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1 office 1 /*
2 * Copyright (c) 2007-2011 Grégoire Henry, Juliusz Chroboczek
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. Neither the name of the project nor the names of its contributors
13 * may be used to endorse or promote products derived from this software
14 * without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28  
29 #define NETDISSECT_REWORKED
30 #ifdef HAVE_CONFIG_H
31 #include "config.h"
32 #endif
33  
34 #include <tcpdump-stdinc.h>
35  
36 #include <stdio.h>
37 #include <string.h>
38  
39 #include "interface.h"
40 #include "addrtoname.h"
41 #include "extract.h"
42  
43 static const char tstr[] = "[|babel]";
44  
45 static void babel_print_v2(netdissect_options *, const u_char *cp, u_int length);
46  
47 void
48 babel_print(netdissect_options *ndo,
49 const u_char *cp, u_int length)
50 {
51 ND_PRINT((ndo, "babel"));
52  
53 ND_TCHECK2(*cp, 4);
54  
55 if(cp[0] != 42) {
56 ND_PRINT((ndo, " malformed header"));
57 return;
58 } else {
59 ND_PRINT((ndo, " %d", cp[1]));
60 }
61  
62 switch(cp[1]) {
63 case 2:
64 babel_print_v2(ndo, cp, length);
65 break;
66 default:
67 ND_PRINT((ndo, " unknown version"));
68 break;
69 }
70  
71 return;
72  
73 trunc:
74 ND_PRINT((ndo, " %s", tstr));
75 return;
76 }
77  
78 /* TLVs */
79 #define MESSAGE_PAD1 0
80 #define MESSAGE_PADN 1
81 #define MESSAGE_ACK_REQ 2
82 #define MESSAGE_ACK 3
83 #define MESSAGE_HELLO 4
84 #define MESSAGE_IHU 5
85 #define MESSAGE_ROUTER_ID 6
86 #define MESSAGE_NH 7
87 #define MESSAGE_UPDATE 8
88 #define MESSAGE_REQUEST 9
89 #define MESSAGE_MH_REQUEST 10
90 #define MESSAGE_TSPC 11
91 #define MESSAGE_HMAC 12
92  
93 /* sub-TLVs */
94 #define MESSAGE_SUB_PAD1 0
95 #define MESSAGE_SUB_PADN 1
96 #define MESSAGE_SUB_DIVERSITY 2
97 #define MESSAGE_SUB_TIMESTAMP 3
98  
99 /* Diversity sub-TLV channel codes */
100 static const struct tok diversity_str[] = {
101 { 0, "reserved" },
102 { 255, "all" },
103 { 0, NULL }
104 };
105  
106 static const char *
107 format_id(const u_char *id)
108 {
109 static char buf[25];
110 snprintf(buf, 25, "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x",
111 id[0], id[1], id[2], id[3], id[4], id[5], id[6], id[7]);
112 buf[24] = '\0';
113 return buf;
114 }
115  
116 static const unsigned char v4prefix[16] =
117 {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
118  
119 static const char *
120 format_prefix(netdissect_options *ndo, const u_char *prefix, unsigned char plen)
121 {
122 static char buf[50];
123 if(plen >= 96 && memcmp(prefix, v4prefix, 12) == 0)
124 snprintf(buf, 50, "%s/%u", ipaddr_string(ndo, prefix + 12), plen - 96);
125 else
126 #ifdef INET6
127 snprintf(buf, 50, "%s/%u", ip6addr_string(ndo, prefix), plen);
128 #else
129 snprintf(buf, 50, "IPv6 addresses not supported");
130 #endif
131 buf[49] = '\0';
132 return buf;
133 }
134  
135 static const char *
136 format_address(netdissect_options *ndo, const u_char *prefix)
137 {
138 if(memcmp(prefix, v4prefix, 12) == 0)
139 return ipaddr_string(ndo, prefix + 12);
140 else
141 #ifdef INET6
142 return ip6addr_string(ndo, prefix);
143 #else
144 return "IPv6 addresses not supported";
145 #endif
146 }
147  
148 static const char *
149 format_interval(const uint16_t i)
150 {
151 static char buf[sizeof("000.00s")];
152  
153 if (i == 0)
154 return "0.0s (bogus)";
155 snprintf(buf, sizeof(buf), "%u.%02us", i / 100, i % 100);
156 return buf;
157 }
158  
159 static const char *
160 format_interval_update(const uint16_t i)
161 {
162 return i == 0xFFFF ? "infinity" : format_interval(i);
163 }
164  
165 static const char *
166 format_timestamp(const uint32_t i)
167 {
168 static char buf[sizeof("0000.000000s")];
169 snprintf(buf, sizeof(buf), "%u.%06us", i / 1000000, i % 1000000);
170 return buf;
171 }
172  
173 /* Return number of octets consumed from the input buffer (not the prefix length
174 * in bytes), or -1 for encoding error. */
175 static int
176 network_prefix(int ae, int plen, unsigned int omitted,
177 const unsigned char *p, const unsigned char *dp,
178 unsigned int len, unsigned char *p_r)
179 {
180 unsigned pb;
181 unsigned char prefix[16];
182 int consumed = 0;
183  
184 if(plen >= 0)
185 pb = (plen + 7) / 8;
186 else if(ae == 1)
187 pb = 4;
188 else
189 pb = 16;
190  
191 if(pb > 16)
192 return -1;
193  
194 memset(prefix, 0, 16);
195  
196 switch(ae) {
197 case 0: break;
198 case 1:
199 if(omitted > 4 || pb > 4 || (pb > omitted && len < pb - omitted))
200 return -1;
201 memcpy(prefix, v4prefix, 12);
202 if(omitted) {
203 if (dp == NULL) return -1;
204 memcpy(prefix, dp, 12 + omitted);
205 }
206 if(pb > omitted) {
207 memcpy(prefix + 12 + omitted, p, pb - omitted);
208 consumed = pb - omitted;
209 }
210 break;
211 case 2:
212 if(omitted > 16 || (pb > omitted && len < pb - omitted))
213 return -1;
214 if(omitted) {
215 if (dp == NULL) return -1;
216 memcpy(prefix, dp, omitted);
217 }
218 if(pb > omitted) {
219 memcpy(prefix + omitted, p, pb - omitted);
220 consumed = pb - omitted;
221 }
222 break;
223 case 3:
224 if(pb > 8 && len < pb - 8) return -1;
225 prefix[0] = 0xfe;
226 prefix[1] = 0x80;
227 if(pb > 8) {
228 memcpy(prefix + 8, p, pb - 8);
229 consumed = pb - 8;
230 }
231 break;
232 default:
233 return -1;
234 }
235  
236 memcpy(p_r, prefix, 16);
237 return consumed;
238 }
239  
240 static int
241 network_address(int ae, const unsigned char *a, unsigned int len,
242 unsigned char *a_r)
243 {
244 return network_prefix(ae, -1, 0, a, NULL, len, a_r);
245 }
246  
247 /*
248 * Sub-TLVs consume the "extra data" of Babel TLVs (see Section 4.3 of RFC6126),
249 * their encoding is similar to the encoding of TLVs, but the type namespace is
250 * different:
251 *
252 * o Type 0 stands for Pad1 sub-TLV with the same encoding as the Pad1 TLV.
253 * o Type 1 stands for PadN sub-TLV with the same encoding as the PadN TLV.
254 * o Type 2 stands for Diversity sub-TLV, which propagates diversity routing
255 * data. Its body is a variable-length sequence of 8-bit unsigned integers,
256 * each representing per-hop number of interferring radio channel for the
257 * prefix. Channel 0 is invalid and must not be used in the sub-TLV, channel
258 * 255 interferes with any other channel.
259 * o Type 3 stands for Timestamp sub-TLV, used to compute RTT between
260 * neighbours. In the case of a Hello TLV, the body stores a 32-bits
261 * timestamp, while in the case of a IHU TLV, two 32-bits timestamps are
262 * stored.
263 *
264 * Sub-TLV types 0 and 1 are valid for any TLV type, whether sub-TLV type 2 is
265 * only valid for TLV type 8 (Update). Note that within an Update TLV a missing
266 * Diversity sub-TLV is not the same as a Diversity sub-TLV with an empty body.
267 * The former would mean a lack of any claims about the interference, and the
268 * latter would state that interference is definitely absent.
269 * A type 3 sub-TLV is valid both for Hello and IHU TLVs, though the exact
270 * semantic of the sub-TLV is different in each case.
271 */
272 static void
273 subtlvs_print(netdissect_options *ndo,
274 const u_char *cp, const u_char *ep, const uint8_t tlv_type)
275 {
276 uint8_t subtype, sublen;
277 const char *sep;
278 uint32_t t1, t2;
279  
280 while (cp < ep) {
281 subtype = *cp++;
282 if(subtype == MESSAGE_SUB_PAD1) {
283 ND_PRINT((ndo, " sub-pad1"));
284 continue;
285 }
286 if(cp == ep)
287 goto corrupt;
288 sublen = *cp++;
289 if(cp + sublen > ep)
290 goto corrupt;
291  
292 switch(subtype) {
293 case MESSAGE_SUB_PADN:
294 ND_PRINT((ndo, " sub-padn"));
295 cp += sublen;
296 break;
297 case MESSAGE_SUB_DIVERSITY:
298 ND_PRINT((ndo, " sub-diversity"));
299 if (sublen == 0) {
300 ND_PRINT((ndo, " empty"));
301 break;
302 }
303 sep = " ";
304 while(sublen--) {
305 ND_PRINT((ndo, "%s%s", sep, tok2str(diversity_str, "%u", *cp++)));
306 sep = "-";
307 }
308 if(tlv_type != MESSAGE_UPDATE)
309 ND_PRINT((ndo, " (bogus)"));
310 break;
311 case MESSAGE_SUB_TIMESTAMP:
312 ND_PRINT((ndo, " sub-timestamp"));
313 if(tlv_type == MESSAGE_HELLO) {
314 if(sublen < 4)
315 goto corrupt;
316 t1 = EXTRACT_32BITS(cp);
317 ND_PRINT((ndo, " %s", format_timestamp(t1)));
318 } else if(tlv_type == MESSAGE_IHU) {
319 if(sublen < 8)
320 goto corrupt;
321 t1 = EXTRACT_32BITS(cp);
322 ND_PRINT((ndo, " %s", format_timestamp(t1)));
323 t2 = EXTRACT_32BITS(cp + 4);
324 ND_PRINT((ndo, "|%s", format_timestamp(t2)));
325 } else
326 ND_PRINT((ndo, " (bogus)"));
327 cp += sublen;
328 break;
329 default:
330 ND_PRINT((ndo, " sub-unknown-0x%02x", subtype));
331 cp += sublen;
332 } /* switch */
333 } /* while */
334 return;
335  
336 corrupt:
337 ND_PRINT((ndo, " (corrupt)"));
338 }
339  
340 #define ICHECK(i, l) \
341 if ((i) + (l) > bodylen || (i) + (l) > length) goto corrupt;
342  
343 static void
344 babel_print_v2(netdissect_options *ndo,
345 const u_char *cp, u_int length)
346 {
347 u_int i;
348 u_short bodylen;
349 u_char v4_prefix[16] =
350 {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
351 u_char v6_prefix[16] = {0};
352  
353 ND_TCHECK2(*cp, 4);
354 if (length < 4)
355 goto corrupt;
356 bodylen = EXTRACT_16BITS(cp + 2);
357 ND_PRINT((ndo, " (%u)", bodylen));
358  
359 /* Process the TLVs in the body */
360 i = 0;
361 while(i < bodylen) {
362 const u_char *message;
363 u_int type, len;
364  
365 message = cp + 4 + i;
366  
367 ND_TCHECK2(*message, 1);
368 if((type = message[0]) == MESSAGE_PAD1) {
369 ND_PRINT((ndo, ndo->ndo_vflag ? "\n\tPad 1" : " pad1"));
370 i += 1;
371 continue;
372 }
373  
374 ND_TCHECK2(*message, 2);
375 ICHECK(i, 2);
376 len = message[1];
377  
378 ND_TCHECK2(*message, 2 + len);
379 ICHECK(i, 2 + len);
380  
381 switch(type) {
382 case MESSAGE_PADN: {
383 if (!ndo->ndo_vflag)
384 ND_PRINT((ndo, " padN"));
385 else
386 ND_PRINT((ndo, "\n\tPad %d", len + 2));
387 }
388 break;
389  
390 case MESSAGE_ACK_REQ: {
391 u_short nonce, interval;
392 if (!ndo->ndo_vflag)
393 ND_PRINT((ndo, " ack-req"));
394 else {
395 ND_PRINT((ndo, "\n\tAcknowledgment Request "));
396 if(len < 6) goto corrupt;
397 nonce = EXTRACT_16BITS(message + 4);
398 interval = EXTRACT_16BITS(message + 6);
399 ND_PRINT((ndo, "%04x %s", nonce, format_interval(interval)));
400 }
401 }
402 break;
403  
404 case MESSAGE_ACK: {
405 u_short nonce;
406 if (!ndo->ndo_vflag)
407 ND_PRINT((ndo, " ack"));
408 else {
409 ND_PRINT((ndo, "\n\tAcknowledgment "));
410 if(len < 2) goto corrupt;
411 nonce = EXTRACT_16BITS(message + 2);
412 ND_PRINT((ndo, "%04x", nonce));
413 }
414 }
415 break;
416  
417 case MESSAGE_HELLO: {
418 u_short seqno, interval;
419 if (!ndo->ndo_vflag)
420 ND_PRINT((ndo, " hello"));
421 else {
422 ND_PRINT((ndo, "\n\tHello "));
423 if(len < 6) goto corrupt;
424 seqno = EXTRACT_16BITS(message + 4);
425 interval = EXTRACT_16BITS(message + 6);
426 ND_PRINT((ndo, "seqno %u interval %s", seqno, format_interval(interval)));
427 /* Extra data. */
428 if(len > 6)
429 subtlvs_print(ndo, message + 8, message + 2 + len, type);
430 }
431 }
432 break;
433  
434 case MESSAGE_IHU: {
435 unsigned short txcost, interval;
436 if (!ndo->ndo_vflag)
437 ND_PRINT((ndo, " ihu"));
438 else {
439 u_char address[16];
440 int rc;
441 ND_PRINT((ndo, "\n\tIHU "));
442 if(len < 6) goto corrupt;
443 txcost = EXTRACT_16BITS(message + 4);
444 interval = EXTRACT_16BITS(message + 6);
445 rc = network_address(message[2], message + 8, len - 6, address);
446 if(rc < 0) { ND_PRINT((ndo, "%s", tstr)); break; }
447 ND_PRINT((ndo, "%s txcost %u interval %s",
448 format_address(ndo, address), txcost, format_interval(interval)));
449 /* Extra data. */
450 if((u_int)rc < len - 6)
451 subtlvs_print(ndo, message + 8 + rc, message + 2 + len,
452 type);
453 }
454 }
455 break;
456  
457 case MESSAGE_ROUTER_ID: {
458 if (!ndo->ndo_vflag)
459 ND_PRINT((ndo, " router-id"));
460 else {
461 ND_PRINT((ndo, "\n\tRouter Id"));
462 if(len < 10) goto corrupt;
463 ND_PRINT((ndo, " %s", format_id(message + 4)));
464 }
465 }
466 break;
467  
468 case MESSAGE_NH: {
469 if (!ndo->ndo_vflag)
470 ND_PRINT((ndo, " nh"));
471 else {
472 int rc;
473 u_char nh[16];
474 ND_PRINT((ndo, "\n\tNext Hop"));
475 if(len < 2) goto corrupt;
476 rc = network_address(message[2], message + 4, len - 2, nh);
477 if(rc < 0) goto corrupt;
478 ND_PRINT((ndo, " %s", format_address(ndo, nh)));
479 }
480 }
481 break;
482  
483 case MESSAGE_UPDATE: {
484 if (!ndo->ndo_vflag) {
485 ND_PRINT((ndo, " update"));
486 if(len < 1)
487 ND_PRINT((ndo, "/truncated"));
488 else
489 ND_PRINT((ndo, "%s%s%s",
490 (message[3] & 0x80) ? "/prefix": "",
491 (message[3] & 0x40) ? "/id" : "",
492 (message[3] & 0x3f) ? "/unknown" : ""));
493 } else {
494 u_short interval, seqno, metric;
495 u_char plen;
496 int rc;
497 u_char prefix[16];
498 ND_PRINT((ndo, "\n\tUpdate"));
499 if(len < 10) goto corrupt;
500 plen = message[4] + (message[2] == 1 ? 96 : 0);
501 rc = network_prefix(message[2], message[4], message[5],
502 message + 12,
503 message[2] == 1 ? v4_prefix : v6_prefix,
504 len - 10, prefix);
505 if(rc < 0) goto corrupt;
506 interval = EXTRACT_16BITS(message + 6);
507 seqno = EXTRACT_16BITS(message + 8);
508 metric = EXTRACT_16BITS(message + 10);
509 ND_PRINT((ndo, "%s%s%s %s metric %u seqno %u interval %s",
510 (message[3] & 0x80) ? "/prefix": "",
511 (message[3] & 0x40) ? "/id" : "",
512 (message[3] & 0x3f) ? "/unknown" : "",
513 format_prefix(ndo, prefix, plen),
514 metric, seqno, format_interval_update(interval)));
515 if(message[3] & 0x80) {
516 if(message[2] == 1)
517 memcpy(v4_prefix, prefix, 16);
518 else
519 memcpy(v6_prefix, prefix, 16);
520 }
521 /* extra data? */
522 if((u_int)rc < len - 10)
523 subtlvs_print(ndo, message + 12 + rc, message + 2 + len, type);
524 }
525 }
526 break;
527  
528 case MESSAGE_REQUEST: {
529 if (!ndo->ndo_vflag)
530 ND_PRINT((ndo, " request"));
531 else {
532 int rc;
533 u_char prefix[16], plen;
534 ND_PRINT((ndo, "\n\tRequest "));
535 if(len < 2) goto corrupt;
536 plen = message[3] + (message[2] == 1 ? 96 : 0);
537 rc = network_prefix(message[2], message[3], 0,
538 message + 4, NULL, len - 2, prefix);
539 if(rc < 0) goto corrupt;
540 ND_PRINT((ndo, "for %s",
541 message[2] == 0 ? "any" : format_prefix(ndo, prefix, plen)));
542 }
543 }
544 break;
545  
546 case MESSAGE_MH_REQUEST : {
547 if (!ndo->ndo_vflag)
548 ND_PRINT((ndo, " mh-request"));
549 else {
550 int rc;
551 u_short seqno;
552 u_char prefix[16], plen;
553 ND_PRINT((ndo, "\n\tMH-Request "));
554 if(len < 14) goto corrupt;
555 seqno = EXTRACT_16BITS(message + 4);
556 rc = network_prefix(message[2], message[3], 0,
557 message + 16, NULL, len - 14, prefix);
558 if(rc < 0) goto corrupt;
559 plen = message[3] + (message[2] == 1 ? 96 : 0);
560 ND_PRINT((ndo, "(%u hops) for %s seqno %u id %s",
561 message[6], format_prefix(ndo, prefix, plen),
562 seqno, format_id(message + 8)));
563 }
564 }
565 break;
566 case MESSAGE_TSPC :
567 if (!ndo->ndo_vflag)
568 ND_PRINT((ndo, " tspc"));
569 else {
570 ND_PRINT((ndo, "\n\tTS/PC "));
571 if(len < 6) goto corrupt;
572 ND_PRINT((ndo, "timestamp %u packetcounter %u", EXTRACT_32BITS (message + 4),
573 EXTRACT_16BITS(message + 2)));
574 }
575 break;
576 case MESSAGE_HMAC : {
577 if (!ndo->ndo_vflag)
578 ND_PRINT((ndo, " hmac"));
579 else {
580 unsigned j;
581 ND_PRINT((ndo, "\n\tHMAC "));
582 if(len < 18) goto corrupt;
583 ND_PRINT((ndo, "key-id %u digest-%u ", EXTRACT_16BITS(message + 2), len - 2));
584 for (j = 0; j < len - 2; j++)
585 ND_PRINT((ndo, "%02X", message[4 + j]));
586 }
587 }
588 break;
589 default:
590 if (!ndo->ndo_vflag)
591 ND_PRINT((ndo, " unknown"));
592 else
593 ND_PRINT((ndo, "\n\tUnknown message type %d", type));
594 }
595 i += len + 2;
596 }
597 return;
598  
599 trunc:
600 ND_PRINT((ndo, " %s", tstr));
601 return;
602  
603 corrupt:
604 ND_PRINT((ndo, " (corrupt)"));
605 return;
606 }