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 /* \summary: IEEE 802.2 LLC printer */
26
27 #include <config.h>
28
29 #include "netdissect-stdinc.h"
30
31 #include "netdissect.h"
32 #include "addrtoname.h"
33 #include "extract.h"
34
35 #include "llc.h"
36 #include "ethertype.h"
37 #include "oui.h"
38
39 static const struct tok llc_values[] = {
40 { LLCSAP_NULL, "Null" },
41 { LLCSAP_GLOBAL, "Global" },
42 { LLCSAP_8021B_I, "802.1B I" },
43 { LLCSAP_8021B_G, "802.1B G" },
44 { LLCSAP_IP, "IP" },
45 { LLCSAP_SNA, "SNA" },
46 { LLCSAP_PROWAYNM, "ProWay NM" },
47 { LLCSAP_8021D, "STP" },
48 { LLCSAP_RS511, "RS511" },
49 { LLCSAP_ISO8208, "ISO8208" },
50 { LLCSAP_PROWAY, "ProWay" },
51 { LLCSAP_SNAP, "SNAP" },
52 { LLCSAP_IPX, "IPX" },
53 { LLCSAP_NETBEUI, "NetBeui" },
54 { LLCSAP_ISONS, "OSI" },
55 { 0, NULL },
56 };
57
58 static const struct tok llc_cmd_values[] = {
59 { LLC_UI, "ui" },
60 { LLC_TEST, "test" },
61 { LLC_XID, "xid" },
62 { LLC_UA, "ua" },
63 { LLC_DISC, "disc" },
64 { LLC_DM, "dm" },
65 { LLC_SABME, "sabme" },
66 { LLC_FRMR, "frmr" },
67 { 0, NULL }
68 };
69
70 static const struct tok llc_flag_values[] = {
71 { 0, "Command" },
72 { LLC_GSAP, "Response" },
73 { LLC_U_POLL, "Poll" },
74 { LLC_GSAP|LLC_U_POLL, "Final" },
75 { LLC_IS_POLL, "Poll" },
76 { LLC_GSAP|LLC_IS_POLL, "Final" },
77 { 0, NULL }
78 };
79
80
81 static const struct tok llc_ig_flag_values[] = {
82 { 0, "Individual" },
83 { LLC_IG, "Group" },
84 { 0, NULL }
85 };
86
87
88 static const struct tok llc_supervisory_values[] = {
89 { 0, "Receiver Ready" },
90 { 1, "Receiver not Ready" },
91 { 2, "Reject" },
92 { 0, NULL }
93 };
94
95
96 static const struct tok cisco_values[] = {
97 { PID_CISCO_CDP, "CDP" },
98 { PID_CISCO_VTP, "VTP" },
99 { PID_CISCO_DTP, "DTP" },
100 { PID_CISCO_UDLD, "UDLD" },
101 { PID_CISCO_PVST, "PVST" },
102 { PID_CISCO_VLANBRIDGE, "VLAN Bridge" },
103 { 0, NULL }
104 };
105
106 static const struct tok bridged_values[] = {
107 { PID_RFC2684_ETH_FCS, "Ethernet + FCS" },
108 { PID_RFC2684_ETH_NOFCS, "Ethernet w/o FCS" },
109 { PID_RFC2684_802_4_FCS, "802.4 + FCS" },
110 { PID_RFC2684_802_4_NOFCS, "802.4 w/o FCS" },
111 { PID_RFC2684_802_5_FCS, "Token Ring + FCS" },
112 { PID_RFC2684_802_5_NOFCS, "Token Ring w/o FCS" },
113 { PID_RFC2684_FDDI_FCS, "FDDI + FCS" },
114 { PID_RFC2684_FDDI_NOFCS, "FDDI w/o FCS" },
115 { PID_RFC2684_802_6_FCS, "802.6 + FCS" },
116 { PID_RFC2684_802_6_NOFCS, "802.6 w/o FCS" },
117 { PID_RFC2684_BPDU, "BPDU" },
118 { 0, NULL },
119 };
120
121 static const struct tok null_values[] = {
122 { 0, NULL }
123 };
124
125 struct oui_tok {
126 uint32_t oui;
127 const struct tok *tok;
128 };
129
130 static const struct oui_tok oui_to_tok[] = {
131 { OUI_ENCAP_ETHER, ethertype_values },
132 { OUI_CISCO_90, ethertype_values }, /* uses some Ethertype values */
133 { OUI_APPLETALK, ethertype_values }, /* uses some Ethertype values */
134 { OUI_CISCO, cisco_values },
135 { OUI_RFC2684, bridged_values }, /* bridged, RFC 2427 FR or RFC 2864 ATM */
136 { 0, NULL }
137 };
138
139 /*
140 * If we printed information about the payload, returns the length of the LLC
141 * header, plus the length of any SNAP header following it.
142 *
143 * Otherwise (for example, if the packet has unknown SAPs or has a SNAP
144 * header with an unknown OUI/PID combination), returns the *negative*
145 * of that value.
146 */
147 int
llc_print(netdissect_options * ndo,const u_char * p,u_int length,u_int caplen,const struct lladdr_info * src,const struct lladdr_info * dst)148 llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
149 const struct lladdr_info *src, const struct lladdr_info *dst)
150 {
151 uint8_t dsap_field, dsap, ssap_field, ssap;
152 uint16_t control;
153 int hdrlen;
154 int is_u;
155
156 ndo->ndo_protocol = "llc";
157 if (caplen < 3) {
158 nd_print_trunc(ndo);
159 ND_DEFAULTPRINT((const u_char *)p, caplen);
160 return (caplen);
161 }
162 if (length < 3) {
163 nd_print_trunc(ndo);
164 ND_DEFAULTPRINT((const u_char *)p, caplen);
165 return (length);
166 }
167
168 dsap_field = GET_U_1(p);
169 ssap_field = GET_U_1(p + 1);
170
171 /*
172 * OK, what type of LLC frame is this? The length
173 * of the control field depends on that - I frames
174 * have a two-byte control field, and U frames have
175 * a one-byte control field.
176 */
177 control = GET_U_1(p + 2);
178 if ((control & LLC_U_FMT) == LLC_U_FMT) {
179 /*
180 * U frame.
181 */
182 is_u = 1;
183 hdrlen = 3; /* DSAP, SSAP, 1-byte control field */
184 } else {
185 /*
186 * The control field in I and S frames is
187 * 2 bytes...
188 */
189 if (caplen < 4) {
190 nd_print_trunc(ndo);
191 ND_DEFAULTPRINT((const u_char *)p, caplen);
192 return (caplen);
193 }
194 if (length < 4) {
195 nd_print_trunc(ndo);
196 ND_DEFAULTPRINT((const u_char *)p, caplen);
197 return (length);
198 }
199
200 /*
201 * ...and is little-endian.
202 */
203 control = GET_LE_U_2(p + 2);
204 is_u = 0;
205 hdrlen = 4; /* DSAP, SSAP, 2-byte control field */
206 }
207
208 if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
209 /*
210 * This is an Ethernet_802.3 IPX frame; it has an
211 * 802.3 header (i.e., an Ethernet header where the
212 * type/length field is <= MAX_ETHERNET_LENGTH_VAL,
213 * i.e. it's a length field, not a type field), but
214 * has no 802.2 header - the IPX packet starts right
215 * after the Ethernet header, with a signature of two
216 * bytes of 0xFF (which is LLCSAP_GLOBAL).
217 *
218 * (It might also have been an Ethernet_802.3 IPX at
219 * one time, but got bridged onto another network,
220 * such as an 802.11 network; this has appeared in at
221 * least one capture file.)
222 */
223
224 if (ndo->ndo_eflag)
225 ND_PRINT("IPX 802.3: ");
226
227 ipx_print(ndo, p, length);
228 return (0); /* no LLC header */
229 }
230
231 dsap = dsap_field & ~LLC_IG;
232 ssap = ssap_field & ~LLC_GSAP;
233
234 if (ndo->ndo_eflag) {
235 ND_PRINT("LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
236 tok2str(llc_values, "Unknown", dsap),
237 dsap,
238 tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
239 tok2str(llc_values, "Unknown", ssap),
240 ssap,
241 tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP));
242
243 if (is_u) {
244 ND_PRINT(", ctrl 0x%02x: ", control);
245 } else {
246 ND_PRINT(", ctrl 0x%04x: ", control);
247 }
248 }
249
250 /*
251 * Skip LLC header.
252 */
253 p += hdrlen;
254 length -= hdrlen;
255 caplen -= hdrlen;
256
257 if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
258 && control == LLC_UI) {
259 /*
260 * XXX - what *is* the right bridge pad value here?
261 * Does anybody ever bridge one form of LAN traffic
262 * over a networking type that uses 802.2 LLC?
263 */
264 if (!snap_print(ndo, p, length, caplen, src, dst, 2)) {
265 /*
266 * Unknown packet type; tell our caller, by
267 * returning a negative value, so they
268 * can print the raw packet.
269 */
270 return (-(hdrlen + 5)); /* include LLC and SNAP header */
271 } else
272 return (hdrlen + 5); /* include LLC and SNAP header */
273 }
274
275 if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
276 control == LLC_UI) {
277 stp_print(ndo, p, length);
278 return (hdrlen);
279 }
280
281 if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
282 control == LLC_UI) {
283 /*
284 * This is an RFC 948-style IP packet, with
285 * an 802.3 header and an 802.2 LLC header
286 * with the source and destination SAPs being
287 * the IP SAP.
288 */
289 ip_print(ndo, p, length);
290 return (hdrlen);
291 }
292
293 if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
294 control == LLC_UI) {
295 /*
296 * This is an Ethernet_802.2 IPX frame, with an 802.3
297 * header and an 802.2 LLC header with the source and
298 * destination SAPs being the IPX SAP.
299 */
300 if (ndo->ndo_eflag)
301 ND_PRINT("IPX 802.2: ");
302
303 ipx_print(ndo, p, length);
304 return (hdrlen);
305 }
306
307 #ifdef ENABLE_SMB
308 if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
309 && (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
310 /*
311 * we don't actually have a full netbeui parser yet, but the
312 * smb parser can handle many smb-in-netbeui packets, which
313 * is very useful, so we call that
314 *
315 * We don't call it for S frames, however, just I frames
316 * (which are frames that don't have the low-order bit,
317 * LLC_S_FMT, set in the first byte of the control field)
318 * and UI frames (whose control field is just 3, LLC_U_FMT).
319 */
320 netbeui_print(ndo, control, p, length);
321 return (hdrlen);
322 }
323 #endif
324 if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
325 && control == LLC_UI) {
326 isoclns_print(ndo, p, length);
327 return (hdrlen);
328 }
329
330 if (!ndo->ndo_eflag) {
331 if (ssap == dsap) {
332 if (src == NULL || dst == NULL)
333 ND_PRINT("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
334 else
335 ND_PRINT("%s > %s %s ",
336 (src->addr_string)(ndo, src->addr),
337 (dst->addr_string)(ndo, dst->addr),
338 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
339 } else {
340 if (src == NULL || dst == NULL)
341 ND_PRINT("%s > %s ",
342 tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
343 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
344 else
345 ND_PRINT("%s %s > %s %s ",
346 (src->addr_string)(ndo, src->addr),
347 tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
348 (dst->addr_string)(ndo, dst->addr),
349 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
350 }
351 }
352
353 if (is_u) {
354 ND_PRINT("Unnumbered, %s, Flags [%s], length %u",
355 tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
356 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
357 length + hdrlen);
358
359 if ((control & ~LLC_U_POLL) == LLC_XID) {
360 if (length == 0) {
361 /*
362 * XID with no payload.
363 * This could, for example, be an SNA
364 * "short form" XID.
365 */
366 return (hdrlen);
367 }
368 if (caplen < 1) {
369 nd_print_trunc(ndo);
370 if (caplen > 0)
371 ND_DEFAULTPRINT((const u_char *)p, caplen);
372 return (hdrlen);
373 }
374 if (GET_U_1(p) == LLC_XID_FI) {
375 if (caplen < 3 || length < 3) {
376 nd_print_trunc(ndo);
377 if (caplen > 0)
378 ND_DEFAULTPRINT((const u_char *)p, caplen);
379 } else
380 ND_PRINT(": %02x %02x",
381 GET_U_1(p + 1),
382 GET_U_1(p + 2));
383 return (hdrlen);
384 }
385 }
386 } else {
387 if ((control & LLC_S_FMT) == LLC_S_FMT) {
388 ND_PRINT("Supervisory, %s, rcv seq %u, Flags [%s], length %u",
389 tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
390 LLC_IS_NR(control),
391 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
392 length + hdrlen);
393 return (hdrlen); /* no payload to print */
394 } else {
395 ND_PRINT("Information, send seq %u, rcv seq %u, Flags [%s], length %u",
396 LLC_I_NS(control),
397 LLC_IS_NR(control),
398 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
399 length + hdrlen);
400 }
401 }
402 return (-hdrlen);
403 }
404
405 static const struct tok *
oui_to_struct_tok(uint32_t orgcode)406 oui_to_struct_tok(uint32_t orgcode)
407 {
408 const struct tok *tok = null_values;
409 const struct oui_tok *otp;
410
411 for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
412 if (otp->oui == orgcode) {
413 tok = otp->tok;
414 break;
415 }
416 }
417 return (tok);
418 }
419
420 int
snap_print(netdissect_options * ndo,const u_char * p,u_int length,u_int caplen,const struct lladdr_info * src,const struct lladdr_info * dst,u_int bridge_pad)421 snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
422 const struct lladdr_info *src, const struct lladdr_info *dst,
423 u_int bridge_pad)
424 {
425 uint32_t orgcode;
426 u_short et;
427 int ret;
428
429 ndo->ndo_protocol = "snap";
430 ND_TCHECK_5(p);
431 if (caplen < 5 || length < 5)
432 goto trunc;
433 orgcode = GET_BE_U_3(p);
434 et = GET_BE_U_2(p + 3);
435
436 if (ndo->ndo_eflag) {
437 /*
438 * Somebody's already printed the MAC addresses, if there
439 * are any, so just print the SNAP header, not the MAC
440 * addresses.
441 */
442 ND_PRINT("oui %s (0x%06x), %s %s (0x%04x), length %u: ",
443 tok2str(oui_values, "Unknown", orgcode),
444 orgcode,
445 (orgcode == 0x000000 ? "ethertype" : "pid"),
446 tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
447 et, length - 5);
448 }
449 p += 5;
450 length -= 5;
451 caplen -= 5;
452
453 switch (orgcode) {
454 case OUI_ENCAP_ETHER:
455 case OUI_CISCO_90:
456 /*
457 * This is an encapsulated Ethernet packet,
458 * or a packet bridged by some piece of
459 * Cisco hardware; the protocol ID is
460 * an Ethernet protocol type.
461 */
462 ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
463 if (ret)
464 return (ret);
465 break;
466
467 case OUI_APPLETALK:
468 if (et == ETHERTYPE_ATALK) {
469 /*
470 * No, I have no idea why Apple used one
471 * of their own OUIs, rather than
472 * 0x000000, and an Ethernet packet
473 * type, for Appletalk data packets,
474 * but used 0x000000 and an Ethernet
475 * packet type for AARP packets.
476 */
477 ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
478 if (ret)
479 return (ret);
480 }
481 break;
482
483 case OUI_CISCO:
484 switch (et) {
485 case PID_CISCO_CDP:
486 cdp_print(ndo, p, length);
487 return (1);
488 case PID_CISCO_DTP:
489 dtp_print(ndo, p, length);
490 return (1);
491 case PID_CISCO_UDLD:
492 udld_print(ndo, p, length);
493 return (1);
494 case PID_CISCO_VTP:
495 vtp_print(ndo, p, length);
496 return (1);
497 case PID_CISCO_PVST:
498 case PID_CISCO_VLANBRIDGE:
499 stp_print(ndo, p, length);
500 return (1);
501 default:
502 break;
503 }
504 break;
505
506 case OUI_RFC2684:
507 switch (et) {
508
509 case PID_RFC2684_ETH_FCS:
510 case PID_RFC2684_ETH_NOFCS:
511 /*
512 * XXX - remove the last two bytes for
513 * PID_RFC2684_ETH_FCS?
514 */
515 /*
516 * Skip the padding.
517 */
518 ND_TCHECK_LEN(p, bridge_pad);
519 caplen -= bridge_pad;
520 length -= bridge_pad;
521 p += bridge_pad;
522
523 /*
524 * What remains is an Ethernet packet.
525 */
526 ether_print(ndo, p, length, caplen, NULL, NULL);
527 return (1);
528
529 case PID_RFC2684_802_5_FCS:
530 case PID_RFC2684_802_5_NOFCS:
531 /*
532 * XXX - remove the last two bytes for
533 * PID_RFC2684_ETH_FCS?
534 */
535 /*
536 * Skip the padding, but not the Access
537 * Control field.
538 */
539 ND_TCHECK_LEN(p, bridge_pad);
540 caplen -= bridge_pad;
541 length -= bridge_pad;
542 p += bridge_pad;
543
544 /*
545 * What remains is an 802.5 Token Ring
546 * packet.
547 */
548 token_print(ndo, p, length, caplen);
549 return (1);
550
551 case PID_RFC2684_FDDI_FCS:
552 case PID_RFC2684_FDDI_NOFCS:
553 /*
554 * XXX - remove the last two bytes for
555 * PID_RFC2684_ETH_FCS?
556 */
557 /*
558 * Skip the padding.
559 */
560 ND_TCHECK_LEN(p, bridge_pad + 1);
561 caplen -= bridge_pad + 1;
562 length -= bridge_pad + 1;
563 p += bridge_pad + 1;
564
565 /*
566 * What remains is an FDDI packet.
567 */
568 fddi_print(ndo, p, length, caplen);
569 return (1);
570
571 case PID_RFC2684_BPDU:
572 stp_print(ndo, p, length);
573 return (1);
574 }
575 }
576 if (!ndo->ndo_eflag) {
577 /*
578 * Nobody printed the link-layer addresses, so print them, if
579 * we have any.
580 */
581 if (src != NULL && dst != NULL) {
582 ND_PRINT("%s > %s ",
583 (src->addr_string)(ndo, src->addr),
584 (dst->addr_string)(ndo, dst->addr));
585 }
586 /*
587 * Print the SNAP header, but if the OUI is 000000, don't
588 * bother printing it, and report the PID as being an
589 * ethertype.
590 */
591 if (orgcode == 0x000000) {
592 ND_PRINT("SNAP, ethertype %s (0x%04x), length %u: ",
593 tok2str(ethertype_values, "Unknown", et),
594 et, length);
595 } else {
596 ND_PRINT("SNAP, oui %s (0x%06x), pid %s (0x%04x), length %u: ",
597 tok2str(oui_values, "Unknown", orgcode),
598 orgcode,
599 tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
600 et, length);
601 }
602 }
603 return (0);
604
605 trunc:
606 nd_print_trunc(ndo);
607 return (1);
608 }
609