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wireshark/packet-cdp.c
Guy Harris aa4cd01b9b Get rid of "proto_tree_add_notext()" - if you create a subtree using it, 
but, before you set the text, you throw an exception while putting stuff
under the subtree, you end up with an absolutely blank protocol tree
item, which is really gross.  Instead of calling
"proto_tree_add_notext()", call "proto_tree_add_text()" with at least a
minimal label - yes, it does mean you do some work that will probably be
unnecessary, but, absent a scheme to arrange to do that work if it *is*
necessary (e.g., catching exceptions), the alternative is an ugly
protocol tree display.

svn path=/trunk/; revision=3879
2001-08-28 08:28:19 +00:00

584 lines
19 KiB
C
Raw Blame History

/* 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 1.39 2001/08/28 08:28:14 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.
*/
#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_text(tree, tvb, offset, length, "Truncated address");
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)
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) {
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)
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) {
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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