
length - 4, "VTP Management Domain: %.*s",
length - 4,
tvb_get_ptr(tvb, offset + 4, length - 4));
offset += length;
break;
case TYPE_NATIVE_VLAN:
tlvi = proto_tree_add_text(cdp_tree, tvb,
offset, length, "Native VLAN: %u",
tvb_get_ntohs(tvb, offset + 4));
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
proto_tree_add_text(tlv_tree, tvb, offset + 4,
length - 4, "Native VLAN: %u",
tvb_get_ntohs(tvb, offset + 4));
offset += length;
break;
case TYPE_DUPLEX:
tlvi = proto_tree_add_text(cdp_tree, tvb,
offset, length, "Duplex: %s",
tvb_get_guint8(tvb, offset + 4) ?
"Full" : "Half" );
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
proto_tree_add_text(tlv_tree, tvb, offset + 4,
length - 4, "Duplex: %s",
tvb_get_guint8(tvb, offset + 4) ?
"Full" : "Half" );
offset += length;
break;
default:
tlvi = proto_tree_add_text(cdp_tree, tvb, offset,
length, "Type: %s, length: %u",
val_to_str(type, type_vals, "Unknown (0x%04x)"),
length);
tlv_tree = proto_item_add_subtree(tlvi, ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, tvb,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, tvb,
offset + TLV_LENGTH, 2, length);
if (length > 4) {
proto_tree_add_text(tlv_tree, tvb, offset + 4,
length - 4, "Data");
} else
return;
offset += length;
}
}
dissect_data(tvb, offset, pinfo, cdp_tree);
}
}
#define PROTO_TYPE_NLPID 1
#define PROTO_TYPE_IEEE_802_2 2
static const value_string proto_type_vals[] = {
{ PROTO_TYPE_NLPID, "NLPID" },
{ PROTO_TYPE_IEEE_802_2, "802.2" },
{ 0, NULL },
};
static int
dissect_address_tlv(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
{
proto_item *ti;
proto_tree *address_tree;
guint8 protocol_type;
guint8 protocol_length;
int nlpid;
char *protocol_str;
guint16 address_length;
char *address_type_str;
char *address_str;
if (length < 1)
return -1;
ti = proto_tree_add_notext(tree, tvb, offset, length);
address_tree = proto_item_add_subtree(ti, ett_cdp_address);
protocol_type = tvb_get_guint8(tvb, offset);
proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol type: %s",
val_to_str(protocol_type, proto_type_vals, "Unknown (0x%02x)"));
offset += 1;
length -= 1;
if (length < 1) {
proto_item_set_text(ti, "Truncated address");
return -1;
}
protocol_length = tvb_get_guint8(tvb, offset);
proto_tree_add_text(address_tree, tvb, offset, 1, "Protocol length: %u",
protocol_length);
offset += 1;
length -= 1;
if (length < protocol_length) {
proto_item_set_text(ti, "Truncated address");
if (length != 0) {
proto_tree_add_text(address_tree, tvb, offset, length,
"Protocol: %s (truncated)",
tvb_bytes_to_str(tvb, offset, length));
}
return -1;
}
protocol_str = NULL;
if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
nlpid = tvb_get_guint8(tvb, offset);
protocol_str = val_to_str(nlpid, nlpid_vals, "Unknown (0x%02x)");
} else
nlpid = -1;
if (protocol_str == NULL)
protocol_str = tvb_bytes_to_str(tvb, offset, protocol_length);
proto_tree_add_text(address_tree, tvb, offset, protocol_length,
"Protocol: %s", protocol_str);
offset += protocol_length;
length -= protocol_length;
if (length < 2) {
proto_item_set_text(ti, "Truncated address");
return -1;
}
address_length = tvb_get_ntohs(tvb, offset);
proto_tree_add_text(address_tree, tvb, offset, 2, "Address length: %u",
address_length);
offset += 2;
length -= 2;
if (length < address_length) {
proto_item_set_text(ti, "Truncated address");
if (length != 0) {
proto_tree_add_text(address_tree, tvb, offset, length,
"Address: %s (truncated)",
tvb_bytes_to_str(tvb, offset, length));
}
return -1;
}
/* XXX - the Cisco document seems to be saying that, for 802.2-format
protocol types, 0xAAAA03 0x000000 0x0800 is IPv6, but 0x0800 is
the Ethernet protocol type for IPv4. */
length = 2 + protocol_length + 2 + address_length;
address_type_str = NULL;
address_str = NULL;
if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
switch (nlpid) {
/* XXX - dissect NLPID_ISO8473_CLNP as OSI CLNP address? */
case NLPID_IP:
if (address_length == 4) {
/* The address is an IP address. */
address_type_str = "IP address";
address_str = ip_to_str(tvb_get_ptr(tvb, offset, 4));
}
break;
}
}
if (address_type_str == NULL)
address_type_str = "Address";
if (address_str == NULL) {
address_str = tvb_bytes_to_str(tvb, offset, address_length);
}
proto_item_set_text(ti, "%s: %s", address_type_str, address_str);
proto_tree_add_text(address_tree, tvb, offset, address_length, "%s: %s",
address_type_str, address_str);
return 2 + protocol_length + 2 + address_length;
}
static void
dissect_capabilities(tvbuff_t *tvb, int offset, int length, proto_tree *tree)
{
proto_item *ti;
proto_tree *capabilities_tree;
guint32 capabilities;
if (length < 4)
return;
capabilities = tvb_get_ntohl(tvb, offset);
ti = proto_tree_add_text(tree, tvb, offset, length, "Capabilities: 0x%08x",
capabilities);
capabilities_tree = proto_item_add_subtree(ti, ett_cdp_capabilities);
proto_tree_add_text(capabilities_tree, tvb, offset, 4,
decode_boolean_bitfield(capabilities, 0x01, 4*8,
"Performs level 3 routing",
"Doesn't perform level 3 routing"));
proto_tree_add_text(capabilities_tree, tvb, offset, 4,
decode_boolean_bitfield(capabilities, 0x02, 4*8,
"Performs level 2 transparent bridging",
"Doesn't perform level 2 transparent bridging"));
proto_tree_add_text(capabilities_tree, tvb, offset, 4,
decode_boolean_bitfield(capabilities, 0x04, 4*8,
"Performs level 2 source-route bridging",
"Doesn't perform level 2 source-route bridging"));
proto_tree_add_text(capabilities_tree, tvb, offset, 4,
decode_boolean_bitfield(capabilities, 0x08, 4*8,
"Performs level 2 switching",
"Doesn't perform level 2 switching"));
proto_tree_add_text(capabilities_tree, tvb, offset, 4,
decode_boolean_bitfield(capabilities, 0x10, 4*8,
"Sends and receives packets for network-layer protocols",
"Doesn't send or receive packets for network-layer protocols"));
proto_tree_add_text(capabilities_tree, tvb, offset, 4,
decode_boolean_bitfield(capabilities, 0x20, 4*8,
"Doesn't forward IGMP Report packets on nonrouter ports",
"Forwards IGMP Report packets on nonrouter ports"));
proto_tree_add_text(capabilities_tree, tvb, offset, 4,
decode_boolean_bitfield(capabilities, 0x40, 4*8,
"Provides level 1 functionality",
"Doesn't provide level 1 functionality"));
}
static void
add_multi_line_string_to_tree(proto_tree *tree, tvbuff_t *tvb, gint start,
gint len, const gchar *prefix)
{
int prefix_len;
int i;
char blanks[64+1];
gint next;
int line_len;
int data_len;
prefix_len = strlen(prefix);
if (prefix_len > 64)
prefix_len = 64;
for (i = 0; i < prefix_len; i++)
blanks[i] = ' ';
blanks[i] = '\0';
while (len > 0) {
line_len = tvb_find_line_end(tvb, start, len, &next);
data_len = next - start;
proto_tree_add_text(tree, tvb, start, data_len, "%s%.*s", prefix,
line_len, tvb_get_ptr(tvb, start, line_len));
start += data_len;
len -= data_len;
prefix = blanks;
}
}
void
proto_register_cdp(void)
{
static hf_register_info hf[] = {
{ &hf_cdp_version,
{ "Version", "cdp.version", FT_UINT8, BASE_DEC, NULL, 0x0,
"", HFILL }},
{ &hf_cdp_ttl,
{ "TTL", "cdp.ttl", FT_UINT16, BASE_DEC, NULL, 0x0,
"", HFILL }},
{ &hf_cdp_checksum,
{ "Checksum", "cdp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
"", HFILL }},
{ &hf_cdp_tlvtype,
{ "Type", "cdp.tlv.type", FT_UINT16, BASE_HEX, VALS(type_vals), 0x0,
"", HFILL }},
{ &hf_cdp_tlvlength,
{ "Length", "cdp.tlv.len", FT_UINT16, BASE_DEC, NULL, 0x0,
"", HFILL }},
};
static gint *ett[] = {
&ett_cdp,
&ett_cdp_tlv,
&ett_cdp_address,
&ett_cdp_capabilities,
};
proto_cdp = proto_register_protocol("Cisco Discovery Protocol",
"CDP", "cdp");
proto_register_field_array(proto_cdp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_cdp(void)
{
dissector_add("llc.cisco_pid", 0x2000, dissect_cdp, proto_cdp);
dissector_add("chdlctype", 0x2000, dissect_cdp, proto_cdp);
}
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