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 /* \summary: Cisco Discovery Protocol (CDP) printer */
28
29 #ifdef HAVE_CONFIG_H
30 #include "config.h"
31 #endif
32
33 #include <netdissect-stdinc.h>
34
35 #include <string.h>
36
37 #include "netdissect.h"
38 #include "addrtoname.h"
39 #include "extract.h"
40 #include "nlpid.h"
41
42 static const char tstr[] = "[|cdp]";
43
44 #define CDP_HEADER_LEN 4
45 #define CDP_HEADER_VERSION_OFFSET 0
46 #define CDP_HEADER_TTL_OFFSET 1
47 #define CDP_HEADER_CHECKSUM_OFFSET 2
48
49 #define CDP_TLV_HEADER_LEN 4
50 #define CDP_TLV_TYPE_OFFSET 0
51 #define CDP_TLV_LEN_OFFSET 2
52
53 static const struct tok cdp_tlv_values[] = {
54 { 0x01, "Device-ID"},
55 { 0x02, "Address"},
56 { 0x03, "Port-ID"},
57 { 0x04, "Capability"},
58 { 0x05, "Version String"},
59 { 0x06, "Platform"},
60 { 0x07, "Prefixes"},
61 { 0x08, "Protocol-Hello option"},
62 { 0x09, "VTP Management Domain"},
63 { 0x0a, "Native VLAN ID"},
64 { 0x0b, "Duplex"},
65 { 0x0e, "ATA-186 VoIP VLAN request"},
66 { 0x0f, "ATA-186 VoIP VLAN assignment"},
67 { 0x10, "power consumption"},
68 { 0x11, "MTU"},
69 { 0x12, "AVVID trust bitmap"},
70 { 0x13, "AVVID untrusted ports CoS"},
71 { 0x14, "System Name"},
72 { 0x15, "System Object ID (not decoded)"},
73 { 0x16, "Management Addresses"},
74 { 0x17, "Physical Location"},
75 { 0, NULL}
76 };
77
78 static const struct tok cdp_capability_values[] = {
79 { 0x01, "Router" },
80 { 0x02, "Transparent Bridge" },
81 { 0x04, "Source Route Bridge" },
82 { 0x08, "L2 Switch" },
83 { 0x10, "L3 capable" },
84 { 0x20, "IGMP snooping" },
85 { 0x40, "L1 capable" },
86 { 0, NULL }
87 };
88
89 static int cdp_print_addr(netdissect_options *, const u_char *, int);
90 static int cdp_print_prefixes(netdissect_options *, const u_char *, int);
91 static unsigned long cdp_get_number(const u_char *, int);
92
93 void
cdp_print(netdissect_options * ndo,const u_char * pptr,u_int length,u_int caplen)94 cdp_print(netdissect_options *ndo,
95 const u_char *pptr, u_int length, u_int caplen)
96 {
97 int type, len, i, j;
98 const u_char *tptr;
99
100 if (caplen < CDP_HEADER_LEN) {
101 ND_PRINT((ndo, "%s", tstr));
102 return;
103 }
104
105 tptr = pptr; /* temporary pointer */
106
107 ND_TCHECK2(*tptr, CDP_HEADER_LEN);
108 ND_PRINT((ndo, "CDPv%u, ttl: %us", *(tptr + CDP_HEADER_VERSION_OFFSET),
109 *(tptr + CDP_HEADER_TTL_OFFSET)));
110 if (ndo->ndo_vflag)
111 ND_PRINT((ndo, ", checksum: 0x%04x (unverified), length %u", EXTRACT_16BITS(tptr+CDP_HEADER_CHECKSUM_OFFSET), length));
112 tptr += CDP_HEADER_LEN;
113
114 while (tptr < (pptr+length)) {
115 ND_TCHECK2(*tptr, CDP_TLV_HEADER_LEN); /* read out Type and Length */
116 type = EXTRACT_16BITS(tptr+CDP_TLV_TYPE_OFFSET);
117 len = EXTRACT_16BITS(tptr+CDP_TLV_LEN_OFFSET); /* object length includes the 4 bytes header length */
118 if (len < CDP_TLV_HEADER_LEN) {
119 if (ndo->ndo_vflag)
120 ND_PRINT((ndo, "\n\t%s (0x%02x), TLV length: %u byte%s (too short)",
121 tok2str(cdp_tlv_values,"unknown field type", type),
122 type,
123 len,
124 PLURAL_SUFFIX(len))); /* plural */
125 else
126 ND_PRINT((ndo, ", %s TLV length %u too short",
127 tok2str(cdp_tlv_values,"unknown field type", type),
128 len));
129 break;
130 }
131 tptr += CDP_TLV_HEADER_LEN;
132 len -= CDP_TLV_HEADER_LEN;
133
134 ND_TCHECK2(*tptr, len);
135
136 if (ndo->ndo_vflag || type == 1) { /* in non-verbose mode just print Device-ID */
137
138 if (ndo->ndo_vflag)
139 ND_PRINT((ndo, "\n\t%s (0x%02x), value length: %u byte%s: ",
140 tok2str(cdp_tlv_values,"unknown field type", type),
141 type,
142 len,
143 PLURAL_SUFFIX(len))); /* plural */
144
145 switch (type) {
146
147 case 0x01: /* Device-ID */
148 if (!ndo->ndo_vflag)
149 ND_PRINT((ndo, ", Device-ID "));
150 ND_PRINT((ndo, "'"));
151 (void)fn_printn(ndo, tptr, len, NULL);
152 ND_PRINT((ndo, "'"));
153 break;
154 case 0x02: /* Address */
155 if (cdp_print_addr(ndo, tptr, len) < 0)
156 goto trunc;
157 break;
158 case 0x03: /* Port-ID */
159 ND_PRINT((ndo, "'"));
160 (void)fn_printn(ndo, tptr, len, NULL);
161 ND_PRINT((ndo, "'"));
162 break;
163 case 0x04: /* Capabilities */
164 if (len < 4)
165 goto trunc;
166 ND_PRINT((ndo, "(0x%08x): %s",
167 EXTRACT_32BITS(tptr),
168 bittok2str(cdp_capability_values, "none", EXTRACT_32BITS(tptr))));
169 break;
170 case 0x05: /* Version */
171 ND_PRINT((ndo, "\n\t "));
172 for (i=0;i<len;i++) {
173 j = *(tptr+i);
174 if (j == '\n') /* lets rework the version string to
175 get a nice indentation */
176 ND_PRINT((ndo, "\n\t "));
177 else
178 fn_print_char(ndo, j);
179 }
180 break;
181 case 0x06: /* Platform */
182 ND_PRINT((ndo, "'"));
183 (void)fn_printn(ndo, tptr, len, NULL);
184 ND_PRINT((ndo, "'"));
185 break;
186 case 0x07: /* Prefixes */
187 if (cdp_print_prefixes(ndo, tptr, len) < 0)
188 goto trunc;
189 break;
190 case 0x08: /* Protocol Hello Option - not documented */
191 break;
192 case 0x09: /* VTP Mgmt Domain - CDPv2 */
193 ND_PRINT((ndo, "'"));
194 (void)fn_printn(ndo, tptr, len, NULL);
195 ND_PRINT((ndo, "'"));
196 break;
197 case 0x0a: /* Native VLAN ID - CDPv2 */
198 if (len < 2)
199 goto trunc;
200 ND_PRINT((ndo, "%d", EXTRACT_16BITS(tptr)));
201 break;
202 case 0x0b: /* Duplex - CDPv2 */
203 if (len < 1)
204 goto trunc;
205 ND_PRINT((ndo, "%s", *(tptr) ? "full": "half"));
206 break;
207
208 /* http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cata/186/2_12_m/english/release/notes/186rn21m.html
209 * plus more details from other sources
210 */
211 case 0x0e: /* ATA-186 VoIP VLAN request - incomplete doc. */
212 if (len < 3)
213 goto trunc;
214 ND_PRINT((ndo, "app %d, vlan %d", *(tptr), EXTRACT_16BITS(tptr + 1)));
215 break;
216 case 0x10: /* ATA-186 VoIP VLAN assignment - incomplete doc. */
217 ND_PRINT((ndo, "%1.2fW", cdp_get_number(tptr, len) / 1000.0));
218 break;
219 case 0x11: /* MTU - not documented */
220 if (len < 4)
221 goto trunc;
222 ND_PRINT((ndo, "%u bytes", EXTRACT_32BITS(tptr)));
223 break;
224 case 0x12: /* AVVID trust bitmap - not documented */
225 if (len < 1)
226 goto trunc;
227 ND_PRINT((ndo, "0x%02x", *(tptr)));
228 break;
229 case 0x13: /* AVVID untrusted port CoS - not documented */
230 if (len < 1)
231 goto trunc;
232 ND_PRINT((ndo, "0x%02x", *(tptr)));
233 break;
234 case 0x14: /* System Name - not documented */
235 ND_PRINT((ndo, "'"));
236 (void)fn_printn(ndo, tptr, len, NULL);
237 ND_PRINT((ndo, "'"));
238 break;
239 case 0x16: /* System Object ID - not documented */
240 if (cdp_print_addr(ndo, tptr, len) < 0)
241 goto trunc;
242 break;
243 case 0x17: /* Physical Location - not documented */
244 if (len < 1)
245 goto trunc;
246 ND_PRINT((ndo, "0x%02x", *(tptr)));
247 if (len > 1) {
248 ND_PRINT((ndo, "/"));
249 (void)fn_printn(ndo, tptr + 1, len - 1, NULL);
250 }
251 break;
252 default:
253 print_unknown_data(ndo, tptr, "\n\t ", len);
254 break;
255 }
256 }
257 tptr = tptr+len;
258 }
259 if (ndo->ndo_vflag < 1)
260 ND_PRINT((ndo, ", length %u", caplen));
261
262 return;
263 trunc:
264 ND_PRINT((ndo, "%s", tstr));
265 }
266
267 /*
268 * Protocol type values.
269 *
270 * PT_NLPID means that the protocol type field contains an OSI NLPID.
271 *
272 * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2
273 * LLC header that specifies that the payload is for that protocol.
274 */
275 #define PT_NLPID 1 /* OSI NLPID */
276 #define PT_IEEE_802_2 2 /* IEEE 802.2 LLC header */
277
278 static int
cdp_print_addr(netdissect_options * ndo,const u_char * p,int l)279 cdp_print_addr(netdissect_options *ndo,
280 const u_char * p, int l)
281 {
282 int pt, pl, al, num;
283 const u_char *endp = p + l;
284 static const u_char prot_ipv6[] = {
285 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd
286 };
287
288 ND_TCHECK2(*p, 4);
289 if (p + 4 > endp)
290 goto trunc;
291 num = EXTRACT_32BITS(p);
292 p += 4;
293
294 while (p < endp && num >= 0) {
295 ND_TCHECK2(*p, 2);
296 if (p + 2 > endp)
297 goto trunc;
298 pt = p[0]; /* type of "protocol" field */
299 pl = p[1]; /* length of "protocol" field */
300 p += 2;
301
302 ND_TCHECK2(p[pl], 2);
303 if (p + pl + 2 > endp)
304 goto trunc;
305 al = EXTRACT_16BITS(&p[pl]); /* address length */
306
307 if (pt == PT_NLPID && pl == 1 && *p == NLPID_IP && al == 4) {
308 /*
309 * IPv4: protocol type = NLPID, protocol length = 1
310 * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4),
311 * address length = 4
312 */
313 p += 3;
314
315 ND_TCHECK2(*p, 4);
316 if (p + 4 > endp)
317 goto trunc;
318 ND_PRINT((ndo, "IPv4 (%u) %s", num, ipaddr_string(ndo, p)));
319 p += 4;
320 }
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 else {
338 /*
339 * Generic case: just print raw data
340 */
341 ND_TCHECK2(*p, pl);
342 if (p + pl > endp)
343 goto trunc;
344 ND_PRINT((ndo, "pt=0x%02x, pl=%d, pb=", *(p - 2), pl));
345 while (pl-- > 0)
346 ND_PRINT((ndo, " %02x", *p++));
347 ND_TCHECK2(*p, 2);
348 if (p + 2 > endp)
349 goto trunc;
350 al = (*p << 8) + *(p + 1);
351 ND_PRINT((ndo, ", al=%d, a=", al));
352 p += 2;
353 ND_TCHECK2(*p, al);
354 if (p + al > endp)
355 goto trunc;
356 while (al-- > 0)
357 ND_PRINT((ndo, " %02x", *p++));
358 }
359 num--;
360 if (num)
361 ND_PRINT((ndo, " "));
362 }
363
364 return 0;
365
366 trunc:
367 return -1;
368 }
369
370
371 static int
cdp_print_prefixes(netdissect_options * ndo,const u_char * p,int l)372 cdp_print_prefixes(netdissect_options *ndo,
373 const u_char * p, int l)
374 {
375 if (l % 5)
376 goto trunc;
377
378 ND_PRINT((ndo, " IPv4 Prefixes (%d):", l / 5));
379
380 while (l > 0) {
381 ND_PRINT((ndo, " %u.%u.%u.%u/%u", p[0], p[1], p[2], p[3], p[4]));
382 l -= 5;
383 p += 5;
384 }
385
386 return 0;
387
388 trunc:
389 return -1;
390 }
391
392 /* read in a <n>-byte number, MSB first
393 * (of course this can handle max sizeof(long))
394 */
cdp_get_number(const u_char * p,int l)395 static unsigned long cdp_get_number(const u_char * p, int l)
396 {
397 unsigned long res=0;
398 while( l>0 )
399 {
400 res = (res<<8) + *p;
401 p++; l--;
402 }
403 return res;
404 }
405