1/*
2 * Copyright (c) 1998-2007 The TCPDUMP project
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that: (1) source code
6 * distributions retain the above copyright notice and this paragraph
7 * in its entirety, and (2) distributions including binary code include
8 * the above copyright notice and this paragraph in its entirety in
9 * the documentation or other materials provided with the distribution.
10 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
11 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
12 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
13 * FOR A PARTICULAR PURPOSE.
14 *
15 * UNIDIRECTIONAL LINK DETECTION (UDLD) as per
16 * http://www.ietf.org/internet-drafts/draft-foschiano-udld-02.txt
17 *
18 * Original code by Carles Kishimoto <carles.kishimoto@gmail.com>
19 */
20
21#define NETDISSECT_REWORKED
22#ifdef HAVE_CONFIG_H
23#include "config.h"
24#endif
25
26#include <tcpdump-stdinc.h>
27
28#include "interface.h"
29#include "extract.h"
30
31#define UDLD_HEADER_LEN			4
32#define UDLD_DEVICE_ID_TLV		0x0001
33#define UDLD_PORT_ID_TLV		0x0002
34#define UDLD_ECHO_TLV			0x0003
35#define UDLD_MESSAGE_INTERVAL_TLV	0x0004
36#define UDLD_TIMEOUT_INTERVAL_TLV	0x0005
37#define UDLD_DEVICE_NAME_TLV		0x0006
38#define UDLD_SEQ_NUMBER_TLV		0x0007
39
40static const struct tok udld_tlv_values[] = {
41    { UDLD_DEVICE_ID_TLV, "Device-ID TLV"},
42    { UDLD_PORT_ID_TLV, "Port-ID TLV"},
43    { UDLD_ECHO_TLV, "Echo TLV"},
44    { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"},
45    { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"},
46    { UDLD_DEVICE_NAME_TLV, "Device Name TLV"},
47    { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"},
48    { 0, NULL}
49};
50
51static const struct tok udld_code_values[] = {
52    { 0x00, "Reserved"},
53    { 0x01, "Probe message"},
54    { 0x02, "Echo message"},
55    { 0x03, "Flush message"},
56    { 0, NULL}
57};
58
59static const struct tok udld_flags_values[] = {
60    { 0x00, "RT"},
61    { 0x01, "RSY"},
62    { 0, NULL}
63};
64
65/*
66 *
67 * 0                   1                   2                   3
68 * 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
69 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
70 * | Ver | Opcode  |     Flags     |           Checksum            |
71 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
72 * |               List of TLVs (variable length list)             |
73 * |                              ...                              |
74 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
75 *
76 */
77
78#define	UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
79#define	UDLD_EXTRACT_OPCODE(x) ((x)&0x1f)
80
81void
82udld_print (netdissect_options *ndo, const u_char *pptr, u_int length)
83{
84    int code, type, len;
85    const u_char *tptr;
86
87    if (length < UDLD_HEADER_LEN)
88        goto trunc;
89
90    tptr = pptr;
91
92    ND_TCHECK2(*tptr, UDLD_HEADER_LEN);
93
94    code = UDLD_EXTRACT_OPCODE(*tptr);
95
96    ND_PRINT((ndo, "UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u",
97           UDLD_EXTRACT_VERSION(*tptr),
98           tok2str(udld_code_values, "Reserved", code),
99           code,
100           bittok2str(udld_flags_values, "none", *(tptr+1)),
101           *(tptr+1),
102           length));
103
104    /*
105     * In non-verbose mode, just print version and opcode type
106     */
107    if (ndo->ndo_vflag < 1) {
108	return;
109    }
110
111    ND_PRINT((ndo, "\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2)));
112
113    tptr += UDLD_HEADER_LEN;
114
115    while (tptr < (pptr+length)) {
116
117        ND_TCHECK2(*tptr, 4);
118
119	type = EXTRACT_16BITS(tptr);
120        len  = EXTRACT_16BITS(tptr+2);
121        len -= 4;
122        tptr += 4;
123
124        /* infinite loop check */
125        if (type == 0 || len == 0) {
126            return;
127        }
128
129        ND_PRINT((ndo, "\n\t%s (0x%04x) TLV, length %u",
130               tok2str(udld_tlv_values, "Unknown", type),
131               type, len));
132
133        switch (type) {
134        case UDLD_DEVICE_ID_TLV:
135        case UDLD_PORT_ID_TLV:
136        case UDLD_ECHO_TLV:
137        case UDLD_DEVICE_NAME_TLV:
138            ND_PRINT((ndo, ", %s", tptr));
139            break;
140
141        case UDLD_MESSAGE_INTERVAL_TLV:
142        case UDLD_TIMEOUT_INTERVAL_TLV:
143            ND_PRINT((ndo, ", %us", (*tptr)));
144            break;
145
146        case UDLD_SEQ_NUMBER_TLV:
147            ND_PRINT((ndo, ", %u", EXTRACT_32BITS(tptr)));
148            break;
149
150        default:
151            break;
152        }
153        tptr += len;
154    }
155
156    return;
157
158 trunc:
159    ND_PRINT((ndo, "[|udld]"));
160}
161
162/*
163 * Local Variables:
164 * c-style: whitesmith
165 * c-basic-offset: 4
166 * End:
167 */
168