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