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1 /*
2 * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996
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
22 /* \summary: Frame Relay printer */
23
24 #include <config.h>
25
26 #include "netdissect-stdinc.h"
27
28 #include <stdio.h>
29 #include <string.h>
30
31 #include "netdissect.h"
32 #include "addrtoname.h"
33 #include "ethertype.h"
34 #include "llc.h"
35 #include "nlpid.h"
36 #include "extract.h"
37
38 static void frf15_print(netdissect_options *ndo, const u_char *, u_int);
39
40 /*
41 * the frame relay header has a variable length
42 *
43 * the EA bit determines if there is another byte
44 * in the header
45 *
46 * minimum header length is 2 bytes
47 * maximum header length is 4 bytes
48 *
49 * 7 6 5 4 3 2 1 0
50 * +----+----+----+----+----+----+----+----+
51 * | DLCI (6 bits) | CR | EA |
52 * +----+----+----+----+----+----+----+----+
53 * | DLCI (4 bits) |FECN|BECN| DE | EA |
54 * +----+----+----+----+----+----+----+----+
55 * | DLCI (7 bits) | EA |
56 * +----+----+----+----+----+----+----+----+
57 * | DLCI (6 bits) |SDLC| EA |
58 * +----+----+----+----+----+----+----+----+
59 */
60
61 #define FR_EA_BIT 0x01
62
63 #define FR_CR_BIT 0x02000000
64 #define FR_DE_BIT 0x00020000
65 #define FR_BECN_BIT 0x00040000
66 #define FR_FECN_BIT 0x00080000
67 #define FR_SDLC_BIT 0x00000002
68
69
70 static const struct tok fr_header_flag_values[] = {
71 { FR_CR_BIT, "C!" },
72 { FR_DE_BIT, "DE" },
73 { FR_BECN_BIT, "BECN" },
74 { FR_FECN_BIT, "FECN" },
75 { FR_SDLC_BIT, "sdlcore" },
76 { 0, NULL }
77 };
78
79 /* FRF.15 / FRF.16 */
80 #define MFR_B_BIT 0x80
81 #define MFR_E_BIT 0x40
82 #define MFR_C_BIT 0x20
83 #define MFR_BEC_MASK (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
84 #define MFR_CTRL_FRAME (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
85 #define MFR_FRAG_FRAME (MFR_B_BIT | MFR_E_BIT )
86
87 static const struct tok frf_flag_values[] = {
88 { MFR_B_BIT, "Begin" },
89 { MFR_E_BIT, "End" },
90 { MFR_C_BIT, "Control" },
91 { 0, NULL }
92 };
93
94 /* Finds out Q.922 address length, DLCI and flags. Returns 1 on success,
95 * 0 on invalid address, -1 on truncated packet
96 * save the flags dep. on address length
97 */
98 static int parse_q922_header(netdissect_options *ndo,
99 const u_char *p, u_int *dlci,
100 u_int *addr_len, uint32_t *flags, u_int length)
101 {
102 if (!ND_TTEST_1(p) || length < 1)
103 return -1;
104 if ((GET_U_1(p) & FR_EA_BIT))
105 return 0;
106
107 if (!ND_TTEST_1(p + 1) || length < 2)
108 return -1;
109 *addr_len = 2;
110 *dlci = ((GET_U_1(p) & 0xFC) << 2) | ((GET_U_1(p + 1) & 0xF0) >> 4);
111
112 *flags = ((GET_U_1(p) & 0x02) << 24) | /* CR flag */
113 ((GET_U_1(p + 1) & 0x0e) << 16); /* FECN,BECN,DE flags */
114
115 if (GET_U_1(p + 1) & FR_EA_BIT)
116 return 1; /* 2-byte Q.922 address */
117
118 p += 2;
119 length -= 2;
120 if (!ND_TTEST_1(p) || length < 1)
121 return -1;
122 (*addr_len)++; /* 3- or 4-byte Q.922 address */
123 if ((GET_U_1(p) & FR_EA_BIT) == 0) {
124 *dlci = (*dlci << 7) | (GET_U_1(p) >> 1);
125 (*addr_len)++; /* 4-byte Q.922 address */
126 p++;
127 length--;
128 }
129
130 if (!ND_TTEST_1(p) || length < 1)
131 return -1;
132 if ((GET_U_1(p) & FR_EA_BIT) == 0)
133 return 0; /* more than 4 bytes of Q.922 address? */
134
135 *flags = *flags | (GET_U_1(p) & 0x02); /* SDLC flag */
136
137 *dlci = (*dlci << 6) | (GET_U_1(p) >> 2);
138
139 return 1;
140 }
141
142 const char *
143 q922_string(netdissect_options *ndo, const u_char *p, u_int length)
144 {
145
146 static u_int dlci, addr_len;
147 static uint32_t flags;
148 static char buffer[sizeof("parse_q922_header() returned XXXXXXXXXXX")];
149 int ret;
150 memset(buffer, 0, sizeof(buffer));
151
152 ret = parse_q922_header(ndo, p, &dlci, &addr_len, &flags, length);
153 if (ret == 1) {
154 snprintf(buffer, sizeof(buffer), "DLCI %u", dlci);
155 return buffer;
156 } else if (ret == 0) {
157 return "<Invalid DLCI>";
158 } else if (ret == -1) {
159 return "<Truncated>";
160 } else {
161 snprintf(buffer, sizeof(buffer), "parse_q922_header() returned %d", ret);
162 return buffer;
163 }
164 }
165
166
167 /* Frame Relay packet structure, with flags and CRC removed
168
169 +---------------------------+
170 | Q.922 Address* |
171 +-- --+
172 | |
173 +---------------------------+
174 | Control (UI = 0x03) |
175 +---------------------------+
176 | Optional Pad (0x00) |
177 +---------------------------+
178 | NLPID |
179 +---------------------------+
180 | . |
181 | . |
182 | . |
183 | Data |
184 | . |
185 | . |
186 +---------------------------+
187
188 * Q.922 addresses, as presently defined, are two octets and
189 contain a 10-bit DLCI. In some networks Q.922 addresses
190 may optionally be increased to three or four octets.
191 */
192
193 static void
194 fr_hdr_print(netdissect_options *ndo, int length, u_int addr_len,
195 u_int dlci, uint32_t flags, uint16_t nlpid)
196 {
197 if (ndo->ndo_qflag) {
198 ND_PRINT("Q.922, DLCI %u, length %u: ",
199 dlci,
200 length);
201 } else {
202 if (nlpid <= 0xff) /* if its smaller than 256 then its a NLPID */
203 ND_PRINT("Q.922, hdr-len %u, DLCI %u, Flags [%s], NLPID %s (0x%02x), length %u: ",
204 addr_len,
205 dlci,
206 bittok2str(fr_header_flag_values, "none", flags),
207 tok2str(nlpid_values,"unknown", nlpid),
208 nlpid,
209 length);
210 else /* must be an ethertype */
211 ND_PRINT("Q.922, hdr-len %u, DLCI %u, Flags [%s], cisco-ethertype %s (0x%04x), length %u: ",
212 addr_len,
213 dlci,
214 bittok2str(fr_header_flag_values, "none", flags),
215 tok2str(ethertype_values, "unknown", nlpid),
216 nlpid,
217 length);
218 }
219 }
220
221 /* Frame Relay */
222 void
223 fr_if_print(netdissect_options *ndo,
224 const struct pcap_pkthdr *h, const u_char *p)
225 {
226 u_int length = h->len;
227 u_int caplen = h->caplen;
228
229 ndo->ndo_protocol = "fr";
230 if (caplen < 4) { /* minimum frame header length */
231 nd_print_trunc(ndo);
232 ndo->ndo_ll_hdr_len += caplen;
233 return;
234 }
235
236 ndo->ndo_ll_hdr_len += fr_print(ndo, p, length);
237 }
238
239 u_int
240 fr_print(netdissect_options *ndo,
241 const u_char *p, u_int length)
242 {
243 int ret;
244 uint16_t extracted_ethertype;
245 u_int dlci;
246 u_int addr_len;
247 uint16_t nlpid;
248 u_int hdr_len;
249 uint32_t flags;
250
251 ndo->ndo_protocol = "fr";
252 ret = parse_q922_header(ndo, p, &dlci, &addr_len, &flags, length);
253 if (ret == -1)
254 goto trunc;
255 if (ret == 0) {
256 ND_PRINT("Q.922, invalid address");
257 return 0;
258 }
259
260 ND_TCHECK_1(p + addr_len);
261 if (length < addr_len + 1)
262 goto trunc;
263
264 if (GET_U_1(p + addr_len) != LLC_UI && dlci != 0) {
265 /*
266 * Let's figure out if we have Cisco-style encapsulation,
267 * with an Ethernet type (Cisco HDLC type?) following the
268 * address.
269 */
270 if (!ND_TTEST_2(p + addr_len) || length < addr_len + 2) {
271 /* no Ethertype */
272 ND_PRINT("UI %02x! ", GET_U_1(p + addr_len));
273 } else {
274 extracted_ethertype = GET_BE_U_2(p + addr_len);
275
276 if (ndo->ndo_eflag)
277 fr_hdr_print(ndo, length, addr_len, dlci,
278 flags, extracted_ethertype);
279
280 if (ethertype_print(ndo, extracted_ethertype,
281 p+addr_len+ETHERTYPE_LEN,
282 length-addr_len-ETHERTYPE_LEN,
283 ND_BYTES_AVAILABLE_AFTER(p)-addr_len-ETHERTYPE_LEN,
284 NULL, NULL) == 0)
285 /* ether_type not known, probably it wasn't one */
286 ND_PRINT("UI %02x! ", GET_U_1(p + addr_len));
287 else
288 return addr_len + 2;
289 }
290 }
291
292 ND_TCHECK_1(p + addr_len + 1);
293 if (length < addr_len + 2)
294 goto trunc;
295
296 if (GET_U_1(p + addr_len + 1) == 0) {
297 /*
298 * Assume a pad byte after the control (UI) byte.
299 * A pad byte should only be used with 3-byte Q.922.
300 */
301 if (addr_len != 3)
302 ND_PRINT("Pad! ");
303 hdr_len = addr_len + 1 /* UI */ + 1 /* pad */ + 1 /* NLPID */;
304 } else {
305 /*
306 * Not a pad byte.
307 * A pad byte should be used with 3-byte Q.922.
308 */
309 if (addr_len == 3)
310 ND_PRINT("No pad! ");
311 hdr_len = addr_len + 1 /* UI */ + 1 /* NLPID */;
312 }
313
314 ND_TCHECK_1(p + hdr_len - 1);
315 if (length < hdr_len)
316 goto trunc;
317 nlpid = GET_U_1(p + hdr_len - 1);
318
319 if (ndo->ndo_eflag)
320 fr_hdr_print(ndo, length, addr_len, dlci, flags, nlpid);
321 p += hdr_len;
322 length -= hdr_len;
323
324 switch (nlpid) {
325 case NLPID_IP:
326 ip_print(ndo, p, length);
327 break;
328
329 case NLPID_IP6:
330 ip6_print(ndo, p, length);
331 break;
332
333 case NLPID_CLNP:
334 case NLPID_ESIS:
335 case NLPID_ISIS:
336 isoclns_print(ndo, p - 1, length + 1); /* OSI printers need the NLPID field */
337 break;
338
339 case NLPID_SNAP:
340 if (snap_print(ndo, p, length, ND_BYTES_AVAILABLE_AFTER(p), NULL, NULL, 0) == 0) {
341 /* ether_type not known, print raw packet */
342 if (!ndo->ndo_eflag)
343 fr_hdr_print(ndo, length + hdr_len, hdr_len,
344 dlci, flags, nlpid);
345 if (!ndo->ndo_suppress_default_print)
346 ND_DEFAULTPRINT(p - hdr_len, length + hdr_len);
347 }
348 break;
349
350 case NLPID_Q933:
351 q933_print(ndo, p, length);
352 break;
353
354 case NLPID_MFR:
355 frf15_print(ndo, p, length);
356 break;
357
358 case NLPID_PPP:
359 ppp_print(ndo, p, length);
360 break;
361
362 default:
363 if (!ndo->ndo_eflag)
364 fr_hdr_print(ndo, length + hdr_len, addr_len,
365 dlci, flags, nlpid);
366 if (!ndo->ndo_xflag)
367 ND_DEFAULTPRINT(p, length);
368 }
369
370 return hdr_len;
371
372 trunc:
373 nd_print_trunc(ndo);
374 return 0;
375
376 }
377
378 /* Multi Link Frame Relay (FRF.16) */
379 void
380 mfr_if_print(netdissect_options *ndo,
381 const struct pcap_pkthdr *h, const u_char *p)
382 {
383 u_int length = h->len;
384 u_int caplen = h->caplen;
385
386 ndo->ndo_protocol = "mfr";
387 if (caplen < 2) { /* minimum frame header length */
388 nd_print_trunc(ndo);
389 ndo->ndo_ll_hdr_len += caplen;
390 return;
391 }
392
393 ndo->ndo_ll_hdr_len += mfr_print(ndo, p, length);
394 }
395
396
397 #define MFR_CTRL_MSG_ADD_LINK 1
398 #define MFR_CTRL_MSG_ADD_LINK_ACK 2
399 #define MFR_CTRL_MSG_ADD_LINK_REJ 3
400 #define MFR_CTRL_MSG_HELLO 4
401 #define MFR_CTRL_MSG_HELLO_ACK 5
402 #define MFR_CTRL_MSG_REMOVE_LINK 6
403 #define MFR_CTRL_MSG_REMOVE_LINK_ACK 7
404
405 static const struct tok mfr_ctrl_msg_values[] = {
406 { MFR_CTRL_MSG_ADD_LINK, "Add Link" },
407 { MFR_CTRL_MSG_ADD_LINK_ACK, "Add Link ACK" },
408 { MFR_CTRL_MSG_ADD_LINK_REJ, "Add Link Reject" },
409 { MFR_CTRL_MSG_HELLO, "Hello" },
410 { MFR_CTRL_MSG_HELLO_ACK, "Hello ACK" },
411 { MFR_CTRL_MSG_REMOVE_LINK, "Remove Link" },
412 { MFR_CTRL_MSG_REMOVE_LINK_ACK, "Remove Link ACK" },
413 { 0, NULL }
414 };
415
416 #define MFR_CTRL_IE_BUNDLE_ID 1
417 #define MFR_CTRL_IE_LINK_ID 2
418 #define MFR_CTRL_IE_MAGIC_NUM 3
419 #define MFR_CTRL_IE_TIMESTAMP 5
420 #define MFR_CTRL_IE_VENDOR_EXT 6
421 #define MFR_CTRL_IE_CAUSE 7
422
423 static const struct tok mfr_ctrl_ie_values[] = {
424 { MFR_CTRL_IE_BUNDLE_ID, "Bundle ID"},
425 { MFR_CTRL_IE_LINK_ID, "Link ID"},
426 { MFR_CTRL_IE_MAGIC_NUM, "Magic Number"},
427 { MFR_CTRL_IE_TIMESTAMP, "Timestamp"},
428 { MFR_CTRL_IE_VENDOR_EXT, "Vendor Extension"},
429 { MFR_CTRL_IE_CAUSE, "Cause"},
430 { 0, NULL }
431 };
432
433 #define MFR_ID_STRING_MAXLEN 50
434
435 struct ie_tlv_header_t {
436 uint8_t ie_type;
437 uint8_t ie_len;
438 };
439
440 u_int
441 mfr_print(netdissect_options *ndo,
442 const u_char *p, u_int length)
443 {
444 u_int tlen,hdr_len = 0;
445 uint16_t sequence_num;
446 uint8_t ie_type,ie_len;
447 const uint8_t *tptr;
448
449
450 /*
451 * FRF.16 Link Integrity Control Frame
452 *
453 * 7 6 5 4 3 2 1 0
454 * +----+----+----+----+----+----+----+----+
455 * | B | E | C=1| 0 0 0 0 | EA |
456 * +----+----+----+----+----+----+----+----+
457 * | 0 0 0 0 0 0 0 0 |
458 * +----+----+----+----+----+----+----+----+
459 * | message type |
460 * +----+----+----+----+----+----+----+----+
461 */
462
463 ndo->ndo_protocol = "mfr";
464
465 if (length < 4) { /* minimum frame header length */
466 ND_PRINT("[length %u < 4]", length);
467 nd_print_invalid(ndo);
468 return length;
469 }
470 ND_TCHECK_4(p);
471
472 if ((GET_U_1(p) & MFR_BEC_MASK) == MFR_CTRL_FRAME && GET_U_1(p + 1) == 0) {
473 ND_PRINT("FRF.16 Control, Flags [%s], %s, length %u",
474 bittok2str(frf_flag_values,"none",(GET_U_1(p) & MFR_BEC_MASK)),
475 tok2str(mfr_ctrl_msg_values,"Unknown Message (0x%02x)",GET_U_1(p + 2)),
476 length);
477 tptr = p + 3;
478 tlen = length -3;
479 hdr_len = 3;
480
481 if (!ndo->ndo_vflag)
482 return hdr_len;
483
484 while (tlen>sizeof(struct ie_tlv_header_t)) {
485 ND_TCHECK_LEN(tptr, sizeof(struct ie_tlv_header_t));
486 ie_type=GET_U_1(tptr);
487 ie_len=GET_U_1(tptr + 1);
488
489 ND_PRINT("\n\tIE %s (%u), length %u: ",
490 tok2str(mfr_ctrl_ie_values,"Unknown",ie_type),
491 ie_type,
492 ie_len);
493
494 /* infinite loop check */
495 if (ie_type == 0 || ie_len <= sizeof(struct ie_tlv_header_t))
496 return hdr_len;
497
498 ND_TCHECK_LEN(tptr, ie_len);
499 tptr+=sizeof(struct ie_tlv_header_t);
500 /* tlv len includes header */
501 ie_len-=sizeof(struct ie_tlv_header_t);
502 tlen-=sizeof(struct ie_tlv_header_t);
503
504 switch (ie_type) {
505
506 case MFR_CTRL_IE_MAGIC_NUM:
507 /* FRF.16.1 Section 3.4.3 Magic Number Information Element */
508 if (ie_len != 4) {
509 ND_PRINT("[IE data length %d != 4]", ie_len);
510 nd_print_invalid(ndo);
511 break;
512 }
513 ND_PRINT("0x%08x", GET_BE_U_4(tptr));
514 break;
515
516 case MFR_CTRL_IE_BUNDLE_ID: /* same message format */
517 case MFR_CTRL_IE_LINK_ID:
518 nd_printjnp(ndo, tptr, ND_MIN(ie_len, MFR_ID_STRING_MAXLEN));
519 break;
520
521 case MFR_CTRL_IE_TIMESTAMP:
522 /*
523 * FRF.16.1 Section 3.4.4 Timestamp Information Element
524 *
525 * The maximum length is 14 octets. Format is implementation
526 * specific.
527 */
528 if (ie_len > 14) {
529 ND_PRINT("[Timestamp IE length %d > 14]", ie_len);
530 nd_print_invalid(ndo);
531 break;
532 }
533 /* fall through and hexdump */
534 ND_FALL_THROUGH;
535
536 /*
537 * FIXME those are the defined IEs that lack a decoder
538 * you are welcome to contribute code ;-)
539 */
540
541 case MFR_CTRL_IE_VENDOR_EXT:
542 case MFR_CTRL_IE_CAUSE:
543
544 default:
545 if (ndo->ndo_vflag <= 1)
546 print_unknown_data(ndo, tptr, "\n\t ", ie_len);
547 break;
548 }
549
550 /* do we want to see a hexdump of the IE ? */
551 if (ndo->ndo_vflag > 1 )
552 print_unknown_data(ndo, tptr, "\n\t ", ie_len);
553
554 tlen-=ie_len;
555 tptr+=ie_len;
556 }
557 return hdr_len;
558 }
559 /*
560 * FRF.16 Fragmentation Frame
561 *
562 * 7 6 5 4 3 2 1 0
563 * +----+----+----+----+----+----+----+----+
564 * | B | E | C=0|seq. (high 4 bits) | EA |
565 * +----+----+----+----+----+----+----+----+
566 * | sequence (low 8 bits) |
567 * +----+----+----+----+----+----+----+----+
568 * | DLCI (6 bits) | CR | EA |
569 * +----+----+----+----+----+----+----+----+
570 * | DLCI (4 bits) |FECN|BECN| DE | EA |
571 * +----+----+----+----+----+----+----+----+
572 */
573
574 sequence_num = (GET_U_1(p)&0x1e)<<7 | GET_U_1(p + 1);
575 /* whole packet or first fragment ? */
576 if ((GET_U_1(p) & MFR_BEC_MASK) == MFR_FRAG_FRAME ||
577 (GET_U_1(p) & MFR_BEC_MASK) == MFR_B_BIT) {
578 ND_PRINT("FRF.16 Frag, seq %u, Flags [%s], ",
579 sequence_num,
580 bittok2str(frf_flag_values,"none",(GET_U_1(p) & MFR_BEC_MASK)));
581 hdr_len = 2;
582 fr_print(ndo, p+hdr_len,length-hdr_len);
583 return hdr_len;
584 }
585
586 /* must be a middle or the last fragment */
587 ND_PRINT("FRF.16 Frag, seq %u, Flags [%s]",
588 sequence_num,
589 bittok2str(frf_flag_values,"none",(GET_U_1(p) & MFR_BEC_MASK)));
590 print_unknown_data(ndo, p, "\n\t", length);
591
592 return hdr_len;
593
594 trunc:
595 nd_print_trunc(ndo);
596 return length;
597 }
598
599 /* an NLPID of 0xb1 indicates a 2-byte
600 * FRF.15 header
601 *
602 * 7 6 5 4 3 2 1 0
603 * +----+----+----+----+----+----+----+----+
604 * ~ Q.922 header ~
605 * +----+----+----+----+----+----+----+----+
606 * | NLPID (8 bits) | NLPID=0xb1
607 * +----+----+----+----+----+----+----+----+
608 * | B | E | C |seq. (high 4 bits) | R |
609 * +----+----+----+----+----+----+----+----+
610 * | sequence (low 8 bits) |
611 * +----+----+----+----+----+----+----+----+
612 */
613
614 #define FR_FRF15_FRAGTYPE 0x01
615
616 static void
617 frf15_print(netdissect_options *ndo,
618 const u_char *p, u_int length)
619 {
620 uint16_t sequence_num, flags;
621
622 if (length < 2)
623 goto trunc;
624
625 flags = GET_U_1(p)&MFR_BEC_MASK;
626 sequence_num = (GET_U_1(p)&0x1e)<<7 | GET_U_1(p + 1);
627
628 ND_PRINT("FRF.15, seq 0x%03x, Flags [%s],%s Fragmentation, length %u",
629 sequence_num,
630 bittok2str(frf_flag_values,"none",flags),
631 GET_U_1(p)&FR_FRF15_FRAGTYPE ? "Interface" : "End-to-End",
632 length);
633
634 /* TODO:
635 * depending on all permutations of the B, E and C bit
636 * dig as deep as we can - e.g. on the first (B) fragment
637 * there is enough payload to print the IP header
638 * on non (B) fragments it depends if the fragmentation
639 * model is end-to-end or interface based whether we want to print
640 * another Q.922 header
641 */
642 return;
643
644 trunc:
645 nd_print_trunc(ndo);
646 }
647
648 /*
649 * Q.933 decoding portion for framerelay specific.
650 */
651
652 /* Q.933 packet format
653 Format of Other Protocols
654 using Q.933 NLPID
655 +-------------------------------+
656 | Q.922 Address |
657 +---------------+---------------+
658 |Control 0x03 | NLPID 0x08 |
659 +---------------+---------------+
660 | L2 Protocol ID |
661 | octet 1 | octet 2 |
662 +-------------------------------+
663 | L3 Protocol ID |
664 | octet 2 | octet 2 |
665 +-------------------------------+
666 | Protocol Data |
667 +-------------------------------+
668 | FCS |
669 +-------------------------------+
670 */
671
672 /* L2 (Octet 1)- Call Reference Usually is 0x0 */
673
674 /*
675 * L2 (Octet 2)- Message Types definition 1 byte long.
676 */
677 /* Call Establish */
678 #define MSG_TYPE_ESC_TO_NATIONAL 0x00
679 #define MSG_TYPE_ALERT 0x01
680 #define MSG_TYPE_CALL_PROCEEDING 0x02
681 #define MSG_TYPE_CONNECT 0x07
682 #define MSG_TYPE_CONNECT_ACK 0x0F
683 #define MSG_TYPE_PROGRESS 0x03
684 #define MSG_TYPE_SETUP 0x05
685 /* Call Clear */
686 #define MSG_TYPE_DISCONNECT 0x45
687 #define MSG_TYPE_RELEASE 0x4D
688 #define MSG_TYPE_RELEASE_COMPLETE 0x5A
689 #define MSG_TYPE_RESTART 0x46
690 #define MSG_TYPE_RESTART_ACK 0x4E
691 /* Status */
692 #define MSG_TYPE_STATUS 0x7D
693 #define MSG_TYPE_STATUS_ENQ 0x75
694
695 static const struct tok fr_q933_msg_values[] = {
696 { MSG_TYPE_ESC_TO_NATIONAL, "ESC to National" },
697 { MSG_TYPE_ALERT, "Alert" },
698 { MSG_TYPE_CALL_PROCEEDING, "Call proceeding" },
699 { MSG_TYPE_CONNECT, "Connect" },
700 { MSG_TYPE_CONNECT_ACK, "Connect ACK" },
701 { MSG_TYPE_PROGRESS, "Progress" },
702 { MSG_TYPE_SETUP, "Setup" },
703 { MSG_TYPE_DISCONNECT, "Disconnect" },
704 { MSG_TYPE_RELEASE, "Release" },
705 { MSG_TYPE_RELEASE_COMPLETE, "Release Complete" },
706 { MSG_TYPE_RESTART, "Restart" },
707 { MSG_TYPE_RESTART_ACK, "Restart ACK" },
708 { MSG_TYPE_STATUS, "Status Reply" },
709 { MSG_TYPE_STATUS_ENQ, "Status Enquiry" },
710 { 0, NULL }
711 };
712
713 #define IE_IS_SINGLE_OCTET(iecode) ((iecode) & 0x80)
714 #define IE_IS_SHIFT(iecode) (((iecode) & 0xF0) == 0x90)
715 #define IE_SHIFT_IS_NON_LOCKING(iecode) ((iecode) & 0x08)
716 #define IE_SHIFT_IS_LOCKING(iecode) (!(IE_SHIFT_IS_NON_LOCKING(iecode)))
717 #define IE_SHIFT_CODESET(iecode) ((iecode) & 0x07)
718
719 #define FR_LMI_ANSI_REPORT_TYPE_IE 0x01
720 #define FR_LMI_ANSI_LINK_VERIFY_IE_91 0x19 /* details? */
721 #define FR_LMI_ANSI_LINK_VERIFY_IE 0x03
722 #define FR_LMI_ANSI_PVC_STATUS_IE 0x07
723
724 #define FR_LMI_CCITT_REPORT_TYPE_IE 0x51
725 #define FR_LMI_CCITT_LINK_VERIFY_IE 0x53
726 #define FR_LMI_CCITT_PVC_STATUS_IE 0x57
727
728 static const struct tok fr_q933_ie_values_codeset_0_5[] = {
729 { FR_LMI_ANSI_REPORT_TYPE_IE, "ANSI Report Type" },
730 { FR_LMI_ANSI_LINK_VERIFY_IE_91, "ANSI Link Verify" },
731 { FR_LMI_ANSI_LINK_VERIFY_IE, "ANSI Link Verify" },
732 { FR_LMI_ANSI_PVC_STATUS_IE, "ANSI PVC Status" },
733 { FR_LMI_CCITT_REPORT_TYPE_IE, "CCITT Report Type" },
734 { FR_LMI_CCITT_LINK_VERIFY_IE, "CCITT Link Verify" },
735 { FR_LMI_CCITT_PVC_STATUS_IE, "CCITT PVC Status" },
736 { 0, NULL }
737 };
738
739 #define FR_LMI_REPORT_TYPE_IE_FULL_STATUS 0
740 #define FR_LMI_REPORT_TYPE_IE_LINK_VERIFY 1
741 #define FR_LMI_REPORT_TYPE_IE_ASYNC_PVC 2
742
743 static const struct tok fr_lmi_report_type_ie_values[] = {
744 { FR_LMI_REPORT_TYPE_IE_FULL_STATUS, "Full Status" },
745 { FR_LMI_REPORT_TYPE_IE_LINK_VERIFY, "Link verify" },
746 { FR_LMI_REPORT_TYPE_IE_ASYNC_PVC, "Async PVC Status" },
747 { 0, NULL }
748 };
749
750 /* array of 16 codesets - currently we only support codepage 0 and 5 */
751 static const struct tok *fr_q933_ie_codesets[] = {
752 fr_q933_ie_values_codeset_0_5,
753 NULL,
754 NULL,
755 NULL,
756 NULL,
757 fr_q933_ie_values_codeset_0_5,
758 NULL,
759 NULL,
760 NULL,
761 NULL,
762 NULL,
763 NULL,
764 NULL,
765 NULL,
766 NULL,
767 NULL
768 };
769
770 static int fr_q933_print_ie_codeset_0_5(netdissect_options *ndo, u_int iecode,
771 u_int ielength, const u_char *p);
772
773 typedef int (*codeset_pr_func_t)(netdissect_options *, u_int iecode,
774 u_int ielength, const u_char *p);
775
776 /* array of 16 codesets - currently we only support codepage 0 and 5 */
777 static const codeset_pr_func_t fr_q933_print_ie_codeset[] = {
778 fr_q933_print_ie_codeset_0_5,
779 NULL,
780 NULL,
781 NULL,
782 NULL,
783 fr_q933_print_ie_codeset_0_5,
784 NULL,
785 NULL,
786 NULL,
787 NULL,
788 NULL,
789 NULL,
790 NULL,
791 NULL,
792 NULL,
793 NULL
794 };
795
796 /*
797 * ITU-T Q.933.
798 *
799 * p points to octet 2, the octet containing the length of the
800 * call reference value, so p[n] is octet n+2 ("octet X" is as
801 * used in Q.931/Q.933).
802 *
803 * XXX - actually used both for Q.931 and Q.933.
804 */
805 void
806 q933_print(netdissect_options *ndo,
807 const u_char *p, u_int length)
808 {
809 u_int olen;
810 u_int call_ref_length, i;
811 uint8_t call_ref[15]; /* maximum length - length field is 4 bits */
812 u_int msgtype;
813 u_int iecode;
814 u_int ielength;
815 u_int codeset = 0;
816 u_int is_ansi = 0;
817 u_int ie_is_known;
818 u_int non_locking_shift;
819 u_int unshift_codeset;
820
821 ndo->ndo_protocol = "q.933";
822 ND_PRINT("%s", ndo->ndo_eflag ? "" : "Q.933");
823
824 if (length == 0 || !ND_TTEST_1(p)) {
825 if (!ndo->ndo_eflag)
826 ND_PRINT(", ");
827 ND_PRINT("length %u", length);
828 goto trunc;
829 }
830
831 /*
832 * Get the length of the call reference value.
833 */
834 olen = length; /* preserve the original length for display */
835 call_ref_length = GET_U_1(p) & 0x0f;
836 p++;
837 length--;
838
839 /*
840 * Get the call reference value.
841 */
842 for (i = 0; i < call_ref_length; i++) {
843 if (length == 0 || !ND_TTEST_1(p)) {
844 if (!ndo->ndo_eflag)
845 ND_PRINT(", ");
846 ND_PRINT("length %u", olen);
847 goto trunc;
848 }
849 call_ref[i] = GET_U_1(p);
850 p++;
851 length--;
852 }
853
854 /*
855 * Get the message type.
856 */
857 if (length == 0 || !ND_TTEST_1(p)) {
858 if (!ndo->ndo_eflag)
859 ND_PRINT(", ");
860 ND_PRINT("length %u", olen);
861 goto trunc;
862 }
863 msgtype = GET_U_1(p);
864 p++;
865 length--;
866
867 /*
868 * Peek ahead to see if we start with a shift.
869 */
870 non_locking_shift = 0;
871 unshift_codeset = codeset;
872 if (length != 0) {
873 if (!ND_TTEST_1(p)) {
874 if (!ndo->ndo_eflag)
875 ND_PRINT(", ");
876 ND_PRINT("length %u", olen);
877 goto trunc;
878 }
879 iecode = GET_U_1(p);
880 if (IE_IS_SHIFT(iecode)) {
881 /*
882 * It's a shift. Skip over it.
883 */
884 p++;
885 length--;
886
887 /*
888 * Get the codeset.
889 */
890 codeset = IE_SHIFT_CODESET(iecode);
891
892 /*
893 * If it's a locking shift to codeset 5,
894 * mark this as ANSI. (XXX - 5 is actually
895 * for national variants in general, not
896 * the US variant in particular, but maybe
897 * this is more American exceptionalism. :-))
898 */
899 if (IE_SHIFT_IS_LOCKING(iecode)) {
900 /*
901 * It's a locking shift.
902 */
903 if (codeset == 5) {
904 /*
905 * It's a locking shift to
906 * codeset 5, so this is
907 * T1.617 Annex D.
908 */
909 is_ansi = 1;
910 }
911 } else {
912 /*
913 * It's a non-locking shift.
914 * Remember the current codeset, so we
915 * can revert to it after the next IE.
916 */
917 non_locking_shift = 1;
918 unshift_codeset = 0;
919 }
920 }
921 }
922
923 /* printing out header part */
924 if (!ndo->ndo_eflag)
925 ND_PRINT(", ");
926 ND_PRINT("%s, codeset %u", is_ansi ? "ANSI" : "CCITT", codeset);
927
928 if (call_ref_length != 0) {
929 if (call_ref_length > 1 || GET_U_1(p) != 0) {
930 /*
931 * Not a dummy call reference.
932 */
933 ND_PRINT(", Call Ref: 0x");
934 for (i = 0; i < call_ref_length; i++)
935 ND_PRINT("%02x", call_ref[i]);
936 }
937 }
938 if (ndo->ndo_vflag) {
939 ND_PRINT(", %s (0x%02x), length %u",
940 tok2str(fr_q933_msg_values,
941 "unknown message", msgtype),
942 msgtype,
943 olen);
944 } else {
945 ND_PRINT(", %s",
946 tok2str(fr_q933_msg_values,
947 "unknown message 0x%02x", msgtype));
948 }
949
950 /* Loop through the rest of the IEs */
951 while (length != 0) {
952 /*
953 * What's the state of any non-locking shifts?
954 */
955 if (non_locking_shift == 1) {
956 /*
957 * There's a non-locking shift in effect for
958 * this IE. Count it, so we reset the codeset
959 * before the next IE.
960 */
961 non_locking_shift = 2;
962 } else if (non_locking_shift == 2) {
963 /*
964 * Unshift.
965 */
966 codeset = unshift_codeset;
967 non_locking_shift = 0;
968 }
969
970 /*
971 * Get the first octet of the IE.
972 */
973 if (!ND_TTEST_1(p)) {
974 if (!ndo->ndo_vflag) {
975 ND_PRINT(", length %u", olen);
976 }
977 goto trunc;
978 }
979 iecode = GET_U_1(p);
980 p++;
981 length--;
982
983 /* Single-octet IE? */
984 if (IE_IS_SINGLE_OCTET(iecode)) {
985 /*
986 * Yes. Is it a shift?
987 */
988 if (IE_IS_SHIFT(iecode)) {
989 /*
990 * Yes. Is it locking?
991 */
992 if (IE_SHIFT_IS_LOCKING(iecode)) {
993 /*
994 * Yes.
995 */
996 non_locking_shift = 0;
997 } else {
998 /*
999 * No. Remember the current
1000 * codeset, so we can revert
1001 * to it after the next IE.
1002 */
1003 non_locking_shift = 1;
1004 unshift_codeset = codeset;
1005 }
1006
1007 /*
1008 * Get the codeset.
1009 */
1010 codeset = IE_SHIFT_CODESET(iecode);
1011 }
1012 } else {
1013 /*
1014 * No. Get the IE length.
1015 */
1016 if (length == 0 || !ND_TTEST_1(p)) {
1017 if (!ndo->ndo_vflag) {
1018 ND_PRINT(", length %u", olen);
1019 }
1020 goto trunc;
1021 }
1022 ielength = GET_U_1(p);
1023 p++;
1024 length--;
1025
1026 /* lets do the full IE parsing only in verbose mode
1027 * however some IEs (DLCI Status, Link Verify)
1028 * are also interesting in non-verbose mode */
1029 if (ndo->ndo_vflag) {
1030 ND_PRINT("\n\t%s IE (0x%02x), length %u: ",
1031 tok2str(fr_q933_ie_codesets[codeset],
1032 "unknown", iecode),
1033 iecode,
1034 ielength);
1035 }
1036
1037 /* sanity checks */
1038 if (iecode == 0 || ielength == 0) {
1039 return;
1040 }
1041 if (length < ielength || !ND_TTEST_LEN(p, ielength)) {
1042 if (!ndo->ndo_vflag) {
1043 ND_PRINT(", length %u", olen);
1044 }
1045 goto trunc;
1046 }
1047
1048 ie_is_known = 0;
1049 if (fr_q933_print_ie_codeset[codeset] != NULL) {
1050 ie_is_known = fr_q933_print_ie_codeset[codeset](ndo, iecode, ielength, p);
1051 }
1052
1053 if (ie_is_known) {
1054 /*
1055 * Known IE; do we want to see a hexdump
1056 * of it?
1057 */
1058 if (ndo->ndo_vflag > 1) {
1059 /* Yes. */
1060 print_unknown_data(ndo, p, "\n\t ", ielength);
1061 }
1062 } else {
1063 /*
1064 * Unknown IE; if we're printing verbosely,
1065 * print its content in hex.
1066 */
1067 if (ndo->ndo_vflag >= 1) {
1068 print_unknown_data(ndo, p, "\n\t", ielength);
1069 }
1070 }
1071
1072 length -= ielength;
1073 p += ielength;
1074 }
1075 }
1076 if (!ndo->ndo_vflag) {
1077 ND_PRINT(", length %u", olen);
1078 }
1079 return;
1080
1081 trunc:
1082 nd_print_trunc(ndo);
1083 }
1084
1085 static int
1086 fr_q933_print_ie_codeset_0_5(netdissect_options *ndo, u_int iecode,
1087 u_int ielength, const u_char *p)
1088 {
1089 u_int dlci;
1090
1091 switch (iecode) {
1092
1093 case FR_LMI_ANSI_REPORT_TYPE_IE: /* fall through */
1094 case FR_LMI_CCITT_REPORT_TYPE_IE:
1095 if (ielength < 1) {
1096 if (!ndo->ndo_vflag) {
1097 ND_PRINT(", ");
1098 }
1099 ND_PRINT("Invalid REPORT TYPE IE");
1100 return 1;
1101 }
1102 if (ndo->ndo_vflag) {
1103 ND_PRINT("%s (%u)",
1104 tok2str(fr_lmi_report_type_ie_values,"unknown",GET_U_1(p)),
1105 GET_U_1(p));
1106 }
1107 return 1;
1108
1109 case FR_LMI_ANSI_LINK_VERIFY_IE: /* fall through */
1110 case FR_LMI_CCITT_LINK_VERIFY_IE:
1111 case FR_LMI_ANSI_LINK_VERIFY_IE_91:
1112 if (!ndo->ndo_vflag) {
1113 ND_PRINT(", ");
1114 }
1115 if (ielength < 2) {
1116 ND_PRINT("Invalid LINK VERIFY IE");
1117 return 1;
1118 }
1119 ND_PRINT("TX Seq: %3d, RX Seq: %3d", GET_U_1(p), GET_U_1(p + 1));
1120 return 1;
1121
1122 case FR_LMI_ANSI_PVC_STATUS_IE: /* fall through */
1123 case FR_LMI_CCITT_PVC_STATUS_IE:
1124 if (!ndo->ndo_vflag) {
1125 ND_PRINT(", ");
1126 }
1127 /* now parse the DLCI information element. */
1128 if ((ielength < 3) ||
1129 (GET_U_1(p) & 0x80) ||
1130 ((ielength == 3) && !(GET_U_1(p + 1) & 0x80)) ||
1131 ((ielength == 4) &&
1132 ((GET_U_1(p + 1) & 0x80) || !(GET_U_1(p + 2) & 0x80))) ||
1133 ((ielength == 5) &&
1134 ((GET_U_1(p + 1) & 0x80) || (GET_U_1(p + 2) & 0x80) ||
1135 !(GET_U_1(p + 3) & 0x80))) ||
1136 (ielength > 5) ||
1137 !(GET_U_1(p + ielength - 1) & 0x80)) {
1138 ND_PRINT("Invalid DLCI in PVC STATUS IE");
1139 return 1;
1140 }
1141
1142 dlci = ((GET_U_1(p) & 0x3F) << 4) | ((GET_U_1(p + 1) & 0x78) >> 3);
1143 if (ielength == 4) {
1144 dlci = (dlci << 6) | ((GET_U_1(p + 2) & 0x7E) >> 1);
1145 } else if (ielength == 5) {
1146 dlci = (dlci << 13) | (GET_U_1(p + 2) & 0x7F) | ((GET_U_1(p + 3) & 0x7E) >> 1);
1147 }
1148
1149 ND_PRINT("DLCI %u: status %s%s", dlci,
1150 GET_U_1(p + ielength - 1) & 0x8 ? "New, " : "",
1151 GET_U_1(p + ielength - 1) & 0x2 ? "Active" : "Inactive");
1152 return 1;
1153 }
1154
1155 return 0;
1156 }