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 #ifdef HAVE_CONFIG_H
25 #include <config.h>
26 #endif
27
28 #include "netdissect-stdinc.h"
29
30 #include <stdio.h>
31 #include <string.h>
32
33 #include "netdissect.h"
34 #include "addrtoname.h"
35 #include "ethertype.h"
36 #include "llc.h"
37 #include "nlpid.h"
38 #include "extract.h"
39
40 static void frf15_print(netdissect_options *ndo, const u_char *, u_int);
41
42 /*
43 * the frame relay header has a variable length
44 *
45 * the EA bit determines if there is another byte
46 * in the header
47 *
48 * minimum header length is 2 bytes
49 * maximum header length is 4 bytes
50 *
51 * 7 6 5 4 3 2 1 0
52 * +----+----+----+----+----+----+----+----+
53 * | DLCI (6 bits) | CR | EA |
54 * +----+----+----+----+----+----+----+----+
55 * | DLCI (4 bits) |FECN|BECN| DE | EA |
56 * +----+----+----+----+----+----+----+----+
57 * | DLCI (7 bits) | EA |
58 * +----+----+----+----+----+----+----+----+
59 * | DLCI (6 bits) |SDLC| EA |
60 * +----+----+----+----+----+----+----+----+
61 */
62
63 #define FR_EA_BIT 0x01
64
65 #define FR_CR_BIT 0x02000000
66 #define FR_DE_BIT 0x00020000
67 #define FR_BECN_BIT 0x00040000
68 #define FR_FECN_BIT 0x00080000
69 #define FR_SDLC_BIT 0x00000002
70
71
72 static const struct tok fr_header_flag_values[] = {
73 { FR_CR_BIT, "C!" },
74 { FR_DE_BIT, "DE" },
75 { FR_BECN_BIT, "BECN" },
76 { FR_FECN_BIT, "FECN" },
77 { FR_SDLC_BIT, "sdlcore" },
78 { 0, NULL }
79 };
80
81 /* FRF.15 / FRF.16 */
82 #define MFR_B_BIT 0x80
83 #define MFR_E_BIT 0x40
84 #define MFR_C_BIT 0x20
85 #define MFR_BEC_MASK (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
86 #define MFR_CTRL_FRAME (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
87 #define MFR_FRAG_FRAME (MFR_B_BIT | MFR_E_BIT )
88
89 static const struct tok frf_flag_values[] = {
90 { MFR_B_BIT, "Begin" },
91 { MFR_E_BIT, "End" },
92 { MFR_C_BIT, "Control" },
93 { 0, NULL }
94 };
95
96 /* Finds out Q.922 address length, DLCI and flags. Returns 1 on success,
97 * 0 on invalid address, -1 on truncated packet
98 * save the flags dep. on address length
99 */
parse_q922_header(netdissect_options * ndo,const u_char * p,u_int * dlci,u_int * addr_len,uint32_t * flags,u_int length)100 static int parse_q922_header(netdissect_options *ndo,
101 const u_char *p, u_int *dlci,
102 u_int *addr_len, uint32_t *flags, u_int length)
103 {
104 if (!ND_TTEST_1(p) || length < 1)
105 return -1;
106 if ((GET_U_1(p) & FR_EA_BIT))
107 return 0;
108
109 if (!ND_TTEST_1(p + 1) || length < 2)
110 return -1;
111 *addr_len = 2;
112 *dlci = ((GET_U_1(p) & 0xFC) << 2) | ((GET_U_1(p + 1) & 0xF0) >> 4);
113
114 *flags = ((GET_U_1(p) & 0x02) << 24) | /* CR flag */
115 ((GET_U_1(p + 1) & 0x0e) << 16); /* FECN,BECN,DE flags */
116
117 if (GET_U_1(p + 1) & FR_EA_BIT)
118 return 1; /* 2-byte Q.922 address */
119
120 p += 2;
121 length -= 2;
122 if (!ND_TTEST_1(p) || length < 1)
123 return -1;
124 (*addr_len)++; /* 3- or 4-byte Q.922 address */
125 if ((GET_U_1(p) & FR_EA_BIT) == 0) {
126 *dlci = (*dlci << 7) | (GET_U_1(p) >> 1);
127 (*addr_len)++; /* 4-byte Q.922 address */
128 p++;
129 length--;
130 }
131
132 if (!ND_TTEST_1(p) || length < 1)
133 return -1;
134 if ((GET_U_1(p) & FR_EA_BIT) == 0)
135 return 0; /* more than 4 bytes of Q.922 address? */
136
137 *flags = *flags | (GET_U_1(p) & 0x02); /* SDLC flag */
138
139 *dlci = (*dlci << 6) | (GET_U_1(p) >> 2);
140
141 return 1;
142 }
143
144 const char *
q922_string(netdissect_options * ndo,const u_char * p,u_int length)145 q922_string(netdissect_options *ndo, const u_char *p, u_int length)
146 {
147
148 static u_int dlci, addr_len;
149 static uint32_t flags;
150 static char buffer[sizeof("parse_q922_header() returned XXXXXXXXXXX")];
151 int ret;
152 memset(buffer, 0, sizeof(buffer));
153
154 ret = parse_q922_header(ndo, p, &dlci, &addr_len, &flags, length);
155 if (ret == 1) {
156 snprintf(buffer, sizeof(buffer), "DLCI %u", dlci);
157 return buffer;
158 } else if (ret == 0) {
159 return "<Invalid DLCI>";
160 } else if (ret == -1) {
161 return "<Truncated>";
162 } else {
163 snprintf(buffer, sizeof(buffer), "parse_q922_header() returned %d", ret);
164 return buffer;
165 }
166 }
167
168
169 /* Frame Relay packet structure, with flags and CRC removed
170
171 +---------------------------+
172 | Q.922 Address* |
173 +-- --+
174 | |
175 +---------------------------+
176 | Control (UI = 0x03) |
177 +---------------------------+
178 | Optional Pad (0x00) |
179 +---------------------------+
180 | NLPID |
181 +---------------------------+
182 | . |
183 | . |
184 | . |
185 | Data |
186 | . |
187 | . |
188 +---------------------------+
189
190 * Q.922 addresses, as presently defined, are two octets and
191 contain a 10-bit DLCI. In some networks Q.922 addresses
192 may optionally be increased to three or four octets.
193 */
194
195 static void
fr_hdr_print(netdissect_options * ndo,int length,u_int addr_len,u_int dlci,uint32_t flags,uint16_t nlpid)196 fr_hdr_print(netdissect_options *ndo, int length, u_int addr_len,
197 u_int dlci, uint32_t flags, uint16_t nlpid)
198 {
199 if (ndo->ndo_qflag) {
200 ND_PRINT("Q.922, DLCI %u, length %u: ",
201 dlci,
202 length);
203 } else {
204 if (nlpid <= 0xff) /* if its smaller than 256 then its a NLPID */
205 ND_PRINT("Q.922, hdr-len %u, DLCI %u, Flags [%s], NLPID %s (0x%02x), length %u: ",
206 addr_len,
207 dlci,
208 bittok2str(fr_header_flag_values, "none", flags),
209 tok2str(nlpid_values,"unknown", nlpid),
210 nlpid,
211 length);
212 else /* must be an ethertype */
213 ND_PRINT("Q.922, hdr-len %u, DLCI %u, Flags [%s], cisco-ethertype %s (0x%04x), length %u: ",
214 addr_len,
215 dlci,
216 bittok2str(fr_header_flag_values, "none", flags),
217 tok2str(ethertype_values, "unknown", nlpid),
218 nlpid,
219 length);
220 }
221 }
222
223 /* Frame Relay */
224 void
fr_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)225 fr_if_print(netdissect_options *ndo,
226 const struct pcap_pkthdr *h, const u_char *p)
227 {
228 u_int length = h->len;
229 u_int caplen = h->caplen;
230
231 ndo->ndo_protocol = "fr";
232 if (caplen < 4) { /* minimum frame header length */
233 nd_print_trunc(ndo);
234 ndo->ndo_ll_hdr_len += caplen;
235 return;
236 }
237
238 ndo->ndo_ll_hdr_len += fr_print(ndo, p, length);
239 }
240
241 u_int
fr_print(netdissect_options * ndo,const u_char * p,u_int length)242 fr_print(netdissect_options *ndo,
243 const u_char *p, u_int length)
244 {
245 int ret;
246 uint16_t extracted_ethertype;
247 u_int dlci;
248 u_int addr_len;
249 uint16_t nlpid;
250 u_int hdr_len;
251 uint32_t flags;
252
253 ndo->ndo_protocol = "fr";
254 ret = parse_q922_header(ndo, p, &dlci, &addr_len, &flags, length);
255 if (ret == -1)
256 goto trunc;
257 if (ret == 0) {
258 ND_PRINT("Q.922, invalid address");
259 return 0;
260 }
261
262 ND_TCHECK_1(p + addr_len);
263 if (length < addr_len + 1)
264 goto trunc;
265
266 if (GET_U_1(p + addr_len) != LLC_UI && dlci != 0) {
267 /*
268 * Let's figure out if we have Cisco-style encapsulation,
269 * with an Ethernet type (Cisco HDLC type?) following the
270 * address.
271 */
272 if (!ND_TTEST_2(p + addr_len) || length < addr_len + 2) {
273 /* no Ethertype */
274 ND_PRINT("UI %02x! ", GET_U_1(p + addr_len));
275 } else {
276 extracted_ethertype = GET_BE_U_2(p + addr_len);
277
278 if (ndo->ndo_eflag)
279 fr_hdr_print(ndo, length, addr_len, dlci,
280 flags, extracted_ethertype);
281
282 if (ethertype_print(ndo, extracted_ethertype,
283 p+addr_len+ETHERTYPE_LEN,
284 length-addr_len-ETHERTYPE_LEN,
285 ND_BYTES_AVAILABLE_AFTER(p)-addr_len-ETHERTYPE_LEN,
286 NULL, NULL) == 0)
287 /* ether_type not known, probably it wasn't one */
288 ND_PRINT("UI %02x! ", GET_U_1(p + addr_len));
289 else
290 return addr_len + 2;
291 }
292 }
293
294 ND_TCHECK_1(p + addr_len + 1);
295 if (length < addr_len + 2)
296 goto trunc;
297
298 if (GET_U_1(p + addr_len + 1) == 0) {
299 /*
300 * Assume a pad byte after the control (UI) byte.
301 * A pad byte should only be used with 3-byte Q.922.
302 */
303 if (addr_len != 3)
304 ND_PRINT("Pad! ");
305 hdr_len = addr_len + 1 /* UI */ + 1 /* pad */ + 1 /* NLPID */;
306 } else {
307 /*
308 * Not a pad byte.
309 * A pad byte should be used with 3-byte Q.922.
310 */
311 if (addr_len == 3)
312 ND_PRINT("No pad! ");
313 hdr_len = addr_len + 1 /* UI */ + 1 /* NLPID */;
314 }
315
316 ND_TCHECK_1(p + hdr_len - 1);
317 if (length < hdr_len)
318 goto trunc;
319 nlpid = GET_U_1(p + hdr_len - 1);
320
321 if (ndo->ndo_eflag)
322 fr_hdr_print(ndo, length, addr_len, dlci, flags, nlpid);
323 p += hdr_len;
324 length -= hdr_len;
325
326 switch (nlpid) {
327 case NLPID_IP:
328 ip_print(ndo, p, length);
329 break;
330
331 case NLPID_IP6:
332 ip6_print(ndo, p, length);
333 break;
334
335 case NLPID_CLNP:
336 case NLPID_ESIS:
337 case NLPID_ISIS:
338 isoclns_print(ndo, p - 1, length + 1); /* OSI printers need the NLPID field */
339 break;
340
341 case NLPID_SNAP:
342 if (snap_print(ndo, p, length, ND_BYTES_AVAILABLE_AFTER(p), NULL, NULL, 0) == 0) {
343 /* ether_type not known, print raw packet */
344 if (!ndo->ndo_eflag)
345 fr_hdr_print(ndo, length + hdr_len, hdr_len,
346 dlci, flags, nlpid);
347 if (!ndo->ndo_suppress_default_print)
348 ND_DEFAULTPRINT(p - hdr_len, length + hdr_len);
349 }
350 break;
351
352 case NLPID_Q933:
353 q933_print(ndo, p, length);
354 break;
355
356 case NLPID_MFR:
357 frf15_print(ndo, p, length);
358 break;
359
360 case NLPID_PPP:
361 ppp_print(ndo, p, length);
362 break;
363
364 default:
365 if (!ndo->ndo_eflag)
366 fr_hdr_print(ndo, length + hdr_len, addr_len,
367 dlci, flags, nlpid);
368 if (!ndo->ndo_xflag)
369 ND_DEFAULTPRINT(p, length);
370 }
371
372 return hdr_len;
373
374 trunc:
375 nd_print_trunc(ndo);
376 return 0;
377
378 }
379
380 /* Multi Link Frame Relay (FRF.16) */
381 void
mfr_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,const u_char * p)382 mfr_if_print(netdissect_options *ndo,
383 const struct pcap_pkthdr *h, const u_char *p)
384 {
385 u_int length = h->len;
386 u_int caplen = h->caplen;
387
388 ndo->ndo_protocol = "mfr";
389 if (caplen < 2) { /* minimum frame header length */
390 nd_print_trunc(ndo);
391 ndo->ndo_ll_hdr_len += caplen;
392 return;
393 }
394
395 ndo->ndo_ll_hdr_len += mfr_print(ndo, p, length);
396 }
397
398
399 #define MFR_CTRL_MSG_ADD_LINK 1
400 #define MFR_CTRL_MSG_ADD_LINK_ACK 2
401 #define MFR_CTRL_MSG_ADD_LINK_REJ 3
402 #define MFR_CTRL_MSG_HELLO 4
403 #define MFR_CTRL_MSG_HELLO_ACK 5
404 #define MFR_CTRL_MSG_REMOVE_LINK 6
405 #define MFR_CTRL_MSG_REMOVE_LINK_ACK 7
406
407 static const struct tok mfr_ctrl_msg_values[] = {
408 { MFR_CTRL_MSG_ADD_LINK, "Add Link" },
409 { MFR_CTRL_MSG_ADD_LINK_ACK, "Add Link ACK" },
410 { MFR_CTRL_MSG_ADD_LINK_REJ, "Add Link Reject" },
411 { MFR_CTRL_MSG_HELLO, "Hello" },
412 { MFR_CTRL_MSG_HELLO_ACK, "Hello ACK" },
413 { MFR_CTRL_MSG_REMOVE_LINK, "Remove Link" },
414 { MFR_CTRL_MSG_REMOVE_LINK_ACK, "Remove Link ACK" },
415 { 0, NULL }
416 };
417
418 #define MFR_CTRL_IE_BUNDLE_ID 1
419 #define MFR_CTRL_IE_LINK_ID 2
420 #define MFR_CTRL_IE_MAGIC_NUM 3
421 #define MFR_CTRL_IE_TIMESTAMP 5
422 #define MFR_CTRL_IE_VENDOR_EXT 6
423 #define MFR_CTRL_IE_CAUSE 7
424
425 static const struct tok mfr_ctrl_ie_values[] = {
426 { MFR_CTRL_IE_BUNDLE_ID, "Bundle ID"},
427 { MFR_CTRL_IE_LINK_ID, "Link ID"},
428 { MFR_CTRL_IE_MAGIC_NUM, "Magic Number"},
429 { MFR_CTRL_IE_TIMESTAMP, "Timestamp"},
430 { MFR_CTRL_IE_VENDOR_EXT, "Vendor Extension"},
431 { MFR_CTRL_IE_CAUSE, "Cause"},
432 { 0, NULL }
433 };
434
435 #define MFR_ID_STRING_MAXLEN 50
436
437 struct ie_tlv_header_t {
438 uint8_t ie_type;
439 uint8_t ie_len;
440 };
441
442 u_int
mfr_print(netdissect_options * ndo,const u_char * p,u_int length)443 mfr_print(netdissect_options *ndo,
444 const u_char *p, u_int length)
445 {
446 u_int tlen,idx,hdr_len = 0;
447 uint16_t sequence_num;
448 uint8_t ie_type,ie_len;
449 const uint8_t *tptr;
450
451
452 /*
453 * FRF.16 Link Integrity Control Frame
454 *
455 * 7 6 5 4 3 2 1 0
456 * +----+----+----+----+----+----+----+----+
457 * | B | E | C=1| 0 0 0 0 | EA |
458 * +----+----+----+----+----+----+----+----+
459 * | 0 0 0 0 0 0 0 0 |
460 * +----+----+----+----+----+----+----+----+
461 * | message type |
462 * +----+----+----+----+----+----+----+----+
463 */
464
465 ndo->ndo_protocol = "mfr";
466
467 if (length < 4) { /* minimum frame header length */
468 ND_PRINT("[length %u < 4]", length);
469 nd_print_invalid(ndo);
470 return length;
471 }
472 ND_TCHECK_4(p);
473
474 if ((GET_U_1(p) & MFR_BEC_MASK) == MFR_CTRL_FRAME && GET_U_1(p + 1) == 0) {
475 ND_PRINT("FRF.16 Control, Flags [%s], %s, length %u",
476 bittok2str(frf_flag_values,"none",(GET_U_1(p) & MFR_BEC_MASK)),
477 tok2str(mfr_ctrl_msg_values,"Unknown Message (0x%02x)",GET_U_1(p + 2)),
478 length);
479 tptr = p + 3;
480 tlen = length -3;
481 hdr_len = 3;
482
483 if (!ndo->ndo_vflag)
484 return hdr_len;
485
486 while (tlen>sizeof(struct ie_tlv_header_t)) {
487 ND_TCHECK_LEN(tptr, sizeof(struct ie_tlv_header_t));
488 ie_type=GET_U_1(tptr);
489 ie_len=GET_U_1(tptr + 1);
490
491 ND_PRINT("\n\tIE %s (%u), length %u: ",
492 tok2str(mfr_ctrl_ie_values,"Unknown",ie_type),
493 ie_type,
494 ie_len);
495
496 /* infinite loop check */
497 if (ie_type == 0 || ie_len <= sizeof(struct ie_tlv_header_t))
498 return hdr_len;
499
500 ND_TCHECK_LEN(tptr, ie_len);
501 tptr+=sizeof(struct ie_tlv_header_t);
502 /* tlv len includes header */
503 ie_len-=sizeof(struct ie_tlv_header_t);
504 tlen-=sizeof(struct ie_tlv_header_t);
505
506 switch (ie_type) {
507
508 case MFR_CTRL_IE_MAGIC_NUM:
509 /* FRF.16.1 Section 3.4.3 Magic Number Information Element */
510 if (ie_len != 4) {
511 ND_PRINT("[IE data length %d != 4]", ie_len);
512 nd_print_invalid(ndo);
513 break;
514 }
515 ND_PRINT("0x%08x", GET_BE_U_4(tptr));
516 break;
517
518 case MFR_CTRL_IE_BUNDLE_ID: /* same message format */
519 case MFR_CTRL_IE_LINK_ID:
520 for (idx = 0; idx < ie_len && idx < MFR_ID_STRING_MAXLEN; idx++) {
521 if (GET_U_1(tptr + idx) != 0) /* don't print null termination */
522 fn_print_char(ndo, GET_U_1(tptr + idx));
523 else
524 break;
525 }
526 break;
527
528 case MFR_CTRL_IE_TIMESTAMP:
529 if (ie_len == sizeof(struct timeval)) {
530 ts_print(ndo, (const struct timeval *)tptr);
531 break;
532 }
533 /* fall through and hexdump if no unix timestamp */
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
frf15_print(netdissect_options * ndo,const u_char * p,u_int length)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
q933_print(netdissect_options * ndo,const u_char * p,u_int length)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
fr_q933_print_ie_codeset_0_5(netdissect_options * ndo,u_int iecode,u_int ielength,const u_char * p)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 }
1146 else if (ielength == 5) {
1147 dlci = (dlci << 13) | (GET_U_1(p + 2) & 0x7F) | ((GET_U_1(p + 3) & 0x7E) >> 1);
1148 }
1149
1150 ND_PRINT("DLCI %u: status %s%s", dlci,
1151 GET_U_1(p + ielength - 1) & 0x8 ? "New, " : "",
1152 GET_U_1(p + ielength - 1) & 0x2 ? "Active" : "Inactive");
1153 return 1;
1154 }
1155
1156 return 0;
1157 }
1158