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 <sys/cdefs.h>
21 #ifndef lint
22 __RCSID("$NetBSD: print-dtp.c,v 1.5 2024/09/02 16:15:31 christos Exp $");
23 #endif
24
25 #include <config.h>
26
27 #include "netdissect-stdinc.h"
28
29 #define ND_LONGJMP_FROM_TCHECK
30 #include "netdissect.h"
31 #include "addrtoname.h"
32 #include "extract.h"
33
34
35 #define DTP_HEADER_LEN 1
36 #define DTP_DOMAIN_TLV 0x0001
37 #define DTP_STATUS_TLV 0x0002
38 #define DTP_DTP_TYPE_TLV 0x0003
39 #define DTP_NEIGHBOR_TLV 0x0004
40
41 static const struct tok dtp_tlv_values[] = {
42 { DTP_DOMAIN_TLV, "Domain" },
43 { DTP_STATUS_TLV, "Status" },
44 { DTP_DTP_TYPE_TLV, "DTP type" },
45 { DTP_NEIGHBOR_TLV, "Neighbor" },
46 { 0, NULL}
47 };
48
49 void
dtp_print(netdissect_options * ndo,const u_char * tptr,u_int length)50 dtp_print(netdissect_options *ndo, const u_char *tptr, u_int length)
51 {
52 ndo->ndo_protocol = "dtp";
53 if (length < DTP_HEADER_LEN) {
54 ND_PRINT("[zero packet length]");
55 goto invalid;
56 }
57
58 ND_PRINT("DTPv%u, length %u",
59 GET_U_1(tptr),
60 length);
61
62 /*
63 * In non-verbose mode, just print version.
64 */
65 if (ndo->ndo_vflag < 1) {
66 return;
67 }
68
69 tptr += DTP_HEADER_LEN;
70 length -= DTP_HEADER_LEN;
71
72 while (length) {
73 uint16_t type, len;
74
75 if (length < 4) {
76 ND_PRINT("[%u bytes remaining]", length);
77 goto invalid;
78 }
79 type = GET_BE_U_2(tptr);
80 len = GET_BE_U_2(tptr + 2);
81 /* XXX: should not be but sometimes it is, see the test captures */
82 if (type == 0)
83 return;
84 ND_PRINT("\n\t%s (0x%04x) TLV, length %u",
85 tok2str(dtp_tlv_values, "Unknown", type),
86 type, len);
87
88 /* infinite loop check */
89 if (len < 4 || len > length) {
90 ND_PRINT("[TLV length %u]", len);
91 goto invalid;
92 }
93
94 switch (type) {
95 case DTP_DOMAIN_TLV:
96 ND_PRINT(", ");
97 nd_printjnp(ndo, tptr+4, len-4);
98 break;
99
100 case DTP_STATUS_TLV:
101 case DTP_DTP_TYPE_TLV:
102 if (len != 5)
103 goto invalid;
104 ND_PRINT(", 0x%x", GET_U_1(tptr + 4));
105 break;
106
107 case DTP_NEIGHBOR_TLV:
108 if (len != 10)
109 goto invalid;
110 ND_PRINT(", %s", GET_ETHERADDR_STRING(tptr+4));
111 break;
112
113 default:
114 ND_TCHECK_LEN(tptr, len);
115 break;
116 }
117 tptr += len;
118 length -= len;
119 }
120 return;
121
122 invalid:
123 nd_print_invalid(ndo);
124 ND_TCHECK_LEN(tptr, length);
125 }
126