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1 office 1 /*
2 * Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 *
21 * Code by Gert Doering, SpaceNet GmbH, gert@space.net
22 *
23 * Reference documentation:
24 * http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm
25 */
26  
27 #define NETDISSECT_REWORKED
28 #ifdef HAVE_CONFIG_H
29 #include "config.h"
30 #endif
31  
32 #include <tcpdump-stdinc.h>
33  
34 #include <string.h>
35  
36 #include "interface.h"
37 #include "addrtoname.h"
38 #include "extract.h" /* must come after interface.h */
39 #include "nlpid.h"
40  
41 static const char tstr[] = "[|cdp]";
42  
43 #define CDP_HEADER_LEN 4
44 #define CDP_HEADER_VERSION_OFFSET 0
45 #define CDP_HEADER_TTL_OFFSET 1
46 #define CDP_HEADER_CHECKSUM_OFFSET 2
47  
48 #define CDP_TLV_HEADER_LEN 4
49 #define CDP_TLV_TYPE_OFFSET 0
50 #define CDP_TLV_LEN_OFFSET 2
51  
52 static const struct tok cdp_tlv_values[] = {
53 { 0x01, "Device-ID"},
54 { 0x02, "Address"},
55 { 0x03, "Port-ID"},
56 { 0x04, "Capability"},
57 { 0x05, "Version String"},
58 { 0x06, "Platform"},
59 { 0x07, "Prefixes"},
60 { 0x08, "Protocol-Hello option"},
61 { 0x09, "VTP Management Domain"},
62 { 0x0a, "Native VLAN ID"},
63 { 0x0b, "Duplex"},
64 { 0x0e, "ATA-186 VoIP VLAN request"},
65 { 0x0f, "ATA-186 VoIP VLAN assignment"},
66 { 0x10, "power consumption"},
67 { 0x11, "MTU"},
68 { 0x12, "AVVID trust bitmap"},
69 { 0x13, "AVVID untrusted ports CoS"},
70 { 0x14, "System Name"},
71 { 0x15, "System Object ID (not decoded)"},
72 { 0x16, "Management Addresses"},
73 { 0x17, "Physical Location"},
74 { 0, NULL}
75 };
76  
77 static const struct tok cdp_capability_values[] = {
78 { 0x01, "Router" },
79 { 0x02, "Transparent Bridge" },
80 { 0x04, "Source Route Bridge" },
81 { 0x08, "L2 Switch" },
82 { 0x10, "L3 capable" },
83 { 0x20, "IGMP snooping" },
84 { 0x40, "L1 capable" },
85 { 0, NULL }
86 };
87  
88 static int cdp_print_addr(netdissect_options *, const u_char *, int);
89 static int cdp_print_prefixes(netdissect_options *, const u_char *, int);
90 static unsigned long cdp_get_number(const u_char *, int);
91  
92 void
93 cdp_print(netdissect_options *ndo,
94 const u_char *pptr, u_int length, u_int caplen)
95 {
96 int type, len, i, j;
97 const u_char *tptr;
98  
99 if (caplen < CDP_HEADER_LEN) {
100 ND_PRINT((ndo, "%s", tstr));
101 return;
102 }
103  
104 tptr = pptr; /* temporary pointer */
105  
106 ND_TCHECK2(*tptr, CDP_HEADER_LEN);
107 ND_PRINT((ndo, "CDPv%u, ttl: %us", *(tptr + CDP_HEADER_VERSION_OFFSET),
108 *(tptr + CDP_HEADER_TTL_OFFSET)));
109 if (ndo->ndo_vflag)
110 ND_PRINT((ndo, ", checksum: 0x%04x (unverified), length %u", EXTRACT_16BITS(tptr+CDP_HEADER_CHECKSUM_OFFSET), length));
111 tptr += CDP_HEADER_LEN;
112  
113 while (tptr < (pptr+length)) {
114 ND_TCHECK2(*tptr, CDP_TLV_HEADER_LEN); /* read out Type and Length */
115 type = EXTRACT_16BITS(tptr+CDP_TLV_TYPE_OFFSET);
116 len = EXTRACT_16BITS(tptr+CDP_TLV_LEN_OFFSET); /* object length includes the 4 bytes header length */
117 if (len < CDP_TLV_HEADER_LEN) {
118 if (ndo->ndo_vflag)
119 ND_PRINT((ndo, "\n\t%s (0x%02x), TLV length: %u byte%s (too short)",
120 tok2str(cdp_tlv_values,"unknown field type", type),
121 type,
122 len,
123 PLURAL_SUFFIX(len))); /* plural */
124 else
125 ND_PRINT((ndo, ", %s TLV length %u too short",
126 tok2str(cdp_tlv_values,"unknown field type", type),
127 len));
128 break;
129 }
130 tptr += CDP_TLV_HEADER_LEN;
131 len -= CDP_TLV_HEADER_LEN;
132  
133 ND_TCHECK2(*tptr, len);
134  
135 if (ndo->ndo_vflag || type == 1) { /* in non-verbose mode just print Device-ID */
136  
137 if (ndo->ndo_vflag)
138 ND_PRINT((ndo, "\n\t%s (0x%02x), value length: %u byte%s: ",
139 tok2str(cdp_tlv_values,"unknown field type", type),
140 type,
141 len,
142 PLURAL_SUFFIX(len))); /* plural */
143  
144 switch (type) {
145  
146 case 0x01: /* Device-ID */
147 if (!ndo->ndo_vflag)
148 ND_PRINT((ndo, ", Device-ID "));
149 ND_PRINT((ndo, "'"));
150 (void)fn_printn(ndo, tptr, len, NULL);
151 ND_PRINT((ndo, "'"));
152 break;
153 case 0x02: /* Address */
154 if (cdp_print_addr(ndo, tptr, len) < 0)
155 goto trunc;
156 break;
157 case 0x03: /* Port-ID */
158 ND_PRINT((ndo, "'"));
159 (void)fn_printn(ndo, tptr, len, NULL);
160 ND_PRINT((ndo, "'"));
161 break;
162 case 0x04: /* Capabilities */
163 if (len < 4)
164 goto trunc;
165 ND_PRINT((ndo, "(0x%08x): %s",
166 EXTRACT_32BITS(tptr),
167 bittok2str(cdp_capability_values, "none", EXTRACT_32BITS(tptr))));
168 break;
169 case 0x05: /* Version */
170 ND_PRINT((ndo, "\n\t "));
171 for (i=0;i<len;i++) {
172 j = *(tptr+i);
173 ND_PRINT((ndo, "%c", j));
174 if (j == 0x0a) /* lets rework the version string to get a nice indentation */
175 ND_PRINT((ndo, "\t "));
176 }
177 break;
178 case 0x06: /* Platform */
179 ND_PRINT((ndo, "'"));
180 (void)fn_printn(ndo, tptr, len, NULL);
181 ND_PRINT((ndo, "'"));
182 break;
183 case 0x07: /* Prefixes */
184 if (cdp_print_prefixes(ndo, tptr, len) < 0)
185 goto trunc;
186 break;
187 case 0x08: /* Protocol Hello Option - not documented */
188 break;
189 case 0x09: /* VTP Mgmt Domain - CDPv2 */
190 ND_PRINT((ndo, "'"));
191 (void)fn_printn(ndo, tptr, len, NULL);
192 ND_PRINT((ndo, "'"));
193 break;
194 case 0x0a: /* Native VLAN ID - CDPv2 */
195 if (len < 2)
196 goto trunc;
197 ND_PRINT((ndo, "%d", EXTRACT_16BITS(tptr)));
198 break;
199 case 0x0b: /* Duplex - CDPv2 */
200 if (len < 1)
201 goto trunc;
202 ND_PRINT((ndo, "%s", *(tptr) ? "full": "half"));
203 break;
204  
205 /* http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cata/186/2_12_m/english/release/notes/186rn21m.html
206 * plus more details from other sources
207 */
208 case 0x0e: /* ATA-186 VoIP VLAN request - incomplete doc. */
209 if (len < 3)
210 goto trunc;
211 ND_PRINT((ndo, "app %d, vlan %d", *(tptr), EXTRACT_16BITS(tptr + 1)));
212 break;
213 case 0x10: /* ATA-186 VoIP VLAN assignment - incomplete doc. */
214 ND_PRINT((ndo, "%1.2fW", cdp_get_number(tptr, len) / 1000.0));
215 break;
216 case 0x11: /* MTU - not documented */
217 if (len < 4)
218 goto trunc;
219 ND_PRINT((ndo, "%u bytes", EXTRACT_32BITS(tptr)));
220 break;
221 case 0x12: /* AVVID trust bitmap - not documented */
222 if (len < 1)
223 goto trunc;
224 ND_PRINT((ndo, "0x%02x", *(tptr)));
225 break;
226 case 0x13: /* AVVID untrusted port CoS - not documented */
227 if (len < 1)
228 goto trunc;
229 ND_PRINT((ndo, "0x%02x", *(tptr)));
230 break;
231 case 0x14: /* System Name - not documented */
232 ND_PRINT((ndo, "'"));
233 (void)fn_printn(ndo, tptr, len, NULL);
234 ND_PRINT((ndo, "'"));
235 break;
236 case 0x16: /* System Object ID - not documented */
237 if (cdp_print_addr(ndo, tptr, len) < 0)
238 goto trunc;
239 break;
240 case 0x17: /* Physical Location - not documented */
241 if (len < 1)
242 goto trunc;
243 ND_PRINT((ndo, "0x%02x", *(tptr)));
244 if (len > 1) {
245 ND_PRINT((ndo, "/"));
246 (void)fn_printn(ndo, tptr + 1, len - 1, NULL);
247 }
248 break;
249 default:
250 print_unknown_data(ndo, tptr, "\n\t ", len);
251 break;
252 }
253 }
254 tptr = tptr+len;
255 }
256 if (ndo->ndo_vflag < 1)
257 ND_PRINT((ndo, ", length %u", caplen));
258  
259 return;
260 trunc:
261 ND_PRINT((ndo, "%s", tstr));
262 }
263  
264 /*
265 * Protocol type values.
266 *
267 * PT_NLPID means that the protocol type field contains an OSI NLPID.
268 *
269 * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2
270 * LLC header that specifies that the payload is for that protocol.
271 */
272 #define PT_NLPID 1 /* OSI NLPID */
273 #define PT_IEEE_802_2 2 /* IEEE 802.2 LLC header */
274  
275 static int
276 cdp_print_addr(netdissect_options *ndo,
277 const u_char * p, int l)
278 {
279 int pt, pl, al, num;
280 const u_char *endp = p + l;
281 #ifdef INET6
282 static const u_char prot_ipv6[] = {
283 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
284 };
285 #endif
286  
287 ND_TCHECK2(*p, 4);
288 if (p + 4 > endp)
289 goto trunc;
290 num = EXTRACT_32BITS(p);
291 p += 4;
292  
293 while (p < endp && num >= 0) {
294 ND_TCHECK2(*p, 2);
295 if (p + 2 > endp)
296 goto trunc;
297 pt = p[0]; /* type of "protocol" field */
298 pl = p[1]; /* length of "protocol" field */
299 p += 2;
300  
301 ND_TCHECK2(p[pl], 2);
302 if (p + pl + 2 > endp)
303 goto trunc;
304 al = EXTRACT_16BITS(&p[pl]); /* address length */
305  
306 if (pt == PT_NLPID && pl == 1 && *p == NLPID_IP && al == 4) {
307 /*
308 * IPv4: protocol type = NLPID, protocol length = 1
309 * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4),
310 * address length = 4
311 */
312 p += 3;
313  
314 ND_TCHECK2(*p, 4);
315 if (p + 4 > endp)
316 goto trunc;
317 ND_PRINT((ndo, "IPv4 (%u) %s", num, ipaddr_string(ndo, p)));
318 p += 4;
319 }
320 #ifdef INET6
321 else if (pt == PT_IEEE_802_2 && pl == 8 &&
322 memcmp(p, prot_ipv6, 8) == 0 && al == 16) {
323 /*
324 * IPv6: protocol type = IEEE 802.2 header,
325 * protocol length = 8 (size of LLC+SNAP header),
326 * protocol = LLC+SNAP header with the IPv6
327 * Ethertype, address length = 16
328 */
329 p += 10;
330 ND_TCHECK2(*p, al);
331 if (p + al > endp)
332 goto trunc;
333  
334 ND_PRINT((ndo, "IPv6 (%u) %s", num, ip6addr_string(ndo, p)));
335 p += al;
336 }
337 #endif
338 else {
339 /*
340 * Generic case: just print raw data
341 */
342 ND_TCHECK2(*p, pl);
343 if (p + pl > endp)
344 goto trunc;
345 ND_PRINT((ndo, "pt=0x%02x, pl=%d, pb=", *(p - 2), pl));
346 while (pl-- > 0)
347 ND_PRINT((ndo, " %02x", *p++));
348 ND_TCHECK2(*p, 2);
349 if (p + 2 > endp)
350 goto trunc;
351 al = (*p << 8) + *(p + 1);
352 ND_PRINT((ndo, ", al=%d, a=", al));
353 p += 2;
354 ND_TCHECK2(*p, al);
355 if (p + al > endp)
356 goto trunc;
357 while (al-- > 0)
358 ND_PRINT((ndo, " %02x", *p++));
359 }
360 num--;
361 if (num)
362 ND_PRINT((ndo, " "));
363 }
364  
365 return 0;
366  
367 trunc:
368 return -1;
369 }
370  
371  
372 static int
373 cdp_print_prefixes(netdissect_options *ndo,
374 const u_char * p, int l)
375 {
376 if (l % 5)
377 goto trunc;
378  
379 ND_PRINT((ndo, " IPv4 Prefixes (%d):", l / 5));
380  
381 while (l > 0) {
382 ND_PRINT((ndo, " %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4]));
383 l -= 5;
384 p += 5;
385 }
386  
387 return 0;
388  
389 trunc:
390 return -1;
391 }
392  
393 /* read in a <n>-byte number, MSB first
394 * (of course this can handle max sizeof(long))
395 */
396 static unsigned long cdp_get_number(const u_char * p, int l)
397 {
398 unsigned long res=0;
399 while( l>0 )
400 {
401 res = (res<<8) + *p;
402 p++; l--;
403 }
404 return res;
405 }