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 #include "oui.h"
40
41 static void frf15_print(netdissect_options *ndo, const u_char *, u_int);
42
43 /*
44 * the frame relay header has a variable length
45 *
46 * the EA bit determines if there is another byte
47 * in the header
48 *
49 * minimum header length is 2 bytes
50 * maximum header length is 4 bytes
51 *
52 * 7 6 5 4 3 2 1 0
53 * +----+----+----+----+----+----+----+----+
54 * | DLCI (6 bits) | CR | EA |
55 * +----+----+----+----+----+----+----+----+
56 * | DLCI (4 bits) |FECN|BECN| DE | EA |
57 * +----+----+----+----+----+----+----+----+
58 * | DLCI (7 bits) | EA |
59 * +----+----+----+----+----+----+----+----+
60 * | DLCI (6 bits) |SDLC| EA |
61 * +----+----+----+----+----+----+----+----+
62 */
63
64 #define FR_EA_BIT 0x01
65
66 #define FR_CR_BIT 0x02000000
67 #define FR_DE_BIT 0x00020000
68 #define FR_BECN_BIT 0x00040000
69 #define FR_FECN_BIT 0x00080000
70 #define FR_SDLC_BIT 0x00000002
71
72
73 static const struct tok fr_header_flag_values[] = {
74 { FR_CR_BIT, "C!" },
75 { FR_DE_BIT, "DE" },
76 { FR_BECN_BIT, "BECN" },
77 { FR_FECN_BIT, "FECN" },
78 { FR_SDLC_BIT, "sdlcore" },
79 { 0, NULL }
80 };
81
82 /* FRF.15 / FRF.16 */
83 #define MFR_B_BIT 0x80
84 #define MFR_E_BIT 0x40
85 #define MFR_C_BIT 0x20
86 #define MFR_BEC_MASK (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
87 #define MFR_CTRL_FRAME (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
88 #define MFR_FRAG_FRAME (MFR_B_BIT | MFR_E_BIT )
89
90 static const struct tok frf_flag_values[] = {
91 { MFR_B_BIT, "Begin" },
92 { MFR_E_BIT, "End" },
93 { MFR_C_BIT, "Control" },
94 { 0, NULL }
95 };
96
97 /* Finds out Q.922 address length, DLCI and flags. Returns 1 on success,
98 * 0 on invalid address, -1 on truncated packet
99 * save the flags dep. on address length
100 */
parse_q922_addr(netdissect_options * ndo,const u_char * p,u_int * dlci,u_int * addr_len,uint8_t * flags,u_int length)101 static int parse_q922_addr(netdissect_options *ndo,
102 const u_char *p, u_int *dlci,
103 u_int *addr_len, uint8_t *flags, u_int length)
104 {
105 if (!ND_TTEST(p[0]) || length < 1)
106 return -1;
107 if ((p[0] & FR_EA_BIT))
108 return 0;
109
110 if (!ND_TTEST(p[1]) || length < 2)
111 return -1;
112 *addr_len = 2;
113 *dlci = ((p[0] & 0xFC) << 2) | ((p[1] & 0xF0) >> 4);
114
115 flags[0] = p[0] & 0x02; /* populate the first flag fields */
116 flags[1] = p[1] & 0x0c;
117 flags[2] = 0; /* clear the rest of the flags */
118 flags[3] = 0;
119
120 if (p[1] & FR_EA_BIT)
121 return 1; /* 2-byte Q.922 address */
122
123 p += 2;
124 length -= 2;
125 if (!ND_TTEST(p[0]) || length < 1)
126 return -1;
127 (*addr_len)++; /* 3- or 4-byte Q.922 address */
128 if ((p[0] & FR_EA_BIT) == 0) {
129 *dlci = (*dlci << 7) | (p[0] >> 1);
130 (*addr_len)++; /* 4-byte Q.922 address */
131 p++;
132 length--;
133 }
134
135 if (!ND_TTEST(p[0]) || length < 1)
136 return -1;
137 if ((p[0] & FR_EA_BIT) == 0)
138 return 0; /* more than 4 bytes of Q.922 address? */
139
140 flags[3] = p[0] & 0x02;
141
142 *dlci = (*dlci << 6) | (p[0] >> 2);
143
144 return 1;
145 }
146
147 char *
q922_string(netdissect_options * ndo,const u_char * p,u_int length)148 q922_string(netdissect_options *ndo, const u_char *p, u_int length)
149 {
150
151 static u_int dlci, addr_len;
152 static uint8_t flags[4];
153 static char buffer[sizeof("DLCI xxxxxxxxxx")];
154 memset(buffer, 0, sizeof(buffer));
155
156 if (parse_q922_addr(ndo, p, &dlci, &addr_len, flags, length) == 1){
157 snprintf(buffer, sizeof(buffer), "DLCI %u", dlci);
158 }
159
160 return buffer;
161 }
162
163
164 /* Frame Relay packet structure, with flags and CRC removed
165
166 +---------------------------+
167 | Q.922 Address* |
168 +-- --+
169 | |
170 +---------------------------+
171 | Control (UI = 0x03) |
172 +---------------------------+
173 | Optional Pad (0x00) |
174 +---------------------------+
175 | NLPID |
176 +---------------------------+
177 | . |
178 | . |
179 | . |
180 | Data |
181 | . |
182 | . |
183 +---------------------------+
184
185 * Q.922 addresses, as presently defined, are two octets and
186 contain a 10-bit DLCI. In some networks Q.922 addresses
187 may optionally be increased to three or four octets.
188 */
189
190 static void
fr_hdr_print(netdissect_options * ndo,int length,u_int addr_len,u_int dlci,uint8_t * flags,uint16_t nlpid)191 fr_hdr_print(netdissect_options *ndo,
192 int length, u_int addr_len, u_int dlci, uint8_t *flags, uint16_t nlpid)
193 {
194 if (ndo->ndo_qflag) {
195 ND_PRINT((ndo, "Q.922, DLCI %u, length %u: ",
196 dlci,
197 length));
198 } else {
199 if (nlpid <= 0xff) /* if its smaller than 256 then its a NLPID */
200 ND_PRINT((ndo, "Q.922, hdr-len %u, DLCI %u, Flags [%s], NLPID %s (0x%02x), length %u: ",
201 addr_len,
202 dlci,
203 bittok2str(fr_header_flag_values, "none", EXTRACT_32BITS(flags)),
204 tok2str(nlpid_values,"unknown", nlpid),
205 nlpid,
206 length));
207 else /* must be an ethertype */
208 ND_PRINT((ndo, "Q.922, hdr-len %u, DLCI %u, Flags [%s], cisco-ethertype %s (0x%04x), length %u: ",
209 addr_len,
210 dlci,
211 bittok2str(fr_header_flag_values, "none", EXTRACT_32BITS(flags)),
212 tok2str(ethertype_values, "unknown", nlpid),
213 nlpid,
214 length));
215 }
216 }
217
218 u_int
fr_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,register const u_char * p)219 fr_if_print(netdissect_options *ndo,
220 const struct pcap_pkthdr *h, register const u_char *p)
221 {
222 register u_int length = h->len;
223 register u_int caplen = h->caplen;
224
225 ND_TCHECK2(*p, 4); /* minimum frame header length */
226
227 if ((length = fr_print(ndo, p, length)) == 0)
228 return (0);
229 else
230 return length;
231 trunc:
232 ND_PRINT((ndo, "[|fr]"));
233 return caplen;
234 }
235
236 u_int
fr_print(netdissect_options * ndo,register const u_char * p,u_int length)237 fr_print(netdissect_options *ndo,
238 register const u_char *p, u_int length)
239 {
240 int ret;
241 uint16_t extracted_ethertype;
242 u_int dlci;
243 u_int addr_len;
244 uint16_t nlpid;
245 u_int hdr_len;
246 uint8_t flags[4];
247
248 ret = parse_q922_addr(ndo, p, &dlci, &addr_len, flags, length);
249 if (ret == -1)
250 goto trunc;
251 if (ret == 0) {
252 ND_PRINT((ndo, "Q.922, invalid address"));
253 return 0;
254 }
255
256 ND_TCHECK(p[addr_len]);
257 if (length < addr_len + 1)
258 goto trunc;
259
260 if (p[addr_len] != LLC_UI && dlci != 0) {
261 /*
262 * Let's figure out if we have Cisco-style encapsulation,
263 * with an Ethernet type (Cisco HDLC type?) following the
264 * address.
265 */
266 if (!ND_TTEST2(p[addr_len], 2) || length < addr_len + 2) {
267 /* no Ethertype */
268 ND_PRINT((ndo, "UI %02x! ", p[addr_len]));
269 } else {
270 extracted_ethertype = EXTRACT_16BITS(p+addr_len);
271
272 if (ndo->ndo_eflag)
273 fr_hdr_print(ndo, length, addr_len, dlci,
274 flags, extracted_ethertype);
275
276 if (ethertype_print(ndo, extracted_ethertype,
277 p+addr_len+ETHERTYPE_LEN,
278 length-addr_len-ETHERTYPE_LEN,
279 ndo->ndo_snapend-p-addr_len-ETHERTYPE_LEN,
280 NULL, NULL) == 0)
281 /* ether_type not known, probably it wasn't one */
282 ND_PRINT((ndo, "UI %02x! ", p[addr_len]));
283 else
284 return addr_len + 2;
285 }
286 }
287
288 ND_TCHECK(p[addr_len+1]);
289 if (length < addr_len + 2)
290 goto trunc;
291
292 if (p[addr_len + 1] == 0) {
293 /*
294 * Assume a pad byte after the control (UI) byte.
295 * A pad byte should only be used with 3-byte Q.922.
296 */
297 if (addr_len != 3)
298 ND_PRINT((ndo, "Pad! "));
299 hdr_len = addr_len + 1 /* UI */ + 1 /* pad */ + 1 /* NLPID */;
300 } else {
301 /*
302 * Not a pad byte.
303 * A pad byte should be used with 3-byte Q.922.
304 */
305 if (addr_len == 3)
306 ND_PRINT((ndo, "No pad! "));
307 hdr_len = addr_len + 1 /* UI */ + 1 /* NLPID */;
308 }
309
310 ND_TCHECK(p[hdr_len - 1]);
311 if (length < hdr_len)
312 goto trunc;
313 nlpid = p[hdr_len - 1];
314
315 if (ndo->ndo_eflag)
316 fr_hdr_print(ndo, length, addr_len, dlci, flags, nlpid);
317 p += hdr_len;
318 length -= hdr_len;
319
320 switch (nlpid) {
321 case NLPID_IP:
322 ip_print(ndo, p, length);
323 break;
324
325 case NLPID_IP6:
326 ip6_print(ndo, p, length);
327 break;
328
329 case NLPID_CLNP:
330 case NLPID_ESIS:
331 case NLPID_ISIS:
332 isoclns_print(ndo, p - 1, length + 1, ndo->ndo_snapend - p + 1); /* OSI printers need the NLPID field */
333 break;
334
335 case NLPID_SNAP:
336 if (snap_print(ndo, p, length, ndo->ndo_snapend - p, NULL, NULL, 0) == 0) {
337 /* ether_type not known, print raw packet */
338 if (!ndo->ndo_eflag)
339 fr_hdr_print(ndo, length + hdr_len, hdr_len,
340 dlci, flags, nlpid);
341 if (!ndo->ndo_suppress_default_print)
342 ND_DEFAULTPRINT(p - hdr_len, length + hdr_len);
343 }
344 break;
345
346 case NLPID_Q933:
347 q933_print(ndo, p, length);
348 break;
349
350 case NLPID_MFR:
351 frf15_print(ndo, p, length);
352 break;
353
354 case NLPID_PPP:
355 ppp_print(ndo, p, length);
356 break;
357
358 default:
359 if (!ndo->ndo_eflag)
360 fr_hdr_print(ndo, length + hdr_len, addr_len,
361 dlci, flags, nlpid);
362 if (!ndo->ndo_xflag)
363 ND_DEFAULTPRINT(p, length);
364 }
365
366 return hdr_len;
367
368 trunc:
369 ND_PRINT((ndo, "[|fr]"));
370 return 0;
371
372 }
373
374 u_int
mfr_if_print(netdissect_options * ndo,const struct pcap_pkthdr * h,register const u_char * p)375 mfr_if_print(netdissect_options *ndo,
376 const struct pcap_pkthdr *h, register const u_char *p)
377 {
378 register u_int length = h->len;
379 register u_int caplen = h->caplen;
380
381 ND_TCHECK2(*p, 2); /* minimum frame header length */
382
383 if ((length = mfr_print(ndo, p, length)) == 0)
384 return (0);
385 else
386 return length;
387 trunc:
388 ND_PRINT((ndo, "[|mfr]"));
389 return caplen;
390 }
391
392
393 #define MFR_CTRL_MSG_ADD_LINK 1
394 #define MFR_CTRL_MSG_ADD_LINK_ACK 2
395 #define MFR_CTRL_MSG_ADD_LINK_REJ 3
396 #define MFR_CTRL_MSG_HELLO 4
397 #define MFR_CTRL_MSG_HELLO_ACK 5
398 #define MFR_CTRL_MSG_REMOVE_LINK 6
399 #define MFR_CTRL_MSG_REMOVE_LINK_ACK 7
400
401 static const struct tok mfr_ctrl_msg_values[] = {
402 { MFR_CTRL_MSG_ADD_LINK, "Add Link" },
403 { MFR_CTRL_MSG_ADD_LINK_ACK, "Add Link ACK" },
404 { MFR_CTRL_MSG_ADD_LINK_REJ, "Add Link Reject" },
405 { MFR_CTRL_MSG_HELLO, "Hello" },
406 { MFR_CTRL_MSG_HELLO_ACK, "Hello ACK" },
407 { MFR_CTRL_MSG_REMOVE_LINK, "Remove Link" },
408 { MFR_CTRL_MSG_REMOVE_LINK_ACK, "Remove Link ACK" },
409 { 0, NULL }
410 };
411
412 #define MFR_CTRL_IE_BUNDLE_ID 1
413 #define MFR_CTRL_IE_LINK_ID 2
414 #define MFR_CTRL_IE_MAGIC_NUM 3
415 #define MFR_CTRL_IE_TIMESTAMP 5
416 #define MFR_CTRL_IE_VENDOR_EXT 6
417 #define MFR_CTRL_IE_CAUSE 7
418
419 static const struct tok mfr_ctrl_ie_values[] = {
420 { MFR_CTRL_IE_BUNDLE_ID, "Bundle ID"},
421 { MFR_CTRL_IE_LINK_ID, "Link ID"},
422 { MFR_CTRL_IE_MAGIC_NUM, "Magic Number"},
423 { MFR_CTRL_IE_TIMESTAMP, "Timestamp"},
424 { MFR_CTRL_IE_VENDOR_EXT, "Vendor Extension"},
425 { MFR_CTRL_IE_CAUSE, "Cause"},
426 { 0, NULL }
427 };
428
429 #define MFR_ID_STRING_MAXLEN 50
430
431 struct ie_tlv_header_t {
432 uint8_t ie_type;
433 uint8_t ie_len;
434 };
435
436 u_int
mfr_print(netdissect_options * ndo,register const u_char * p,u_int length)437 mfr_print(netdissect_options *ndo,
438 register const u_char *p, u_int length)
439 {
440 u_int tlen,idx,hdr_len = 0;
441 uint16_t sequence_num;
442 uint8_t ie_type,ie_len;
443 const uint8_t *tptr;
444
445
446 /*
447 * FRF.16 Link Integrity Control Frame
448 *
449 * 7 6 5 4 3 2 1 0
450 * +----+----+----+----+----+----+----+----+
451 * | B | E | C=1| 0 0 0 0 | EA |
452 * +----+----+----+----+----+----+----+----+
453 * | 0 0 0 0 0 0 0 0 |
454 * +----+----+----+----+----+----+----+----+
455 * | message type |
456 * +----+----+----+----+----+----+----+----+
457 */
458
459 ND_TCHECK2(*p, 4); /* minimum frame header length */
460
461 if ((p[0] & MFR_BEC_MASK) == MFR_CTRL_FRAME && p[1] == 0) {
462 ND_PRINT((ndo, "FRF.16 Control, Flags [%s], %s, length %u",
463 bittok2str(frf_flag_values,"none",(p[0] & MFR_BEC_MASK)),
464 tok2str(mfr_ctrl_msg_values,"Unknown Message (0x%02x)",p[2]),
465 length));
466 tptr = p + 3;
467 tlen = length -3;
468 hdr_len = 3;
469
470 if (!ndo->ndo_vflag)
471 return hdr_len;
472
473 while (tlen>sizeof(struct ie_tlv_header_t)) {
474 ND_TCHECK2(*tptr, sizeof(struct ie_tlv_header_t));
475 ie_type=tptr[0];
476 ie_len=tptr[1];
477
478 ND_PRINT((ndo, "\n\tIE %s (%u), length %u: ",
479 tok2str(mfr_ctrl_ie_values,"Unknown",ie_type),
480 ie_type,
481 ie_len));
482
483 /* infinite loop check */
484 if (ie_type == 0 || ie_len <= sizeof(struct ie_tlv_header_t))
485 return hdr_len;
486
487 ND_TCHECK2(*tptr, ie_len);
488 tptr+=sizeof(struct ie_tlv_header_t);
489 /* tlv len includes header */
490 ie_len-=sizeof(struct ie_tlv_header_t);
491 tlen-=sizeof(struct ie_tlv_header_t);
492
493 switch (ie_type) {
494
495 case MFR_CTRL_IE_MAGIC_NUM:
496 ND_PRINT((ndo, "0x%08x", EXTRACT_32BITS(tptr)));
497 break;
498
499 case MFR_CTRL_IE_BUNDLE_ID: /* same message format */
500 case MFR_CTRL_IE_LINK_ID:
501 for (idx = 0; idx < ie_len && idx < MFR_ID_STRING_MAXLEN; idx++) {
502 if (*(tptr+idx) != 0) /* don't print null termination */
503 safeputchar(ndo, *(tptr + idx));
504 else
505 break;
506 }
507 break;
508
509 case MFR_CTRL_IE_TIMESTAMP:
510 if (ie_len == sizeof(struct timeval)) {
511 ts_print(ndo, (const struct timeval *)tptr);
512 break;
513 }
514 /* fall through and hexdump if no unix timestamp */
515
516 /*
517 * FIXME those are the defined IEs that lack a decoder
518 * you are welcome to contribute code ;-)
519 */
520
521 case MFR_CTRL_IE_VENDOR_EXT:
522 case MFR_CTRL_IE_CAUSE:
523
524 default:
525 if (ndo->ndo_vflag <= 1)
526 print_unknown_data(ndo, tptr, "\n\t ", ie_len);
527 break;
528 }
529
530 /* do we want to see a hexdump of the IE ? */
531 if (ndo->ndo_vflag > 1 )
532 print_unknown_data(ndo, tptr, "\n\t ", ie_len);
533
534 tlen-=ie_len;
535 tptr+=ie_len;
536 }
537 return hdr_len;
538 }
539 /*
540 * FRF.16 Fragmentation Frame
541 *
542 * 7 6 5 4 3 2 1 0
543 * +----+----+----+----+----+----+----+----+
544 * | B | E | C=0|seq. (high 4 bits) | EA |
545 * +----+----+----+----+----+----+----+----+
546 * | sequence (low 8 bits) |
547 * +----+----+----+----+----+----+----+----+
548 * | DLCI (6 bits) | CR | EA |
549 * +----+----+----+----+----+----+----+----+
550 * | DLCI (4 bits) |FECN|BECN| DE | EA |
551 * +----+----+----+----+----+----+----+----+
552 */
553
554 sequence_num = (p[0]&0x1e)<<7 | p[1];
555 /* whole packet or first fragment ? */
556 if ((p[0] & MFR_BEC_MASK) == MFR_FRAG_FRAME ||
557 (p[0] & MFR_BEC_MASK) == MFR_B_BIT) {
558 ND_PRINT((ndo, "FRF.16 Frag, seq %u, Flags [%s], ",
559 sequence_num,
560 bittok2str(frf_flag_values,"none",(p[0] & MFR_BEC_MASK))));
561 hdr_len = 2;
562 fr_print(ndo, p+hdr_len,length-hdr_len);
563 return hdr_len;
564 }
565
566 /* must be a middle or the last fragment */
567 ND_PRINT((ndo, "FRF.16 Frag, seq %u, Flags [%s]",
568 sequence_num,
569 bittok2str(frf_flag_values,"none",(p[0] & MFR_BEC_MASK))));
570 print_unknown_data(ndo, p, "\n\t", length);
571
572 return hdr_len;
573
574 trunc:
575 ND_PRINT((ndo, "[|mfr]"));
576 return length;
577 }
578
579 /* an NLPID of 0xb1 indicates a 2-byte
580 * FRF.15 header
581 *
582 * 7 6 5 4 3 2 1 0
583 * +----+----+----+----+----+----+----+----+
584 * ~ Q.922 header ~
585 * +----+----+----+----+----+----+----+----+
586 * | NLPID (8 bits) | NLPID=0xb1
587 * +----+----+----+----+----+----+----+----+
588 * | B | E | C |seq. (high 4 bits) | R |
589 * +----+----+----+----+----+----+----+----+
590 * | sequence (low 8 bits) |
591 * +----+----+----+----+----+----+----+----+
592 */
593
594 #define FR_FRF15_FRAGTYPE 0x01
595
596 static void
frf15_print(netdissect_options * ndo,const u_char * p,u_int length)597 frf15_print(netdissect_options *ndo,
598 const u_char *p, u_int length)
599 {
600 uint16_t sequence_num, flags;
601
602 if (length < 2)
603 goto trunc;
604 ND_TCHECK2(*p, 2);
605
606 flags = p[0]&MFR_BEC_MASK;
607 sequence_num = (p[0]&0x1e)<<7 | p[1];
608
609 ND_PRINT((ndo, "FRF.15, seq 0x%03x, Flags [%s],%s Fragmentation, length %u",
610 sequence_num,
611 bittok2str(frf_flag_values,"none",flags),
612 p[0]&FR_FRF15_FRAGTYPE ? "Interface" : "End-to-End",
613 length));
614
615 /* TODO:
616 * depending on all permutations of the B, E and C bit
617 * dig as deep as we can - e.g. on the first (B) fragment
618 * there is enough payload to print the IP header
619 * on non (B) fragments it depends if the fragmentation
620 * model is end-to-end or interface based wether we want to print
621 * another Q.922 header
622 */
623 return;
624
625 trunc:
626 ND_PRINT((ndo, "[|frf.15]"));
627 }
628
629 /*
630 * Q.933 decoding portion for framerelay specific.
631 */
632
633 /* Q.933 packet format
634 Format of Other Protocols
635 using Q.933 NLPID
636 +-------------------------------+
637 | Q.922 Address |
638 +---------------+---------------+
639 |Control 0x03 | NLPID 0x08 |
640 +---------------+---------------+
641 | L2 Protocol ID |
642 | octet 1 | octet 2 |
643 +-------------------------------+
644 | L3 Protocol ID |
645 | octet 2 | octet 2 |
646 +-------------------------------+
647 | Protocol Data |
648 +-------------------------------+
649 | FCS |
650 +-------------------------------+
651 */
652
653 /* L2 (Octet 1)- Call Reference Usually is 0x0 */
654
655 /*
656 * L2 (Octet 2)- Message Types definition 1 byte long.
657 */
658 /* Call Establish */
659 #define MSG_TYPE_ESC_TO_NATIONAL 0x00
660 #define MSG_TYPE_ALERT 0x01
661 #define MSG_TYPE_CALL_PROCEEDING 0x02
662 #define MSG_TYPE_CONNECT 0x07
663 #define MSG_TYPE_CONNECT_ACK 0x0F
664 #define MSG_TYPE_PROGRESS 0x03
665 #define MSG_TYPE_SETUP 0x05
666 /* Call Clear */
667 #define MSG_TYPE_DISCONNECT 0x45
668 #define MSG_TYPE_RELEASE 0x4D
669 #define MSG_TYPE_RELEASE_COMPLETE 0x5A
670 #define MSG_TYPE_RESTART 0x46
671 #define MSG_TYPE_RESTART_ACK 0x4E
672 /* Status */
673 #define MSG_TYPE_STATUS 0x7D
674 #define MSG_TYPE_STATUS_ENQ 0x75
675
676 static const struct tok fr_q933_msg_values[] = {
677 { MSG_TYPE_ESC_TO_NATIONAL, "ESC to National" },
678 { MSG_TYPE_ALERT, "Alert" },
679 { MSG_TYPE_CALL_PROCEEDING, "Call proceeding" },
680 { MSG_TYPE_CONNECT, "Connect" },
681 { MSG_TYPE_CONNECT_ACK, "Connect ACK" },
682 { MSG_TYPE_PROGRESS, "Progress" },
683 { MSG_TYPE_SETUP, "Setup" },
684 { MSG_TYPE_DISCONNECT, "Disconnect" },
685 { MSG_TYPE_RELEASE, "Release" },
686 { MSG_TYPE_RELEASE_COMPLETE, "Release Complete" },
687 { MSG_TYPE_RESTART, "Restart" },
688 { MSG_TYPE_RESTART_ACK, "Restart ACK" },
689 { MSG_TYPE_STATUS, "Status Reply" },
690 { MSG_TYPE_STATUS_ENQ, "Status Enquiry" },
691 { 0, NULL }
692 };
693
694 #define IE_IS_SINGLE_OCTET(iecode) ((iecode) & 0x80)
695 #define IE_IS_SHIFT(iecode) (((iecode) & 0xF0) == 0x90)
696 #define IE_SHIFT_IS_NON_LOCKING(iecode) ((iecode) & 0x08)
697 #define IE_SHIFT_IS_LOCKING(iecode) (!(IE_SHIFT_IS_NON_LOCKING(iecode)))
698 #define IE_SHIFT_CODESET(iecode) ((iecode) & 0x07)
699
700 #define FR_LMI_ANSI_REPORT_TYPE_IE 0x01
701 #define FR_LMI_ANSI_LINK_VERIFY_IE_91 0x19 /* details? */
702 #define FR_LMI_ANSI_LINK_VERIFY_IE 0x03
703 #define FR_LMI_ANSI_PVC_STATUS_IE 0x07
704
705 #define FR_LMI_CCITT_REPORT_TYPE_IE 0x51
706 #define FR_LMI_CCITT_LINK_VERIFY_IE 0x53
707 #define FR_LMI_CCITT_PVC_STATUS_IE 0x57
708
709 static const struct tok fr_q933_ie_values_codeset_0_5[] = {
710 { FR_LMI_ANSI_REPORT_TYPE_IE, "ANSI Report Type" },
711 { FR_LMI_ANSI_LINK_VERIFY_IE_91, "ANSI Link Verify" },
712 { FR_LMI_ANSI_LINK_VERIFY_IE, "ANSI Link Verify" },
713 { FR_LMI_ANSI_PVC_STATUS_IE, "ANSI PVC Status" },
714 { FR_LMI_CCITT_REPORT_TYPE_IE, "CCITT Report Type" },
715 { FR_LMI_CCITT_LINK_VERIFY_IE, "CCITT Link Verify" },
716 { FR_LMI_CCITT_PVC_STATUS_IE, "CCITT PVC Status" },
717 { 0, NULL }
718 };
719
720 #define FR_LMI_REPORT_TYPE_IE_FULL_STATUS 0
721 #define FR_LMI_REPORT_TYPE_IE_LINK_VERIFY 1
722 #define FR_LMI_REPORT_TYPE_IE_ASYNC_PVC 2
723
724 static const struct tok fr_lmi_report_type_ie_values[] = {
725 { FR_LMI_REPORT_TYPE_IE_FULL_STATUS, "Full Status" },
726 { FR_LMI_REPORT_TYPE_IE_LINK_VERIFY, "Link verify" },
727 { FR_LMI_REPORT_TYPE_IE_ASYNC_PVC, "Async PVC Status" },
728 { 0, NULL }
729 };
730
731 /* array of 16 codesets - currently we only support codepage 0 and 5 */
732 static const struct tok *fr_q933_ie_codesets[] = {
733 fr_q933_ie_values_codeset_0_5,
734 NULL,
735 NULL,
736 NULL,
737 NULL,
738 fr_q933_ie_values_codeset_0_5,
739 NULL,
740 NULL,
741 NULL,
742 NULL,
743 NULL,
744 NULL,
745 NULL,
746 NULL,
747 NULL,
748 NULL
749 };
750
751 static int fr_q933_print_ie_codeset_0_5(netdissect_options *ndo, u_int iecode,
752 u_int ielength, const u_char *p);
753
754 typedef int (*codeset_pr_func_t)(netdissect_options *, u_int iecode,
755 u_int ielength, const u_char *p);
756
757 /* array of 16 codesets - currently we only support codepage 0 and 5 */
758 static const codeset_pr_func_t fr_q933_print_ie_codeset[] = {
759 fr_q933_print_ie_codeset_0_5,
760 NULL,
761 NULL,
762 NULL,
763 NULL,
764 fr_q933_print_ie_codeset_0_5,
765 NULL,
766 NULL,
767 NULL,
768 NULL,
769 NULL,
770 NULL,
771 NULL,
772 NULL,
773 NULL,
774 NULL
775 };
776
777 /*
778 * ITU-T Q.933.
779 *
780 * p points to octet 2, the octet containing the length of the
781 * call reference value, so p[n] is octet n+2 ("octet X" is as
782 * used in Q.931/Q.933).
783 *
784 * XXX - actually used both for Q.931 and Q.933.
785 */
786 void
q933_print(netdissect_options * ndo,const u_char * p,u_int length)787 q933_print(netdissect_options *ndo,
788 const u_char *p, u_int length)
789 {
790 u_int olen;
791 u_int call_ref_length, i;
792 uint8_t call_ref[15]; /* maximum length - length field is 4 bits */
793 u_int msgtype;
794 u_int iecode;
795 u_int ielength;
796 u_int codeset = 0;
797 u_int is_ansi = 0;
798 u_int ie_is_known;
799 u_int non_locking_shift;
800 u_int unshift_codeset;
801
802 ND_PRINT((ndo, "%s", ndo->ndo_eflag ? "" : "Q.933"));
803
804 if (length == 0 || !ND_TTEST(*p)) {
805 if (!ndo->ndo_eflag)
806 ND_PRINT((ndo, ", "));
807 ND_PRINT((ndo, "length %u", length));
808 goto trunc;
809 }
810
811 /*
812 * Get the length of the call reference value.
813 */
814 olen = length; /* preserve the original length for display */
815 call_ref_length = (*p) & 0x0f;
816 p++;
817 length--;
818
819 /*
820 * Get the call reference value.
821 */
822 for (i = 0; i < call_ref_length; i++) {
823 if (length == 0 || !ND_TTEST(*p)) {
824 if (!ndo->ndo_eflag)
825 ND_PRINT((ndo, ", "));
826 ND_PRINT((ndo, "length %u", olen));
827 goto trunc;
828 }
829 call_ref[i] = *p;
830 p++;
831 length--;
832 }
833
834 /*
835 * Get the message type.
836 */
837 if (length == 0 || !ND_TTEST(*p)) {
838 if (!ndo->ndo_eflag)
839 ND_PRINT((ndo, ", "));
840 ND_PRINT((ndo, "length %u", olen));
841 goto trunc;
842 }
843 msgtype = *p;
844 p++;
845 length--;
846
847 /*
848 * Peek ahead to see if we start with a shift.
849 */
850 non_locking_shift = 0;
851 unshift_codeset = codeset;
852 if (length != 0) {
853 if (!ND_TTEST(*p)) {
854 if (!ndo->ndo_eflag)
855 ND_PRINT((ndo, ", "));
856 ND_PRINT((ndo, "length %u", olen));
857 goto trunc;
858 }
859 iecode = *p;
860 if (IE_IS_SHIFT(iecode)) {
861 /*
862 * It's a shift. Skip over it.
863 */
864 p++;
865 length--;
866
867 /*
868 * Get the codeset.
869 */
870 codeset = IE_SHIFT_CODESET(iecode);
871
872 /*
873 * If it's a locking shift to codeset 5,
874 * mark this as ANSI. (XXX - 5 is actually
875 * for national variants in general, not
876 * the US variant in particular, but maybe
877 * this is more American exceptionalism. :-))
878 */
879 if (IE_SHIFT_IS_LOCKING(iecode)) {
880 /*
881 * It's a locking shift.
882 */
883 if (codeset == 5) {
884 /*
885 * It's a locking shift to
886 * codeset 5, so this is
887 * T1.617 Annex D.
888 */
889 is_ansi = 1;
890 }
891 } else {
892 /*
893 * It's a non-locking shift.
894 * Remember the current codeset, so we
895 * can revert to it after the next IE.
896 */
897 non_locking_shift = 1;
898 unshift_codeset = 0;
899 }
900 }
901 }
902
903 /* printing out header part */
904 if (!ndo->ndo_eflag)
905 ND_PRINT((ndo, ", "));
906 ND_PRINT((ndo, "%s, codeset %u", is_ansi ? "ANSI" : "CCITT", codeset));
907
908 if (call_ref_length != 0) {
909 ND_TCHECK(p[0]);
910 if (call_ref_length > 1 || p[0] != 0) {
911 /*
912 * Not a dummy call reference.
913 */
914 ND_PRINT((ndo, ", Call Ref: 0x"));
915 for (i = 0; i < call_ref_length; i++)
916 ND_PRINT((ndo, "%02x", call_ref[i]));
917 }
918 }
919 if (ndo->ndo_vflag) {
920 ND_PRINT((ndo, ", %s (0x%02x), length %u",
921 tok2str(fr_q933_msg_values,
922 "unknown message", msgtype),
923 msgtype,
924 olen));
925 } else {
926 ND_PRINT((ndo, ", %s",
927 tok2str(fr_q933_msg_values,
928 "unknown message 0x%02x", msgtype)));
929 }
930
931 /* Loop through the rest of the IEs */
932 while (length != 0) {
933 /*
934 * What's the state of any non-locking shifts?
935 */
936 if (non_locking_shift == 1) {
937 /*
938 * There's a non-locking shift in effect for
939 * this IE. Count it, so we reset the codeset
940 * before the next IE.
941 */
942 non_locking_shift = 2;
943 } else if (non_locking_shift == 2) {
944 /*
945 * Unshift.
946 */
947 codeset = unshift_codeset;
948 non_locking_shift = 0;
949 }
950
951 /*
952 * Get the first octet of the IE.
953 */
954 if (!ND_TTEST(*p)) {
955 if (!ndo->ndo_vflag) {
956 ND_PRINT((ndo, ", length %u", olen));
957 }
958 goto trunc;
959 }
960 iecode = *p;
961 p++;
962 length--;
963
964 /* Single-octet IE? */
965 if (IE_IS_SINGLE_OCTET(iecode)) {
966 /*
967 * Yes. Is it a shift?
968 */
969 if (IE_IS_SHIFT(iecode)) {
970 /*
971 * Yes. Is it locking?
972 */
973 if (IE_SHIFT_IS_LOCKING(iecode)) {
974 /*
975 * Yes.
976 */
977 non_locking_shift = 0;
978 } else {
979 /*
980 * No. Remember the current
981 * codeset, so we can revert
982 * to it after the next IE.
983 */
984 non_locking_shift = 1;
985 unshift_codeset = codeset;
986 }
987
988 /*
989 * Get the codeset.
990 */
991 codeset = IE_SHIFT_CODESET(iecode);
992 }
993 } else {
994 /*
995 * No. Get the IE length.
996 */
997 if (length == 0 || !ND_TTEST(*p)) {
998 if (!ndo->ndo_vflag) {
999 ND_PRINT((ndo, ", length %u", olen));
1000 }
1001 goto trunc;
1002 }
1003 ielength = *p;
1004 p++;
1005 length--;
1006
1007 /* lets do the full IE parsing only in verbose mode
1008 * however some IEs (DLCI Status, Link Verify)
1009 * are also interesting in non-verbose mode */
1010 if (ndo->ndo_vflag) {
1011 ND_PRINT((ndo, "\n\t%s IE (0x%02x), length %u: ",
1012 tok2str(fr_q933_ie_codesets[codeset],
1013 "unknown", iecode),
1014 iecode,
1015 ielength));
1016 }
1017
1018 /* sanity checks */
1019 if (iecode == 0 || ielength == 0) {
1020 return;
1021 }
1022 if (length < ielength || !ND_TTEST2(*p, ielength)) {
1023 if (!ndo->ndo_vflag) {
1024 ND_PRINT((ndo, ", length %u", olen));
1025 }
1026 goto trunc;
1027 }
1028
1029 ie_is_known = 0;
1030 if (fr_q933_print_ie_codeset[codeset] != NULL) {
1031 ie_is_known = fr_q933_print_ie_codeset[codeset](ndo, iecode, ielength, p);
1032 }
1033
1034 if (ie_is_known) {
1035 /*
1036 * Known IE; do we want to see a hexdump
1037 * of it?
1038 */
1039 if (ndo->ndo_vflag > 1) {
1040 /* Yes. */
1041 print_unknown_data(ndo, p, "\n\t ", ielength);
1042 }
1043 } else {
1044 /*
1045 * Unknown IE; if we're printing verbosely,
1046 * print its content in hex.
1047 */
1048 if (ndo->ndo_vflag >= 1) {
1049 print_unknown_data(ndo, p, "\n\t", ielength);
1050 }
1051 }
1052
1053 length -= ielength;
1054 p += ielength;
1055 }
1056 }
1057 if (!ndo->ndo_vflag) {
1058 ND_PRINT((ndo, ", length %u", olen));
1059 }
1060 return;
1061
1062 trunc:
1063 ND_PRINT((ndo, "[|q.933]"));
1064 }
1065
1066 static int
fr_q933_print_ie_codeset_0_5(netdissect_options * ndo,u_int iecode,u_int ielength,const u_char * p)1067 fr_q933_print_ie_codeset_0_5(netdissect_options *ndo, u_int iecode,
1068 u_int ielength, const u_char *p)
1069 {
1070 u_int dlci;
1071
1072 switch (iecode) {
1073
1074 case FR_LMI_ANSI_REPORT_TYPE_IE: /* fall through */
1075 case FR_LMI_CCITT_REPORT_TYPE_IE:
1076 if (ielength < 1) {
1077 if (!ndo->ndo_vflag) {
1078 ND_PRINT((ndo, ", "));
1079 }
1080 ND_PRINT((ndo, "Invalid REPORT TYPE IE"));
1081 return 1;
1082 }
1083 if (ndo->ndo_vflag) {
1084 ND_PRINT((ndo, "%s (%u)",
1085 tok2str(fr_lmi_report_type_ie_values,"unknown",p[0]),
1086 p[0]));
1087 }
1088 return 1;
1089
1090 case FR_LMI_ANSI_LINK_VERIFY_IE: /* fall through */
1091 case FR_LMI_CCITT_LINK_VERIFY_IE:
1092 case FR_LMI_ANSI_LINK_VERIFY_IE_91:
1093 if (!ndo->ndo_vflag) {
1094 ND_PRINT((ndo, ", "));
1095 }
1096 if (ielength < 2) {
1097 ND_PRINT((ndo, "Invalid LINK VERIFY IE"));
1098 return 1;
1099 }
1100 ND_PRINT((ndo, "TX Seq: %3d, RX Seq: %3d", p[0], p[1]));
1101 return 1;
1102
1103 case FR_LMI_ANSI_PVC_STATUS_IE: /* fall through */
1104 case FR_LMI_CCITT_PVC_STATUS_IE:
1105 if (!ndo->ndo_vflag) {
1106 ND_PRINT((ndo, ", "));
1107 }
1108 /* now parse the DLCI information element. */
1109 if ((ielength < 3) ||
1110 (p[0] & 0x80) ||
1111 ((ielength == 3) && !(p[1] & 0x80)) ||
1112 ((ielength == 4) && ((p[1] & 0x80) || !(p[2] & 0x80))) ||
1113 ((ielength == 5) && ((p[1] & 0x80) || (p[2] & 0x80) ||
1114 !(p[3] & 0x80))) ||
1115 (ielength > 5) ||
1116 !(p[ielength - 1] & 0x80)) {
1117 ND_PRINT((ndo, "Invalid DLCI in PVC STATUS IE"));
1118 return 1;
1119 }
1120
1121 dlci = ((p[0] & 0x3F) << 4) | ((p[1] & 0x78) >> 3);
1122 if (ielength == 4) {
1123 dlci = (dlci << 6) | ((p[2] & 0x7E) >> 1);
1124 }
1125 else if (ielength == 5) {
1126 dlci = (dlci << 13) | (p[2] & 0x7F) | ((p[3] & 0x7E) >> 1);
1127 }
1128
1129 ND_PRINT((ndo, "DLCI %u: status %s%s", dlci,
1130 p[ielength - 1] & 0x8 ? "New, " : "",
1131 p[ielength - 1] & 0x2 ? "Active" : "Inactive"));
1132 return 1;
1133 }
1134
1135 return 0;
1136 }
1137 /*
1138 * Local Variables:
1139 * c-style: whitesmith
1140 * c-basic-offset: 8
1141 * End:
1142 */
1143