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 Matt Thomas, Digital Equipment Corporation
22  *	with an awful lot of hacking by Jeffrey Mogul, DECWRL
23  */
24 
25 #define NETDISSECT_REWORKED
26 #ifdef HAVE_CONFIG_H
27 #include "config.h"
28 #endif
29 
30 #include <tcpdump-stdinc.h>
31 
32 #include "interface.h"
33 #include "addrtoname.h"
34 #include "extract.h"			/* must come after interface.h */
35 
36 #include "llc.h"
37 #include "ethertype.h"
38 #include "oui.h"
39 
40 static const struct tok llc_values[] = {
41         { LLCSAP_NULL,     "Null" },
42         { LLCSAP_GLOBAL,   "Global" },
43         { LLCSAP_8021B_I,  "802.1B I" },
44         { LLCSAP_8021B_G,  "802.1B G" },
45         { LLCSAP_IP,       "IP" },
46         { LLCSAP_SNA,      "SNA" },
47         { LLCSAP_PROWAYNM, "ProWay NM" },
48         { LLCSAP_8021D,    "STP" },
49         { LLCSAP_RS511,    "RS511" },
50         { LLCSAP_ISO8208,  "ISO8208" },
51         { LLCSAP_PROWAY,   "ProWay" },
52         { LLCSAP_SNAP,     "SNAP" },
53         { LLCSAP_IPX,      "IPX" },
54         { LLCSAP_NETBEUI,  "NetBeui" },
55         { LLCSAP_ISONS,    "OSI" },
56         { 0,               NULL },
57 };
58 
59 static const struct tok llc_cmd_values[] = {
60 	{ LLC_UI,	"ui" },
61 	{ LLC_TEST,	"test" },
62 	{ LLC_XID,	"xid" },
63 	{ LLC_UA,	"ua" },
64 	{ LLC_DISC,	"disc" },
65 	{ LLC_DM,	"dm" },
66 	{ LLC_SABME,	"sabme" },
67 	{ LLC_FRMR,	"frmr" },
68 	{ 0,		NULL }
69 };
70 
71 static const struct tok llc_flag_values[] = {
72         { 0, "Command" },
73         { LLC_GSAP, "Response" },
74         { LLC_U_POLL, "Poll" },
75         { LLC_GSAP|LLC_U_POLL, "Final" },
76         { LLC_IS_POLL, "Poll" },
77         { LLC_GSAP|LLC_IS_POLL, "Final" },
78 	{ 0, NULL }
79 };
80 
81 
82 static const struct tok llc_ig_flag_values[] = {
83         { 0, "Individual" },
84         { LLC_IG, "Group" },
85 	{ 0, NULL }
86 };
87 
88 
89 static const struct tok llc_supervisory_values[] = {
90         { 0, "Receiver Ready" },
91         { 1, "Receiver not Ready" },
92         { 2, "Reject" },
93 	{ 0,             NULL }
94 };
95 
96 
97 static const struct tok cisco_values[] = {
98 	{ PID_CISCO_CDP, "CDP" },
99 	{ PID_CISCO_VTP, "VTP" },
100 	{ PID_CISCO_DTP, "DTP" },
101 	{ PID_CISCO_UDLD, "UDLD" },
102 	{ PID_CISCO_PVST, "PVST" },
103 	{ PID_CISCO_VLANBRIDGE, "VLAN Bridge" },
104 	{ 0,             NULL }
105 };
106 
107 static const struct tok bridged_values[] = {
108 	{ PID_RFC2684_ETH_FCS,     "Ethernet + FCS" },
109 	{ PID_RFC2684_ETH_NOFCS,   "Ethernet w/o FCS" },
110 	{ PID_RFC2684_802_4_FCS,   "802.4 + FCS" },
111 	{ PID_RFC2684_802_4_NOFCS, "802.4 w/o FCS" },
112 	{ PID_RFC2684_802_5_FCS,   "Token Ring + FCS" },
113 	{ PID_RFC2684_802_5_NOFCS, "Token Ring w/o FCS" },
114 	{ PID_RFC2684_FDDI_FCS,    "FDDI + FCS" },
115 	{ PID_RFC2684_FDDI_NOFCS,  "FDDI w/o FCS" },
116 	{ PID_RFC2684_802_6_FCS,   "802.6 + FCS" },
117 	{ PID_RFC2684_802_6_NOFCS, "802.6 w/o FCS" },
118 	{ PID_RFC2684_BPDU,        "BPDU" },
119 	{ 0,                       NULL },
120 };
121 
122 static const struct tok null_values[] = {
123 	{ 0,             NULL }
124 };
125 
126 struct oui_tok {
127 	uint32_t	oui;
128 	const struct tok *tok;
129 };
130 
131 static const struct oui_tok oui_to_tok[] = {
132 	{ OUI_ENCAP_ETHER, ethertype_values },
133 	{ OUI_CISCO_90, ethertype_values },	/* uses some Ethertype values */
134 	{ OUI_APPLETALK, ethertype_values },	/* uses some Ethertype values */
135 	{ OUI_CISCO, cisco_values },
136 	{ OUI_RFC2684, bridged_values },	/* bridged, RFC 2427 FR or RFC 2864 ATM */
137 	{ 0, NULL }
138 };
139 
140 /*
141  * Returns non-zero IFF it succeeds in printing the header
142  */
143 int
llc_print(netdissect_options * ndo,const u_char * p,u_int length,u_int caplen,const u_char * esrc,const u_char * edst,u_short * extracted_ethertype)144 llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
145 	  const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
146 {
147 	uint8_t dsap_field, dsap, ssap_field, ssap;
148 	uint16_t control;
149 	int is_u;
150 	register int ret;
151 
152 	*extracted_ethertype = 0;
153 
154 	if (caplen < 3 || length < 3) {
155 		ND_PRINT((ndo, "[|llc]"));
156 		ND_DEFAULTPRINT((u_char *)p, caplen);
157 		return (1);
158 	}
159 
160 	dsap_field = *p;
161 	ssap_field = *(p + 1);
162 
163 	/*
164 	 * OK, what type of LLC frame is this?  The length
165 	 * of the control field depends on that - I frames
166 	 * have a two-byte control field, and U frames have
167 	 * a one-byte control field.
168 	 */
169 	control = *(p + 2);
170 	if ((control & LLC_U_FMT) == LLC_U_FMT) {
171 		/*
172 		 * U frame.
173 		 */
174 		is_u = 1;
175 	} else {
176 		/*
177 		 * The control field in I and S frames is
178 		 * 2 bytes...
179 		 */
180 		if (caplen < 4 || length < 4) {
181 			ND_PRINT((ndo, "[|llc]"));
182 			ND_DEFAULTPRINT((u_char *)p, caplen);
183 			return (1);
184 		}
185 
186 		/*
187 		 * ...and is little-endian.
188 		 */
189 		control = EXTRACT_LE_16BITS(p + 2);
190 		is_u = 0;
191 	}
192 
193 	if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
194 		/*
195 		 * This is an Ethernet_802.3 IPX frame; it has an
196 		 * 802.3 header (i.e., an Ethernet header where the
197 		 * type/length field is <= ETHERMTU, i.e. it's a length
198 		 * field, not a type field), but has no 802.2 header -
199 		 * the IPX packet starts right after the Ethernet header,
200 		 * with a signature of two bytes of 0xFF (which is
201 		 * LLCSAP_GLOBAL).
202 		 *
203 		 * (It might also have been an Ethernet_802.3 IPX at
204 		 * one time, but got bridged onto another network,
205 		 * such as an 802.11 network; this has appeared in at
206 		 * least one capture file.)
207 		 */
208 
209             if (ndo->ndo_eflag)
210 		ND_PRINT((ndo, "IPX 802.3: "));
211 
212             ipx_print(ndo, p, length);
213             return (1);
214 	}
215 
216 	dsap = dsap_field & ~LLC_IG;
217 	ssap = ssap_field & ~LLC_GSAP;
218 
219 	if (ndo->ndo_eflag) {
220                 ND_PRINT((ndo, "LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
221                        tok2str(llc_values, "Unknown", dsap),
222                        dsap,
223                        tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
224                        tok2str(llc_values, "Unknown", ssap),
225                        ssap,
226                        tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP)));
227 
228 		if (is_u) {
229 			ND_PRINT((ndo, ", ctrl 0x%02x: ", control));
230 		} else {
231 			ND_PRINT((ndo, ", ctrl 0x%04x: ", control));
232 		}
233 	}
234 
235 	if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
236 	    control == LLC_UI) {
237 		stp_print(ndo, p+3, length-3);
238 		return (1);
239 	}
240 
241 	if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
242 	    control == LLC_UI) {
243 		if (caplen < 4 || length < 4) {
244 			ND_PRINT((ndo, "[|llc]"));
245 			ND_DEFAULTPRINT((u_char *)p, caplen);
246 			return (1);
247 		}
248 		ip_print(ndo, p+4, length-4);
249 		return (1);
250 	}
251 
252 	if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
253 	    control == LLC_UI) {
254 		/*
255 		 * This is an Ethernet_802.2 IPX frame, with an 802.3
256 		 * header and an 802.2 LLC header with the source and
257 		 * destination SAPs being the IPX SAP.
258 		 *
259 		 * Skip DSAP, LSAP, and control field.
260 		 */
261                 if (ndo->ndo_eflag)
262                         ND_PRINT((ndo, "IPX 802.2: "));
263 
264 		ipx_print(ndo, p+3, length-3);
265 		return (1);
266 	}
267 
268 #ifdef TCPDUMP_DO_SMB
269 	if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
270 	    && (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
271 		/*
272 		 * we don't actually have a full netbeui parser yet, but the
273 		 * smb parser can handle many smb-in-netbeui packets, which
274 		 * is very useful, so we call that
275 		 *
276 		 * We don't call it for S frames, however, just I frames
277 		 * (which are frames that don't have the low-order bit,
278 		 * LLC_S_FMT, set in the first byte of the control field)
279 		 * and UI frames (whose control field is just 3, LLC_U_FMT).
280 		 */
281 
282 		/*
283 		 * Skip the LLC header.
284 		 */
285 		if (is_u) {
286 			p += 3;
287 			length -= 3;
288 		} else {
289 			p += 4;
290 			length -= 4;
291 		}
292 		netbeui_print(ndo, control, p, length);
293 		return (1);
294 	}
295 #endif
296 	if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
297 	    && control == LLC_UI) {
298 		isoclns_print(ndo, p + 3, length - 3, caplen - 3);
299 		return (1);
300 	}
301 
302 	if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
303 	    && control == LLC_UI) {
304 		/*
305 		 * XXX - what *is* the right bridge pad value here?
306 		 * Does anybody ever bridge one form of LAN traffic
307 		 * over a networking type that uses 802.2 LLC?
308 		 */
309 		ret = snap_print(ndo, p+3, length-3, caplen-3, 2);
310 		if (ret)
311 			return (ret);
312 	}
313 
314 	if (!ndo->ndo_eflag) {
315 		if (ssap == dsap) {
316 			if (esrc == NULL || edst == NULL)
317 				ND_PRINT((ndo, "%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
318 			else
319 				ND_PRINT((ndo, "%s > %s %s ",
320 						etheraddr_string(ndo, esrc),
321 						etheraddr_string(ndo, edst),
322 						tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
323 		} else {
324 			if (esrc == NULL || edst == NULL)
325 				ND_PRINT((ndo, "%s > %s ",
326                                         tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
327 					tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
328 			else
329 				ND_PRINT((ndo, "%s %s > %s %s ",
330 					etheraddr_string(ndo, esrc),
331                                         tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
332 					etheraddr_string(ndo, edst),
333 					tok2str(llc_values, "Unknown DSAP 0x%02x", dsap)));
334 		}
335 	}
336 
337 	if (is_u) {
338 		ND_PRINT((ndo, "Unnumbered, %s, Flags [%s], length %u",
339                        tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
340                        tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
341                        length));
342 
343 		p += 3;
344 
345 		if ((control & ~LLC_U_POLL) == LLC_XID) {
346 			if (*p == LLC_XID_FI) {
347 				ND_PRINT((ndo, ": %02x %02x", p[1], p[2]));
348 			}
349 		}
350 	} else {
351 		if ((control & LLC_S_FMT) == LLC_S_FMT) {
352 			ND_PRINT((ndo, "Supervisory, %s, rcv seq %u, Flags [%s], length %u",
353 				tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
354 				LLC_IS_NR(control),
355 				tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
356                                 length));
357 		} else {
358 			ND_PRINT((ndo, "Information, send seq %u, rcv seq %u, Flags [%s], length %u",
359 				LLC_I_NS(control),
360 				LLC_IS_NR(control),
361 				tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
362                                 length));
363 		}
364 	}
365 	return(1);
366 }
367 
368 int
snap_print(netdissect_options * ndo,const u_char * p,u_int length,u_int caplen,u_int bridge_pad)369 snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
370 {
371 	uint32_t orgcode;
372 	register u_short et;
373 	register int ret;
374 
375 	ND_TCHECK2(*p, 5);
376 	if (caplen < 5 || length < 5)
377 		goto trunc;
378 	orgcode = EXTRACT_24BITS(p);
379 	et = EXTRACT_16BITS(p + 3);
380 
381 	if (ndo->ndo_eflag) {
382 		const struct tok *tok = null_values;
383 		const struct oui_tok *otp;
384 
385 		for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
386 			if (otp->oui == orgcode) {
387 				tok = otp->tok;
388 				break;
389 			}
390 		}
391 		ND_PRINT((ndo, "oui %s (0x%06x), %s %s (0x%04x): ",
392 		     tok2str(oui_values, "Unknown", orgcode),
393 		     orgcode,
394 		     (orgcode == 0x000000 ? "ethertype" : "pid"),
395 		     tok2str(tok, "Unknown", et),
396 		     et));
397 	}
398 	p += 5;
399 	length -= 5;
400 	caplen -= 5;
401 
402 	switch (orgcode) {
403 	case OUI_ENCAP_ETHER:
404 	case OUI_CISCO_90:
405 		/*
406 		 * This is an encapsulated Ethernet packet,
407 		 * or a packet bridged by some piece of
408 		 * Cisco hardware; the protocol ID is
409 		 * an Ethernet protocol type.
410 		 */
411 		ret = ethertype_print(ndo, et, p, length, caplen);
412 		if (ret)
413 			return (ret);
414 		break;
415 
416 	case OUI_APPLETALK:
417 		if (et == ETHERTYPE_ATALK) {
418 			/*
419 			 * No, I have no idea why Apple used one
420 			 * of their own OUIs, rather than
421 			 * 0x000000, and an Ethernet packet
422 			 * type, for Appletalk data packets,
423 			 * but used 0x000000 and an Ethernet
424 			 * packet type for AARP packets.
425 			 */
426 			ret = ethertype_print(ndo, et, p, length, caplen);
427 			if (ret)
428 				return (ret);
429 		}
430 		break;
431 
432 	case OUI_CISCO:
433                 switch (et) {
434                 case PID_CISCO_CDP:
435                         cdp_print(ndo, p, length, caplen);
436                         return (1);
437                 case PID_CISCO_DTP:
438                         dtp_print(ndo, p, length);
439                         return (1);
440                 case PID_CISCO_UDLD:
441                         udld_print(ndo, p, length);
442                         return (1);
443                 case PID_CISCO_VTP:
444                         vtp_print(ndo, p, length);
445                         return (1);
446                 case PID_CISCO_PVST:
447                 case PID_CISCO_VLANBRIDGE:
448                         stp_print(ndo, p, length);
449                         return (1);
450                 default:
451                         break;
452                 }
453 		break;
454 
455 	case OUI_RFC2684:
456 		switch (et) {
457 
458 		case PID_RFC2684_ETH_FCS:
459 		case PID_RFC2684_ETH_NOFCS:
460 			/*
461 			 * XXX - remove the last two bytes for
462 			 * PID_RFC2684_ETH_FCS?
463 			 */
464 			/*
465 			 * Skip the padding.
466 			 */
467 			ND_TCHECK2(*p, bridge_pad);
468 			caplen -= bridge_pad;
469 			length -= bridge_pad;
470 			p += bridge_pad;
471 
472 			/*
473 			 * What remains is an Ethernet packet.
474 			 */
475 			ether_print(ndo, p, length, caplen, NULL, NULL);
476 			return (1);
477 
478 		case PID_RFC2684_802_5_FCS:
479 		case PID_RFC2684_802_5_NOFCS:
480 			/*
481 			 * XXX - remove the last two bytes for
482 			 * PID_RFC2684_ETH_FCS?
483 			 */
484 			/*
485 			 * Skip the padding, but not the Access
486 			 * Control field.
487 			 */
488 			ND_TCHECK2(*p, bridge_pad);
489 			caplen -= bridge_pad;
490 			length -= bridge_pad;
491 			p += bridge_pad;
492 
493 			/*
494 			 * What remains is an 802.5 Token Ring
495 			 * packet.
496 			 */
497 			token_print(ndo, p, length, caplen);
498 			return (1);
499 
500 		case PID_RFC2684_FDDI_FCS:
501 		case PID_RFC2684_FDDI_NOFCS:
502 			/*
503 			 * XXX - remove the last two bytes for
504 			 * PID_RFC2684_ETH_FCS?
505 			 */
506 			/*
507 			 * Skip the padding.
508 			 */
509 			ND_TCHECK2(*p, bridge_pad + 1);
510 			caplen -= bridge_pad + 1;
511 			length -= bridge_pad + 1;
512 			p += bridge_pad + 1;
513 
514 			/*
515 			 * What remains is an FDDI packet.
516 			 */
517 			fddi_print(ndo, p, length, caplen);
518 			return (1);
519 
520 		case PID_RFC2684_BPDU:
521 			stp_print(ndo, p, length);
522 			return (1);
523 		}
524 	}
525 	return (0);
526 
527 trunc:
528 	ND_PRINT((ndo, "[|snap]"));
529 	return (1);
530 }
531 
532 
533 /*
534  * Local Variables:
535  * c-style: whitesmith
536  * c-basic-offset: 8
537  * End:
538  */
539