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 * Original code by Carles Kishimoto <carles.kishimoto@gmail.com>
16 */
17
18/* \summary: Dynamic Trunking Protocol (DTP) printer */
19
20#ifdef HAVE_CONFIG_H
21#include <config.h>
22#endif
23
24#include "netdissect-stdinc.h"
25
26#define ND_LONGJMP_FROM_TCHECK
27#include "netdissect.h"
28#include "addrtoname.h"
29#include "extract.h"
30
31
32#define DTP_HEADER_LEN			1
33#define DTP_DOMAIN_TLV			0x0001
34#define DTP_STATUS_TLV			0x0002
35#define DTP_DTP_TYPE_TLV		0x0003
36#define DTP_NEIGHBOR_TLV		0x0004
37
38static const struct tok dtp_tlv_values[] = {
39    { DTP_DOMAIN_TLV, "Domain" },
40    { DTP_STATUS_TLV, "Status" },
41    { DTP_DTP_TYPE_TLV, "DTP type" },
42    { DTP_NEIGHBOR_TLV, "Neighbor" },
43    { 0, NULL}
44};
45
46void
47dtp_print(netdissect_options *ndo, const u_char *tptr, u_int length)
48{
49    ndo->ndo_protocol = "dtp";
50    if (length < DTP_HEADER_LEN) {
51        ND_PRINT("[zero packet length]");
52        goto invalid;
53    }
54
55    ND_PRINT("DTPv%u, length %u",
56           GET_U_1(tptr),
57           length);
58
59    /*
60     * In non-verbose mode, just print version.
61     */
62    if (ndo->ndo_vflag < 1) {
63	return;
64    }
65
66    tptr += DTP_HEADER_LEN;
67    length -= DTP_HEADER_LEN;
68
69    while (length) {
70        uint16_t type, len;
71
72        if (length < 4) {
73            ND_PRINT("[%u bytes remaining]", length);
74            goto invalid;
75        }
76	type = GET_BE_U_2(tptr);
77        len  = GET_BE_U_2(tptr + 2);
78       /* XXX: should not be but sometimes it is, see the test captures */
79        if (type == 0)
80            return;
81        ND_PRINT("\n\t%s (0x%04x) TLV, length %u",
82               tok2str(dtp_tlv_values, "Unknown", type),
83               type, len);
84
85        /* infinite loop check */
86        if (len < 4 || len > length) {
87            ND_PRINT("[invalid TLV length %u]", len);
88            goto invalid;
89        }
90
91        switch (type) {
92	case DTP_DOMAIN_TLV:
93		ND_PRINT(", ");
94		nd_printjnp(ndo, tptr+4, len-4);
95		break;
96
97	case DTP_STATUS_TLV:
98	case DTP_DTP_TYPE_TLV:
99                if (len != 5)
100                    goto invalid;
101                ND_PRINT(", 0x%x", GET_U_1(tptr + 4));
102                break;
103
104	case DTP_NEIGHBOR_TLV:
105                if (len != 10)
106                    goto invalid;
107                ND_PRINT(", %s", GET_ETHERADDR_STRING(tptr+4));
108                break;
109
110        default:
111            ND_TCHECK_LEN(tptr, len);
112            break;
113        }
114        tptr += len;
115        length -= len;
116    }
117    return;
118
119 invalid:
120    nd_print_invalid(ndo);
121    ND_TCHECK_LEN(tptr, length);
122}
123