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 #ifdef HAVE_CONFIG_H
22 #include "config.h"
23 #endif
24
25 #include <tcpdump-stdinc.h>
26
27 #include <stdio.h>
28 #include <string.h>
29
30 #include "interface.h"
31 #include "addrtoname.h"
32 #include "extract.h"
33 #include "nlpid.h"
34
35 #define UDLD_HEADER_LEN 4
36 #define UDLD_DEVICE_ID_TLV 0x0001
37 #define UDLD_PORT_ID_TLV 0x0002
38 #define UDLD_ECHO_TLV 0x0003
39 #define UDLD_MESSAGE_INTERVAL_TLV 0x0004
40 #define UDLD_TIMEOUT_INTERVAL_TLV 0x0005
41 #define UDLD_DEVICE_NAME_TLV 0x0006
42 #define UDLD_SEQ_NUMBER_TLV 0x0007
43
44 static const struct tok udld_tlv_values[] = {
45 { UDLD_DEVICE_ID_TLV, "Device-ID TLV"},
46 { UDLD_PORT_ID_TLV, "Port-ID TLV"},
47 { UDLD_ECHO_TLV, "Echo TLV"},
48 { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"},
49 { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"},
50 { UDLD_DEVICE_NAME_TLV, "Device Name TLV"},
51 { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"},
52 { 0, NULL}
53 };
54
55 static const struct tok udld_code_values[] = {
56 { 0x00, "Reserved"},
57 { 0x01, "Probe message"},
58 { 0x02, "Echo message"},
59 { 0x03, "Flush message"},
60 { 0, NULL}
61 };
62
63 static const struct tok udld_flags_values[] = {
64 { 0x00, "RT"},
65 { 0x01, "RSY"},
66 { 0, NULL}
67 };
68
69 /*
70 *
71 * 0 1 2 3
72 * 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
73 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
74 * | Ver | Opcode | Flags | Checksum |
75 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
76 * | List of TLVs (variable length list) |
77 * | ... |
78 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
79 *
80 */
81
82 #define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
83 #define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f)
84
85 void
udld_print(const u_char * pptr,u_int length)86 udld_print (const u_char *pptr, u_int length)
87 {
88 int code, type, len;
89 const u_char *tptr;
90
91 if (length < UDLD_HEADER_LEN)
92 goto trunc;
93
94 tptr = pptr;
95
96 if (!TTEST2(*tptr, UDLD_HEADER_LEN))
97 goto trunc;
98
99 code = UDLD_EXTRACT_OPCODE(*tptr);
100
101 printf("UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u",
102 UDLD_EXTRACT_VERSION(*tptr),
103 tok2str(udld_code_values, "Reserved", code),
104 code,
105 bittok2str(udld_flags_values, "none", *(tptr+1)),
106 *(tptr+1),
107 length);
108
109 /*
110 * In non-verbose mode, just print version and opcode type
111 */
112 if (vflag < 1) {
113 return;
114 }
115
116 printf("\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2));
117
118 tptr += UDLD_HEADER_LEN;
119
120 while (tptr < (pptr+length)) {
121
122 if (!TTEST2(*tptr, 4))
123 goto trunc;
124
125 type = EXTRACT_16BITS(tptr);
126 len = EXTRACT_16BITS(tptr+2);
127 len -= 4;
128 tptr += 4;
129
130 /* infinite loop check */
131 if (type == 0 || len == 0) {
132 return;
133 }
134
135 printf("\n\t%s (0x%04x) TLV, length %u",
136 tok2str(udld_tlv_values, "Unknown", type),
137 type, len);
138
139 switch (type) {
140 case UDLD_DEVICE_ID_TLV:
141 case UDLD_PORT_ID_TLV:
142 case UDLD_ECHO_TLV:
143 case UDLD_DEVICE_NAME_TLV:
144 printf(", %s", tptr);
145 break;
146
147 case UDLD_MESSAGE_INTERVAL_TLV:
148 case UDLD_TIMEOUT_INTERVAL_TLV:
149 printf(", %us", (*tptr));
150 break;
151
152 case UDLD_SEQ_NUMBER_TLV:
153 printf(", %u", EXTRACT_32BITS(tptr));
154 break;
155
156 default:
157 break;
158 }
159 tptr += len;
160 }
161
162 return;
163
164 trunc:
165 printf("[|udld]");
166 }
167
168 /*
169 * Local Variables:
170 * c-style: whitesmith
171 * c-basic-offset: 4
172 * End:
173 */
174