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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 1.25 2000/08/13 14:08:04 deniel 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 "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_flags = -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(const u_char *pd, int offset, int length, proto_tree *tree);
static void
dissect_capabilities(const u_char *pd, int offset, int length, proto_tree *tree);
static void
add_multi_line_string_to_tree(proto_tree *tree, gint start, gint len,
const gchar *prefix, const gchar *string);
#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
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" },
{ 0, NULL },
};
void
dissect_cdp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
{
proto_item *ti;
proto_tree *cdp_tree = NULL;
guint16 type;
guint16 length;
char *type_str;
char *stringmem;
proto_item *tlvi;
proto_tree *tlv_tree;
int real_length;
guint32 naddresses;
int addr_length;
OLD_CHECK_DISPLAY_AS_DATA(proto_cdp, pd, offset, fd, tree);
if (check_col(fd, COL_PROTOCOL))
col_add_str(fd, COL_PROTOCOL, "CDP");
if (check_col(fd, COL_INFO))
col_add_str(fd, COL_INFO, "Cisco Discovery Protocol");
if(tree){
ti = proto_tree_add_item(tree, proto_cdp, NullTVB, offset, END_OF_FRAME, FALSE);
cdp_tree = proto_item_add_subtree(ti, ett_cdp);
/* CDP header */
proto_tree_add_uint(cdp_tree, hf_cdp_version, NullTVB, offset, 1, pd[offset]);
offset += 1;
proto_tree_add_uint_format(cdp_tree, hf_cdp_ttl, NullTVB, offset, 1,
pntohs(&pd[offset]),
"TTL: %u seconds", pd[offset]);
offset += 1;
proto_tree_add_uint_format(cdp_tree, hf_cdp_flags, NullTVB, offset, 2,
pd[offset],
"Checksum: 0x%04x", pntohs(&pd[offset]));
offset += 2;
while( IS_DATA_IN_FRAME(offset) ){
type = pntohs(&pd[offset + TLV_TYPE]);
length = pntohs(&pd[offset + TLV_LENGTH]);
type_str = val_to_str(type, type_vals,
"Unknown (0x%04x)");
switch( type ){
case TYPE_DEVICE_ID:
/* Device ID */
tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
length, "Device ID: %s",
&pd[offset+4]);
tlv_tree = proto_item_add_subtree(tlvi,
ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
offset + TLV_LENGTH, 2, length);
proto_tree_add_text(tlv_tree, NullTVB, offset + 4,
length - 4, "Device ID: %s",
&pd[offset+4]);
offset+=length;
break;
case TYPE_ADDRESS:
/* Addresses */
tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
length, "Addresses");
tlv_tree = proto_item_add_subtree(tlvi,
ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
offset + TLV_LENGTH, 2, length);
offset += 4;
length -= 4;
naddresses = pntohl(&pd[offset]);
proto_tree_add_text(tlv_tree, NullTVB, offset, 4,
"Number of addresses: %u", naddresses);
offset += 4;
length -= 4;
while (naddresses != 0) {
addr_length = dissect_address_tlv(pd,
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 (pd[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, NullTVB, offset,
real_length, "Port ID: %s",
&pd[offset+4]);
tlv_tree = proto_item_add_subtree(tlvi,
ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
offset + TLV_LENGTH, 2, length);
proto_tree_add_text(tlv_tree, NullTVB, offset + 4,
real_length - 4,
"Sent through Interface: %s",
&pd[offset+4]);
offset += real_length;
break;
case TYPE_CAPABILITIES:
tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
length, "Capabilities");
tlv_tree = proto_item_add_subtree(tlvi,
ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
offset + TLV_LENGTH, 2, length);
offset += 4;
length -= 4;
dissect_capabilities(pd, offset, length,
tlv_tree);
offset += length;
break;
case TYPE_IOS_VERSION:
tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
length, "Software Version");
tlv_tree = proto_item_add_subtree(tlvi,
ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
offset + TLV_LENGTH, 2, length);
add_multi_line_string_to_tree(tlv_tree,
offset + 4, length - 4, "Software Version: ",
&pd[offset+4] );
offset += length;
break;
case TYPE_PLATFORM:
/* ??? platform */
stringmem = malloc(length);
memset(stringmem, '\0', length);
memcpy(stringmem, &pd[offset+4], length - 4 );
tlvi = proto_tree_add_text(cdp_tree, NullTVB,
offset, length, "Platform: %s",
stringmem);
tlv_tree = proto_item_add_subtree(tlvi,
ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
offset + TLV_LENGTH, 2, length);
proto_tree_add_text(tlv_tree, NullTVB, offset + 4,
length - 4, "Platform: %s", stringmem);
free(stringmem);
offset+=length;
break;
default:
tlvi = proto_tree_add_text(cdp_tree, NullTVB, offset,
length, "Type: %s, length: %u",
type_str, length);
tlv_tree = proto_item_add_subtree(tlvi,
ett_cdp_tlv);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvtype, NullTVB,
offset + TLV_TYPE, 2, type);
proto_tree_add_uint(tlv_tree, hf_cdp_tlvlength, NullTVB,
offset + TLV_LENGTH, 2, length);
if (length > 4) {
proto_tree_add_text(tlv_tree, NullTVB,
offset + 4, length - 4, "Data");
} else
return;
offset+=length;
}
}
old_dissect_data(pd, offset, fd, 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(const u_char *pd, 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, NullTVB, offset, length);
address_tree = proto_item_add_subtree(ti, ett_cdp_address);
protocol_type = pd[offset];
proto_tree_add_text(address_tree, NullTVB, 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 = pd[offset];
proto_tree_add_text(address_tree, NullTVB, 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, NullTVB, offset, length,
"Protocol: %s (truncated)", bytes_to_str(&pd[offset], length));
}
return -1;
}
protocol_str = NULL;
if (protocol_type == PROTO_TYPE_NLPID && protocol_length == 1) {
nlpid = pd[offset];
protocol_str = val_to_str(nlpid, nlpid_vals, "Unknown (0x%02x)");
} else
nlpid = -1;
if (protocol_str == NULL)
protocol_str = bytes_to_str(&pd[offset], protocol_length);
proto_tree_add_text(address_tree, NullTVB, 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 = pntohs(&pd[offset]);
proto_tree_add_text(address_tree, NullTVB, 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, NullTVB, offset, length,
"Address: %s (truncated)", bytes_to_str(&pd[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(&pd[offset]);
}
break;
}
}
if (address_type_str == NULL)
address_type_str = "Address";
if (address_str == NULL) {
address_str = bytes_to_str(&pd[offset], address_length);
}
proto_item_set_text(ti, "%s: %s", address_type_str, address_str);
proto_tree_add_text(address_tree, NullTVB, offset, address_length, "%s: %s",
address_type_str, address_str);
return 2 + protocol_length + 2 + address_length;
}
static void
dissect_capabilities(const u_char *pd, int offset, int length, proto_tree *tree)
{
proto_item *ti;
proto_tree *capabilities_tree;
guint32 capabilities;
if (length < 4)
return;
capabilities = pntohl(&pd[offset]);
ti = proto_tree_add_text(tree, NullTVB, offset, length, "Capabilities: 0x%08x",
capabilities);
capabilities_tree = proto_item_add_subtree(ti, ett_cdp_capabilities);
proto_tree_add_text(capabilities_tree, NullTVB, 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, NullTVB, 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, NullTVB, 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, NullTVB, 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, NullTVB, 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, NullTVB, 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, NullTVB, 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, gint start, gint len,
const gchar *prefix, const gchar *string)
{
int prefix_len;
int i;
char blanks[64+1];
const gchar *p, *q;
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';
p = string;
for (;;) {
q = strchr(p, '\n');
if (q != NULL) {
line_len = q - p;
data_len = line_len + 1;
} else {
line_len = strlen(p);
data_len = line_len;
}
proto_tree_add_text(tree, NullTVB, start, data_len, "%s%.*s", prefix,
line_len, p);
if (q == NULL)
break;
p += data_len;
start += 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,
"" }},
{ &hf_cdp_flags,
{ "Flags", "cdp.flags", FT_UINT8, BASE_HEX, NULL, 0x0,
"" }},
{ &hf_cdp_ttl,
{ "TTL", "cdp.ttl", FT_UINT16, BASE_DEC, NULL, 0x0,
"" }},
{ &hf_cdp_tlvtype,
{ "Type", "cdp.tlv.type", FT_UINT16, BASE_HEX, VALS(type_vals), 0x0,
"" }},
{ &hf_cdp_tlvlength,
{ "Length", "cdp.tlv.len", FT_UINT16, BASE_DEC, NULL, 0x0,
"" }},
};
static gint *ett[] = {
&ett_cdp,
&ett_cdp_tlv,
&ett_cdp_address,
&ett_cdp_capabilities,
};
proto_cdp = proto_register_protocol("Cisco Discovery Protocol", "cdp");
proto_register_field_array(proto_cdp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
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