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 #include <sys/cdefs.h>
26 #ifndef lint
27 __RCSID("$NetBSD: print-llc.c,v 1.11 2024/09/02 16:15:31 christos Exp $");
28 #endif
29
30 /* \summary: IEEE 802.2 LLC printer */
31
32 #include <config.h>
33
34 #include "netdissect-stdinc.h"
35
36 #include "netdissect.h"
37 #include "addrtoname.h"
38 #include "extract.h"
39
40 #include "llc.h"
41 #include "ethertype.h"
42 #include "oui.h"
43
44 static const struct tok llc_values[] = {
45 { LLCSAP_NULL, "Null" },
46 { LLCSAP_GLOBAL, "Global" },
47 { LLCSAP_8021B_I, "802.1B I" },
48 { LLCSAP_8021B_G, "802.1B G" },
49 { LLCSAP_IP, "IP" },
50 { LLCSAP_SNA, "SNA" },
51 { LLCSAP_PROWAYNM, "ProWay NM" },
52 { LLCSAP_8021D, "STP" },
53 { LLCSAP_RS511, "RS511" },
54 { LLCSAP_ISO8208, "ISO8208" },
55 { LLCSAP_PROWAY, "ProWay" },
56 { LLCSAP_SNAP, "SNAP" },
57 { LLCSAP_IPX, "IPX" },
58 { LLCSAP_NETBEUI, "NetBeui" },
59 { LLCSAP_ISONS, "OSI" },
60 { 0, NULL },
61 };
62
63 static const struct tok llc_cmd_values[] = {
64 { LLC_UI, "ui" },
65 { LLC_TEST, "test" },
66 { LLC_XID, "xid" },
67 { LLC_UA, "ua" },
68 { LLC_DISC, "disc" },
69 { LLC_DM, "dm" },
70 { LLC_SABME, "sabme" },
71 { LLC_FRMR, "frmr" },
72 { 0, NULL }
73 };
74
75 static const struct tok llc_flag_values[] = {
76 { 0, "Command" },
77 { LLC_GSAP, "Response" },
78 { LLC_U_POLL, "Poll" },
79 { LLC_GSAP|LLC_U_POLL, "Final" },
80 { LLC_IS_POLL, "Poll" },
81 { LLC_GSAP|LLC_IS_POLL, "Final" },
82 { 0, NULL }
83 };
84
85
86 static const struct tok llc_ig_flag_values[] = {
87 { 0, "Individual" },
88 { LLC_IG, "Group" },
89 { 0, NULL }
90 };
91
92
93 static const struct tok llc_supervisory_values[] = {
94 { 0, "Receiver Ready" },
95 { 1, "Receiver not Ready" },
96 { 2, "Reject" },
97 { 0, NULL }
98 };
99
100
101 static const struct tok cisco_values[] = {
102 { PID_CISCO_CDP, "CDP" },
103 { PID_CISCO_VTP, "VTP" },
104 { PID_CISCO_DTP, "DTP" },
105 { PID_CISCO_UDLD, "UDLD" },
106 { PID_CISCO_PVST, "PVST" },
107 { PID_CISCO_VLANBRIDGE, "VLAN Bridge" },
108 { 0, NULL }
109 };
110
111 static const struct tok bridged_values[] = {
112 { PID_RFC2684_ETH_FCS, "Ethernet + FCS" },
113 { PID_RFC2684_ETH_NOFCS, "Ethernet w/o FCS" },
114 { PID_RFC2684_802_4_FCS, "802.4 + FCS" },
115 { PID_RFC2684_802_4_NOFCS, "802.4 w/o FCS" },
116 { PID_RFC2684_802_5_FCS, "Token Ring + FCS" },
117 { PID_RFC2684_802_5_NOFCS, "Token Ring w/o FCS" },
118 { PID_RFC2684_FDDI_FCS, "FDDI + FCS" },
119 { PID_RFC2684_FDDI_NOFCS, "FDDI w/o FCS" },
120 { PID_RFC2684_802_6_FCS, "802.6 + FCS" },
121 { PID_RFC2684_802_6_NOFCS, "802.6 w/o FCS" },
122 { PID_RFC2684_BPDU, "BPDU" },
123 { 0, NULL },
124 };
125
126 static const struct tok null_values[] = {
127 { 0, NULL }
128 };
129
130 struct oui_tok {
131 uint32_t oui;
132 const struct tok *tok;
133 };
134
135 static const struct oui_tok oui_to_tok[] = {
136 { OUI_ENCAP_ETHER, ethertype_values },
137 { OUI_CISCO_90, ethertype_values }, /* uses some Ethertype values */
138 { OUI_APPLETALK, ethertype_values }, /* uses some Ethertype values */
139 { OUI_CISCO, cisco_values },
140 { OUI_RFC2684, bridged_values }, /* bridged, RFC 2427 FR or RFC 2864 ATM */
141 { 0, NULL }
142 };
143
144 /*
145 * If we printed information about the payload, returns the length of the LLC
146 * header, plus the length of any SNAP header following it.
147 *
148 * Otherwise (for example, if the packet has unknown SAPs or has a SNAP
149 * header with an unknown OUI/PID combination), returns the *negative*
150 * of that value.
151 */
152 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)153 llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
154 const struct lladdr_info *src, const struct lladdr_info *dst)
155 {
156 uint8_t dsap_field, dsap, ssap_field, ssap;
157 uint16_t control;
158 int hdrlen;
159 int is_u;
160
161 ndo->ndo_protocol = "llc";
162 if (caplen < 3) {
163 nd_print_trunc(ndo);
164 ND_DEFAULTPRINT((const u_char *)p, caplen);
165 return (caplen);
166 }
167 if (length < 3) {
168 nd_print_trunc(ndo);
169 ND_DEFAULTPRINT((const u_char *)p, caplen);
170 return (length);
171 }
172
173 dsap_field = GET_U_1(p);
174 ssap_field = GET_U_1(p + 1);
175
176 /*
177 * OK, what type of LLC frame is this? The length
178 * of the control field depends on that - I frames
179 * have a two-byte control field, and U frames have
180 * a one-byte control field.
181 */
182 control = GET_U_1(p + 2);
183 if ((control & LLC_U_FMT) == LLC_U_FMT) {
184 /*
185 * U frame.
186 */
187 is_u = 1;
188 hdrlen = 3; /* DSAP, SSAP, 1-byte control field */
189 } else {
190 /*
191 * The control field in I and S frames is
192 * 2 bytes...
193 */
194 if (caplen < 4) {
195 nd_print_trunc(ndo);
196 ND_DEFAULTPRINT((const u_char *)p, caplen);
197 return (caplen);
198 }
199 if (length < 4) {
200 nd_print_trunc(ndo);
201 ND_DEFAULTPRINT((const u_char *)p, caplen);
202 return (length);
203 }
204
205 /*
206 * ...and is little-endian.
207 */
208 control = GET_LE_U_2(p + 2);
209 is_u = 0;
210 hdrlen = 4; /* DSAP, SSAP, 2-byte control field */
211 }
212
213 if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
214 /*
215 * This is an Ethernet_802.3 IPX frame; it has an
216 * 802.3 header (i.e., an Ethernet header where the
217 * type/length field is <= MAX_ETHERNET_LENGTH_VAL,
218 * i.e. it's a length field, not a type field), but
219 * has no 802.2 header - the IPX packet starts right
220 * after the Ethernet header, with a signature of two
221 * bytes of 0xFF (which is LLCSAP_GLOBAL).
222 *
223 * (It might also have been an Ethernet_802.3 IPX at
224 * one time, but got bridged onto another network,
225 * such as an 802.11 network; this has appeared in at
226 * least one capture file.)
227 */
228
229 if (ndo->ndo_eflag)
230 ND_PRINT("IPX 802.3: ");
231
232 ipx_print(ndo, p, length);
233 return (0); /* no LLC header */
234 }
235
236 dsap = dsap_field & ~LLC_IG;
237 ssap = ssap_field & ~LLC_GSAP;
238
239 if (ndo->ndo_eflag) {
240 ND_PRINT("LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
241 tok2str(llc_values, "Unknown", dsap),
242 dsap,
243 tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
244 tok2str(llc_values, "Unknown", ssap),
245 ssap,
246 tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP));
247
248 if (is_u) {
249 ND_PRINT(", ctrl 0x%02x: ", control);
250 } else {
251 ND_PRINT(", ctrl 0x%04x: ", control);
252 }
253 }
254
255 /*
256 * Skip LLC header.
257 */
258 p += hdrlen;
259 length -= hdrlen;
260 caplen -= hdrlen;
261
262 if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
263 && control == LLC_UI) {
264 /*
265 * XXX - what *is* the right bridge pad value here?
266 * Does anybody ever bridge one form of LAN traffic
267 * over a networking type that uses 802.2 LLC?
268 */
269 if (!snap_print(ndo, p, length, caplen, src, dst, 2)) {
270 /*
271 * Unknown packet type; tell our caller, by
272 * returning a negative value, so they
273 * can print the raw packet.
274 */
275 return (-(hdrlen + 5)); /* include LLC and SNAP header */
276 } else
277 return (hdrlen + 5); /* include LLC and SNAP header */
278 }
279
280 if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
281 control == LLC_UI) {
282 stp_print(ndo, p, length);
283 return (hdrlen);
284 }
285
286 if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
287 control == LLC_UI) {
288 /*
289 * This is an RFC 948-style IP packet, with
290 * an 802.3 header and an 802.2 LLC header
291 * with the source and destination SAPs being
292 * the IP SAP.
293 */
294 ip_print(ndo, p, length);
295 return (hdrlen);
296 }
297
298 if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
299 control == LLC_UI) {
300 /*
301 * This is an Ethernet_802.2 IPX frame, with an 802.3
302 * header and an 802.2 LLC header with the source and
303 * destination SAPs being the IPX SAP.
304 */
305 if (ndo->ndo_eflag)
306 ND_PRINT("IPX 802.2: ");
307
308 ipx_print(ndo, p, length);
309 return (hdrlen);
310 }
311
312 #ifdef ENABLE_SMB
313 if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
314 && (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
315 /*
316 * we don't actually have a full netbeui parser yet, but the
317 * smb parser can handle many smb-in-netbeui packets, which
318 * is very useful, so we call that
319 *
320 * We don't call it for S frames, however, just I frames
321 * (which are frames that don't have the low-order bit,
322 * LLC_S_FMT, set in the first byte of the control field)
323 * and UI frames (whose control field is just 3, LLC_U_FMT).
324 */
325 netbeui_print(ndo, control, p, length);
326 return (hdrlen);
327 }
328 #endif
329 if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
330 && control == LLC_UI) {
331 isoclns_print(ndo, p, length);
332 return (hdrlen);
333 }
334
335 if (!ndo->ndo_eflag) {
336 if (ssap == dsap) {
337 if (src == NULL || dst == NULL)
338 ND_PRINT("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
339 else
340 ND_PRINT("%s > %s %s ",
341 (src->addr_string)(ndo, src->addr),
342 (dst->addr_string)(ndo, dst->addr),
343 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
344 } else {
345 if (src == NULL || dst == NULL)
346 ND_PRINT("%s > %s ",
347 tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
348 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
349 else
350 ND_PRINT("%s %s > %s %s ",
351 (src->addr_string)(ndo, src->addr),
352 tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
353 (dst->addr_string)(ndo, dst->addr),
354 tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
355 }
356 }
357
358 if (is_u) {
359 ND_PRINT("Unnumbered, %s, Flags [%s], length %u",
360 tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
361 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
362 length + hdrlen);
363
364 if ((control & ~LLC_U_POLL) == LLC_XID) {
365 if (length == 0) {
366 /*
367 * XID with no payload.
368 * This could, for example, be an SNA
369 * "short form" XID.
370 */
371 return (hdrlen);
372 }
373 if (caplen < 1) {
374 nd_print_trunc(ndo);
375 if (caplen > 0)
376 ND_DEFAULTPRINT((const u_char *)p, caplen);
377 return (hdrlen);
378 }
379 if (GET_U_1(p) == LLC_XID_FI) {
380 if (caplen < 3 || length < 3) {
381 nd_print_trunc(ndo);
382 if (caplen > 0)
383 ND_DEFAULTPRINT((const u_char *)p, caplen);
384 } else
385 ND_PRINT(": %02x %02x",
386 GET_U_1(p + 1),
387 GET_U_1(p + 2));
388 return (hdrlen);
389 }
390 }
391 } else {
392 if ((control & LLC_S_FMT) == LLC_S_FMT) {
393 ND_PRINT("Supervisory, %s, rcv seq %u, Flags [%s], length %u",
394 tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
395 LLC_IS_NR(control),
396 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
397 length + hdrlen);
398 return (hdrlen); /* no payload to print */
399 } else {
400 ND_PRINT("Information, send seq %u, rcv seq %u, Flags [%s], length %u",
401 LLC_I_NS(control),
402 LLC_IS_NR(control),
403 tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
404 length + hdrlen);
405 }
406 }
407 return (-hdrlen);
408 }
409
410 static const struct tok *
oui_to_struct_tok(uint32_t orgcode)411 oui_to_struct_tok(uint32_t orgcode)
412 {
413 const struct tok *tok = null_values;
414 const struct oui_tok *otp;
415
416 for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
417 if (otp->oui == orgcode) {
418 tok = otp->tok;
419 break;
420 }
421 }
422 return (tok);
423 }
424
425 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)426 snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
427 const struct lladdr_info *src, const struct lladdr_info *dst,
428 u_int bridge_pad)
429 {
430 uint32_t orgcode;
431 u_short et;
432 int ret;
433
434 ndo->ndo_protocol = "snap";
435 ND_TCHECK_5(p);
436 if (caplen < 5 || length < 5)
437 goto trunc;
438 orgcode = GET_BE_U_3(p);
439 et = GET_BE_U_2(p + 3);
440
441 if (ndo->ndo_eflag) {
442 /*
443 * Somebody's already printed the MAC addresses, if there
444 * are any, so just print the SNAP header, not the MAC
445 * addresses.
446 */
447 ND_PRINT("oui %s (0x%06x), %s %s (0x%04x), length %u: ",
448 tok2str(oui_values, "Unknown", orgcode),
449 orgcode,
450 (orgcode == 0x000000 ? "ethertype" : "pid"),
451 tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
452 et, length - 5);
453 }
454 p += 5;
455 length -= 5;
456 caplen -= 5;
457
458 switch (orgcode) {
459 case OUI_ENCAP_ETHER:
460 case OUI_CISCO_90:
461 /*
462 * This is an encapsulated Ethernet packet,
463 * or a packet bridged by some piece of
464 * Cisco hardware; the protocol ID is
465 * an Ethernet protocol type.
466 */
467 ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
468 if (ret)
469 return (ret);
470 break;
471
472 case OUI_APPLETALK:
473 if (et == ETHERTYPE_ATALK) {
474 /*
475 * No, I have no idea why Apple used one
476 * of their own OUIs, rather than
477 * 0x000000, and an Ethernet packet
478 * type, for Appletalk data packets,
479 * but used 0x000000 and an Ethernet
480 * packet type for AARP packets.
481 */
482 ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
483 if (ret)
484 return (ret);
485 }
486 break;
487
488 case OUI_CISCO:
489 switch (et) {
490 case PID_CISCO_CDP:
491 cdp_print(ndo, p, length);
492 return (1);
493 case PID_CISCO_DTP:
494 dtp_print(ndo, p, length);
495 return (1);
496 case PID_CISCO_UDLD:
497 udld_print(ndo, p, length);
498 return (1);
499 case PID_CISCO_VTP:
500 vtp_print(ndo, p, length);
501 return (1);
502 case PID_CISCO_PVST:
503 case PID_CISCO_VLANBRIDGE:
504 stp_print(ndo, p, length);
505 return (1);
506 default:
507 break;
508 }
509 break;
510
511 case OUI_RFC2684:
512 switch (et) {
513
514 case PID_RFC2684_ETH_FCS:
515 case PID_RFC2684_ETH_NOFCS:
516 /*
517 * XXX - remove the last two bytes for
518 * PID_RFC2684_ETH_FCS?
519 */
520 /*
521 * Skip the padding.
522 */
523 ND_TCHECK_LEN(p, bridge_pad);
524 caplen -= bridge_pad;
525 length -= bridge_pad;
526 p += bridge_pad;
527
528 /*
529 * What remains is an Ethernet packet.
530 */
531 ether_print(ndo, p, length, caplen, NULL, NULL);
532 return (1);
533
534 case PID_RFC2684_802_5_FCS:
535 case PID_RFC2684_802_5_NOFCS:
536 /*
537 * XXX - remove the last two bytes for
538 * PID_RFC2684_ETH_FCS?
539 */
540 /*
541 * Skip the padding, but not the Access
542 * Control field.
543 */
544 ND_TCHECK_LEN(p, bridge_pad);
545 caplen -= bridge_pad;
546 length -= bridge_pad;
547 p += bridge_pad;
548
549 /*
550 * What remains is an 802.5 Token Ring
551 * packet.
552 */
553 token_print(ndo, p, length, caplen);
554 return (1);
555
556 case PID_RFC2684_FDDI_FCS:
557 case PID_RFC2684_FDDI_NOFCS:
558 /*
559 * XXX - remove the last two bytes for
560 * PID_RFC2684_ETH_FCS?
561 */
562 /*
563 * Skip the padding.
564 */
565 ND_TCHECK_LEN(p, bridge_pad + 1);
566 caplen -= bridge_pad + 1;
567 length -= bridge_pad + 1;
568 p += bridge_pad + 1;
569
570 /*
571 * What remains is an FDDI packet.
572 */
573 fddi_print(ndo, p, length, caplen);
574 return (1);
575
576 case PID_RFC2684_BPDU:
577 stp_print(ndo, p, length);
578 return (1);
579 }
580 }
581 if (!ndo->ndo_eflag) {
582 /*
583 * Nobody printed the link-layer addresses, so print them, if
584 * we have any.
585 */
586 if (src != NULL && dst != NULL) {
587 ND_PRINT("%s > %s ",
588 (src->addr_string)(ndo, src->addr),
589 (dst->addr_string)(ndo, dst->addr));
590 }
591 /*
592 * Print the SNAP header, but if the OUI is 000000, don't
593 * bother printing it, and report the PID as being an
594 * ethertype.
595 */
596 if (orgcode == 0x000000) {
597 ND_PRINT("SNAP, ethertype %s (0x%04x), length %u: ",
598 tok2str(ethertype_values, "Unknown", et),
599 et, length);
600 } else {
601 ND_PRINT("SNAP, oui %s (0x%06x), pid %s (0x%04x), length %u: ",
602 tok2str(oui_values, "Unknown", orgcode),
603 orgcode,
604 tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
605 et, length);
606 }
607 }
608 return (0);
609
610 trunc:
611 nd_print_trunc(ndo);
612 return (1);
613 }
614