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1 office 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  
40 static 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  
51 static 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  
59 static 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  
81 void
82 udld_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 */