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/*
* Copyright (c) 1998-2007 The TCPDUMP project
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code
* distributions retain the above copyright notice and this paragraph
* in its entirety, and (2) distributions including binary code include
* the above copyright notice and this paragraph in its entirety in
* the documentation or other materials provided with the distribution.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND
* WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
* LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE.
*
* Original code by Carles Kishimoto <carles.kishimoto@gmail.com>
*/
/* \summary: Cisco UniDirectional Link Detection (UDLD) protocol printer */
/* specification: RFC 5171 */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "netdissect-stdinc.h"
#define ND_LONGJMP_FROM_TCHECK
#include "netdissect.h"
#include "extract.h"
#define UDLD_HEADER_LEN 4
#define UDLD_TLV_HEADER_LEN 4
#define UDLD_DEVICE_ID_TLV 0x0001
#define UDLD_PORT_ID_TLV 0x0002
#define UDLD_ECHO_TLV 0x0003
#define UDLD_MESSAGE_INTERVAL_TLV 0x0004
#define UDLD_TIMEOUT_INTERVAL_TLV 0x0005
#define UDLD_DEVICE_NAME_TLV 0x0006
#define UDLD_SEQ_NUMBER_TLV 0x0007
static const struct tok udld_tlv_values[] = {
{ UDLD_DEVICE_ID_TLV, "Device-ID TLV"},
{ UDLD_PORT_ID_TLV, "Port-ID TLV"},
{ UDLD_ECHO_TLV, "Echo TLV"},
{ UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"},
{ UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"},
{ UDLD_DEVICE_NAME_TLV, "Device Name TLV"},
{ UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"},
{ 0, NULL}
};
static const struct tok udld_code_values[] = {
{ 0x00, "Reserved"},
{ 0x01, "Probe message"},
{ 0x02, "Echo message"},
{ 0x03, "Flush message"},
{ 0, NULL}
};
static const struct tok udld_flags_bitmap_str[] = {
{ 1U << 0, "RT" },
{ 1U << 1, "RSY" },
{ 1U << 2, "MBZ-2" },
{ 1U << 3, "MBZ-3" },
{ 1U << 4, "MBZ-4" },
{ 1U << 5, "MBZ-5" },
{ 1U << 6, "MBZ-6" },
{ 1U << 7, "MBZ-7" },
{ 0, NULL}
};
/*
* UDLD's Protocol Data Unit format:
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Ver | Opcode | Flags | Checksum |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | List of TLVs (variable length list) |
* | ... |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* TLV format:
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | TYPE | LENGTH |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | VALUE |
* | ... |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* LENGTH: Length in bytes of the Type, Length, and Value fields.
*/
#define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
#define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f)
void
udld_print(netdissect_options *ndo,
const u_char *tptr, u_int length)
{
uint8_t ver, code, flags;
ndo->ndo_protocol = "udld";
if (length < UDLD_HEADER_LEN)
goto invalid;
ver = UDLD_EXTRACT_VERSION(GET_U_1(tptr));
code = UDLD_EXTRACT_OPCODE(GET_U_1(tptr));
tptr += 1;
length -= 1;
flags = GET_U_1(tptr);
tptr += 1;
length -= 1;
ND_PRINT("UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u",
ver,
tok2str(udld_code_values, "Reserved", code),
code,
bittok2str(udld_flags_bitmap_str, "none", flags),
flags,
length + 2);
/*
* In non-verbose mode, just print version and opcode type
*/
if (ndo->ndo_vflag < 1) {
goto tcheck_remainder;
}
ND_PRINT("\n\tChecksum 0x%04x (unverified)", GET_BE_U_2(tptr));
tptr += 2;
length -= 2;
while (length) {
uint16_t type, len;
if (length < UDLD_TLV_HEADER_LEN)
goto invalid;
type = GET_BE_U_2(tptr);
tptr += 2;
length -= 2;
len = GET_BE_U_2(tptr);
tptr += 2;
length -= 2;
ND_PRINT("\n\t%s (0x%04x) TLV, length %u",
tok2str(udld_tlv_values, "Unknown", type),
type, len);
/* infinite loop check */
if (len <= UDLD_TLV_HEADER_LEN)
goto invalid;
len -= UDLD_TLV_HEADER_LEN;
if (length < len)
goto invalid;
switch (type) {
case UDLD_DEVICE_ID_TLV:
case UDLD_PORT_ID_TLV:
case UDLD_DEVICE_NAME_TLV:
ND_PRINT(", ");
nd_printjnp(ndo, tptr, len);
break;
case UDLD_ECHO_TLV:
ND_PRINT(", ");
(void)nd_printn(ndo, tptr, len, NULL);
break;
case UDLD_MESSAGE_INTERVAL_TLV:
case UDLD_TIMEOUT_INTERVAL_TLV:
if (len != 1)
goto invalid;
ND_PRINT(", %us", (GET_U_1(tptr)));
break;
case UDLD_SEQ_NUMBER_TLV:
if (len != 4)
goto invalid;
ND_PRINT(", %u", GET_BE_U_4(tptr));
break;
default:
ND_TCHECK_LEN(tptr, len);
break;
}
tptr += len;
length -= len;
}
return;
invalid:
nd_print_invalid(ndo);
tcheck_remainder:
ND_TCHECK_LEN(tptr, length);
}
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