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1 /*
2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 */
21
22 /* \summary: Domain Name System (DNS) printer */
23
24 #ifdef HAVE_CONFIG_H
25 #include <config.h>
26 #endif
27
28 #include "netdissect-stdinc.h"
29
30 #include <string.h>
31
32 #include "netdissect.h"
33 #include "addrtoname.h"
34 #include "addrtostr.h"
35 #include "extract.h"
36
37 #include "nameser.h"
38
39 static const char *ns_ops[] = {
40 "", " inv_q", " stat", " op3", " notify", " update", " op6", " op7",
41 " op8", " updateA", " updateD", " updateDA",
42 " updateM", " updateMA", " zoneInit", " zoneRef",
43 };
44
45 static const char *ns_resp[] = {
46 "", " FormErr", " ServFail", " NXDomain",
47 " NotImp", " Refused", " YXDomain", " YXRRSet",
48 " NXRRSet", " NotAuth", " NotZone", " Resp11",
49 " Resp12", " Resp13", " Resp14", " NoChange",
50 " BadVers", "Resp17", " Resp18", " Resp19",
51 " Resp20", "Resp21", " Resp22", " BadCookie",
52 };
53
54 static const char *
55 ns_rcode(u_int rcode) {
56 static char buf[sizeof(" Resp4095")];
57
58 if (rcode < sizeof(ns_resp)/sizeof(ns_resp[0])) {
59 return (ns_resp[rcode]);
60 }
61 snprintf(buf, sizeof(buf), " Resp%u", rcode & 0xfff);
62 return (buf);
63 }
64
65 /* skip over a domain name */
66 static const u_char *
67 ns_nskip(netdissect_options *ndo,
68 const u_char *cp)
69 {
70 u_char i;
71
72 if (!ND_TTEST_1(cp))
73 return (NULL);
74 i = GET_U_1(cp);
75 cp++;
76 while (i) {
77 switch (i & TYPE_MASK) {
78
79 case TYPE_INDIR:
80 return (cp + 1);
81
82 case TYPE_EDNS0: {
83 int bitlen, bytelen;
84
85 if ((i & ~TYPE_MASK) != EDNS0_ELT_BITLABEL)
86 return(NULL); /* unknown ELT */
87 if (!ND_TTEST_1(cp))
88 return (NULL);
89 if ((bitlen = GET_U_1(cp)) == 0)
90 bitlen = 256;
91 cp++;
92 bytelen = (bitlen + 7) / 8;
93 cp += bytelen;
94 }
95 break;
96
97 case TYPE_RESERVED:
98 return (NULL);
99
100 case TYPE_LABEL:
101 cp += i;
102 break;
103 }
104 if (!ND_TTEST_1(cp))
105 return (NULL);
106 i = GET_U_1(cp);
107 cp++;
108 }
109 return (cp);
110 }
111
112 static const u_char *
113 blabel_print(netdissect_options *ndo,
114 const u_char *cp)
115 {
116 u_int bitlen, slen, b;
117 const u_char *bitp, *lim;
118 uint8_t tc;
119
120 if (!ND_TTEST_1(cp))
121 return(NULL);
122 if ((bitlen = GET_U_1(cp)) == 0)
123 bitlen = 256;
124 slen = (bitlen + 3) / 4;
125 lim = cp + 1 + slen;
126
127 /* print the bit string as a hex string */
128 ND_PRINT("\\[x");
129 for (bitp = cp + 1, b = bitlen; bitp < lim && b > 7; b -= 8, bitp++) {
130 ND_PRINT("%02x", GET_U_1(bitp));
131 }
132 if (b > 4) {
133 tc = GET_U_1(bitp);
134 bitp++;
135 ND_PRINT("%02x", tc & (0xff << (8 - b)));
136 } else if (b > 0) {
137 tc = GET_U_1(bitp);
138 bitp++;
139 ND_PRINT("%1x", ((tc >> 4) & 0x0f) & (0x0f << (4 - b)));
140 }
141 ND_PRINT("/%u]", bitlen);
142 return lim;
143 }
144
145 static int
146 labellen(netdissect_options *ndo,
147 const u_char *cp)
148 {
149 u_int i;
150
151 if (!ND_TTEST_1(cp))
152 return(-1);
153 i = GET_U_1(cp);
154 switch (i & TYPE_MASK) {
155
156 case TYPE_EDNS0: {
157 u_int bitlen, elt;
158 if ((elt = (i & ~TYPE_MASK)) != EDNS0_ELT_BITLABEL) {
159 ND_PRINT("<ELT %d>", elt);
160 return(-1);
161 }
162 if (!ND_TTEST_1(cp + 1))
163 return(-1);
164 if ((bitlen = GET_U_1(cp + 1)) == 0)
165 bitlen = 256;
166 return(((bitlen + 7) / 8) + 1);
167 }
168
169 case TYPE_INDIR:
170 case TYPE_LABEL:
171 return(i);
172
173 default:
174 /*
175 * TYPE_RESERVED, but we use default to suppress compiler
176 * warnings about falling out of the switch statement.
177 */
178 ND_PRINT("<BAD LABEL TYPE>");
179 return(-1);
180 }
181 }
182
183 /* print a <domain-name> */
184 const u_char *
185 fqdn_print(netdissect_options *ndo,
186 const u_char *cp, const u_char *bp)
187 {
188 u_int i, l;
189 const u_char *rp = NULL;
190 int compress = 0;
191 u_int elt;
192 u_int offset, max_offset;
193 u_int name_chars = 0;
194
195 if ((l = labellen(ndo, cp)) == (u_int)-1)
196 return(NULL);
197 if (!ND_TTEST_1(cp))
198 return(NULL);
199 max_offset = (u_int)(cp - bp);
200 i = GET_U_1(cp);
201 cp++;
202 if ((i & TYPE_MASK) != TYPE_INDIR) {
203 compress = 0;
204 rp = cp + l;
205 }
206
207 if (i != 0) {
208 while (i && cp < ndo->ndo_snapend) {
209 switch (i & TYPE_MASK) {
210
211 case TYPE_INDIR:
212 if (!compress) {
213 rp = cp + 1;
214 compress = 1;
215 }
216 if (!ND_TTEST_1(cp))
217 return(NULL);
218 offset = (((i << 8) | GET_U_1(cp)) & 0x3fff);
219 /*
220 * This must move backwards in the packet.
221 * No RFC explicitly says that, but BIND's
222 * name decompression code requires it,
223 * as a way of preventing infinite loops
224 * and other bad behavior, and it's probably
225 * what was intended (compress by pointing
226 * to domain name suffixes already seen in
227 * the packet).
228 */
229 if (offset >= max_offset) {
230 ND_PRINT("<BAD PTR>");
231 return(NULL);
232 }
233 max_offset = offset;
234 cp = bp + offset;
235 if (!ND_TTEST_1(cp))
236 return(NULL);
237 i = GET_U_1(cp);
238 if ((l = labellen(ndo, cp)) == (u_int)-1)
239 return(NULL);
240 cp++;
241 continue;
242
243 case TYPE_EDNS0:
244 elt = (i & ~TYPE_MASK);
245 switch(elt) {
246 case EDNS0_ELT_BITLABEL:
247 if (blabel_print(ndo, cp) == NULL)
248 return (NULL);
249 break;
250 default:
251 /* unknown ELT */
252 ND_PRINT("<ELT %u>", elt);
253 return(NULL);
254 }
255 break;
256
257 case TYPE_RESERVED:
258 ND_PRINT("<BAD LABEL TYPE>");
259 return(NULL);
260
261 case TYPE_LABEL:
262 if (name_chars + l <= MAXCDNAME) {
263 if (nd_printn(ndo, cp, l, ndo->ndo_snapend))
264 return(NULL);
265 } else if (name_chars < MAXCDNAME) {
266 if (nd_printn(ndo, cp,
267 MAXCDNAME - name_chars, ndo->ndo_snapend))
268 return(NULL);
269 }
270 name_chars += l;
271 break;
272 }
273
274 cp += l;
275 if (name_chars <= MAXCDNAME)
276 ND_PRINT(".");
277 name_chars++;
278 if (!ND_TTEST_1(cp))
279 return(NULL);
280 i = GET_U_1(cp);
281 if ((l = labellen(ndo, cp)) == (u_int)-1)
282 return(NULL);
283 cp++;
284 if (!compress)
285 rp += l + 1;
286 }
287 if (name_chars > MAXCDNAME)
288 ND_PRINT("<DOMAIN NAME TOO LONG>");
289 } else
290 ND_PRINT(".");
291 return (rp);
292 }
293
294 /* print a <character-string> */
295 static const u_char *
296 ns_cprint(netdissect_options *ndo,
297 const u_char *cp)
298 {
299 u_int i;
300
301 if (!ND_TTEST_1(cp))
302 return (NULL);
303 i = GET_U_1(cp);
304 cp++;
305 if (nd_printn(ndo, cp, i, ndo->ndo_snapend))
306 return (NULL);
307 return (cp + i);
308 }
309
310 static void
311 print_eopt_ecs(netdissect_options *ndo, const u_char *cp,
312 u_int data_len)
313 {
314 u_int family, addr_bits, src_len, scope_len;
315
316 u_char padded[32];
317 char addr[INET6_ADDRSTRLEN];
318
319 /* ecs option must at least contain family, src len, and scope len */
320 if (data_len < 4) {
321 nd_print_invalid(ndo);
322 return;
323 }
324
325 family = GET_BE_U_2(cp);
326 cp += 2;
327 src_len = GET_U_1(cp);
328 cp += 1;
329 scope_len = GET_U_1(cp);
330 cp += 1;
331
332 if (family == 1)
333 addr_bits = 32;
334 else if (family == 2)
335 addr_bits = 128;
336 else {
337 nd_print_invalid(ndo);
338 return;
339 }
340
341 if (data_len - 4 > (addr_bits / 8)) {
342 nd_print_invalid(ndo);
343 return;
344 }
345 /* checks for invalid ecs scope or source length */
346 if (src_len > addr_bits || scope_len > addr_bits || ((src_len + 7) / 8) != (data_len - 4)) {
347 nd_print_invalid(ndo);
348 return;
349 }
350
351 /* pad the truncated address from ecs with zeros */
352 memset(padded, 0, sizeof(padded));
353 memcpy(padded, cp, data_len - 4);
354
355
356 if (family == 1)
357 ND_PRINT("%s/%d/%d", addrtostr(padded, addr, INET_ADDRSTRLEN),
358 src_len, scope_len);
359 else
360 ND_PRINT("%s/%d/%d", addrtostr6(padded, addr, INET6_ADDRSTRLEN),
361 src_len, scope_len);
362
363 }
364
365 extern const struct tok edns_opt2str[];
366 extern const struct tok dau_alg2str[];
367 extern const struct tok dhu_alg2str[];
368 extern const struct tok n3u_alg2str[];
369
370
371 /* print an <EDNS-option> */
372 static const u_char *
373 eopt_print(netdissect_options *ndo,
374 const u_char *cp)
375 {
376 u_int opt, data_len, i;
377
378 if (!ND_TTEST_2(cp))
379 return (NULL);
380 opt = GET_BE_U_2(cp);
381 cp += 2;
382 ND_PRINT("%s", tok2str(edns_opt2str, "Opt%u", opt));
383 if (!ND_TTEST_2(cp))
384 return (NULL);
385 data_len = GET_BE_U_2(cp);
386 cp += 2;
387
388 ND_TCHECK_LEN(cp, data_len);
389
390 if (data_len > 0) {
391 ND_PRINT(" ");
392 switch (opt) {
393
394 case E_ECS:
395 print_eopt_ecs(ndo, cp, data_len);
396 break;
397 case E_COOKIE:
398 if (data_len < 8 || (data_len > 8 && data_len < 16) || data_len > 40)
399 nd_print_invalid(ndo);
400 else {
401 for (i = 0; i < data_len; ++i) {
402 /* split client and server cookie */
403 if (i == 8)
404 ND_PRINT(" ");
405 ND_PRINT("%02x", GET_U_1(cp + i));
406 }
407 }
408 break;
409 case E_KEEPALIVE:
410 if (data_len != 2)
411 nd_print_invalid(ndo);
412 else
413 /* keepalive is in increments of 100ms. Convert to seconds */
414 ND_PRINT("%0.1f sec", (GET_BE_U_2(cp) / 10.0));
415 break;
416 case E_EXPIRE:
417 if (data_len != 4)
418 nd_print_invalid(ndo);
419 else
420 ND_PRINT("%u sec", GET_BE_U_4(cp));
421 break;
422 case E_PADDING:
423 /* ignore contents and just print length */
424 ND_PRINT("(%u)", data_len);
425 break;
426 case E_KEYTAG:
427 if (data_len % 2 != 0)
428 nd_print_invalid(ndo);
429 else
430 for (i = 0; i < data_len; i += 2) {
431 if (i > 0)
432 ND_PRINT(" ");
433 ND_PRINT("%u", GET_BE_U_2(cp + i));
434 }
435 break;
436 case E_DAU:
437 for (i = 0; i < data_len; ++i) {
438 if (i > 0)
439 ND_PRINT(" ");
440 ND_PRINT("%s", tok2str(dau_alg2str, "Alg_%u", GET_U_1(cp + i)));
441 }
442 break;
443 case E_DHU:
444 for (i = 0; i < data_len; ++i) {
445 if (i > 0)
446 ND_PRINT(" ");
447 ND_PRINT("%s", tok2str(dhu_alg2str, "Alg_%u", GET_U_1(cp + i)));
448 }
449 break;
450 case E_N3U:
451 for (i = 0; i < data_len; ++i) {
452 if (i > 0)
453 ND_PRINT(" ");
454 ND_PRINT("%s", tok2str(n3u_alg2str, "Alg_%u", GET_U_1(cp + i)));
455 }
456 break;
457 case E_CHAIN:
458 fqdn_print(ndo, cp, cp + data_len);
459 break;
460 case E_NSID:
461 /* intentional fall-through. NSID is an undefined byte string */
462 default:
463 for (i = 0; i < data_len; ++i)
464 ND_PRINT("%02x", GET_U_1(cp + i));
465 break;
466 }
467 }
468 return (cp + data_len);
469
470 trunc:
471 return (NULL);
472
473 }
474
475
476
477 extern const struct tok ns_type2str[];
478
479 /* https://www.iana.org/assignments/dns-parameters */
480 const struct tok ns_type2str[] = {
481 { T_A, "A" }, /* RFC 1035 */
482 { T_NS, "NS" }, /* RFC 1035 */
483 { T_MD, "MD" }, /* RFC 1035 */
484 { T_MF, "MF" }, /* RFC 1035 */
485 { T_CNAME, "CNAME" }, /* RFC 1035 */
486 { T_SOA, "SOA" }, /* RFC 1035 */
487 { T_MB, "MB" }, /* RFC 1035 */
488 { T_MG, "MG" }, /* RFC 1035 */
489 { T_MR, "MR" }, /* RFC 1035 */
490 { T_NULL, "NULL" }, /* RFC 1035 */
491 { T_WKS, "WKS" }, /* RFC 1035 */
492 { T_PTR, "PTR" }, /* RFC 1035 */
493 { T_HINFO, "HINFO" }, /* RFC 1035 */
494 { T_MINFO, "MINFO" }, /* RFC 1035 */
495 { T_MX, "MX" }, /* RFC 1035 */
496 { T_TXT, "TXT" }, /* RFC 1035 */
497 { T_RP, "RP" }, /* RFC 1183 */
498 { T_AFSDB, "AFSDB" }, /* RFC 1183 */
499 { T_X25, "X25" }, /* RFC 1183 */
500 { T_ISDN, "ISDN" }, /* RFC 1183 */
501 { T_RT, "RT" }, /* RFC 1183 */
502 { T_NSAP, "NSAP" }, /* RFC 1706 */
503 { T_NSAP_PTR, "NSAP_PTR" },
504 { T_SIG, "SIG" }, /* RFC 2535 */
505 { T_KEY, "KEY" }, /* RFC 2535 */
506 { T_PX, "PX" }, /* RFC 2163 */
507 { T_GPOS, "GPOS" }, /* RFC 1712 */
508 { T_AAAA, "AAAA" }, /* RFC 1886 */
509 { T_LOC, "LOC" }, /* RFC 1876 */
510 { T_NXT, "NXT" }, /* RFC 2535 */
511 { T_EID, "EID" }, /* Nimrod */
512 { T_NIMLOC, "NIMLOC" }, /* Nimrod */
513 { T_SRV, "SRV" }, /* RFC 2782 */
514 { T_ATMA, "ATMA" }, /* ATM Forum */
515 { T_NAPTR, "NAPTR" }, /* RFC 2168, RFC 2915 */
516 { T_KX, "KX" }, /* RFC 2230 */
517 { T_CERT, "CERT" }, /* RFC 2538 */
518 { T_A6, "A6" }, /* RFC 2874 */
519 { T_DNAME, "DNAME" }, /* RFC 2672 */
520 { T_SINK, "SINK" },
521 { T_OPT, "OPT" }, /* RFC 2671 */
522 { T_APL, "APL" }, /* RFC 3123 */
523 { T_DS, "DS" }, /* RFC 4034 */
524 { T_SSHFP, "SSHFP" }, /* RFC 4255 */
525 { T_IPSECKEY, "IPSECKEY" }, /* RFC 4025 */
526 { T_RRSIG, "RRSIG" }, /* RFC 4034 */
527 { T_NSEC, "NSEC" }, /* RFC 4034 */
528 { T_DNSKEY, "DNSKEY" }, /* RFC 4034 */
529 { T_SPF, "SPF" }, /* RFC-schlitt-spf-classic-02.txt */
530 { T_UINFO, "UINFO" },
531 { T_UID, "UID" },
532 { T_GID, "GID" },
533 { T_UNSPEC, "UNSPEC" },
534 { T_UNSPECA, "UNSPECA" },
535 { T_TKEY, "TKEY" }, /* RFC 2930 */
536 { T_TSIG, "TSIG" }, /* RFC 2845 */
537 { T_IXFR, "IXFR" }, /* RFC 1995 */
538 { T_AXFR, "AXFR" }, /* RFC 1035 */
539 { T_MAILB, "MAILB" }, /* RFC 1035 */
540 { T_MAILA, "MAILA" }, /* RFC 1035 */
541 { T_ANY, "ANY" },
542 { T_URI, "URI" }, /* RFC 7553 */
543 { 0, NULL }
544 };
545
546 extern const struct tok ns_class2str[];
547
548 const struct tok ns_class2str[] = {
549 { C_IN, "IN" }, /* Not used */
550 { C_CHAOS, "CHAOS" },
551 { C_HS, "HS" },
552 { C_ANY, "ANY" },
553 { 0, NULL }
554 };
555
556 const struct tok edns_opt2str[] = {
557 { E_LLQ, "LLQ" },
558 { E_UL, "UL" },
559 { E_NSID, "NSID" },
560 { E_DAU, "DAU" },
561 { E_DHU, "DHU" },
562 { E_N3U, "N3U" },
563 { E_ECS, "ECS" },
564 { E_EXPIRE, "EXPIRE" },
565 { E_COOKIE, "COOKIE" },
566 { E_KEEPALIVE, "KEEPALIVE" },
567 { E_PADDING, "PADDING" },
568 { E_CHAIN, "CHAIN" },
569 { E_KEYTAG, "KEY-TAG" },
570 { E_CLIENTTAG, "CLIENT-TAG" },
571 { E_SERVERTAG, "SERVER-TAG" },
572 { 0, NULL }
573 };
574
575 const struct tok dau_alg2str[] = {
576 { A_DELETE, "DELETE" },
577 { A_RSAMD5, "RSAMD5" },
578 { A_DH, "DH" },
579 { A_DSA, "DS" },
580 { A_RSASHA1, "RSASHA1" },
581 { A_DSA_NSEC3_SHA1, "DSA-NSEC3-SHA1" },
582 { A_RSASHA1_NSEC3_SHA1, "RSASHA1-NSEC3-SHA1" },
583 { A_RSASHA256, "RSASHA256" },
584 { A_RSASHA512, "RSASHA512" },
585 { A_ECC_GOST, "ECC-GOST" },
586 { A_ECDSAP256SHA256, "ECDSAP256SHA256" },
587 { A_ECDSAP384SHA384, "ECDSAP384SHA384" },
588 { A_ED25519, "ED25519" },
589 { A_ED448, "ED448" },
590 { A_INDIRECT, "INDIRECT" },
591 { A_PRIVATEDNS, "PRIVATEDNS" },
592 { A_PRIVATEOID, "PRIVATEOID" },
593 { 0, NULL }
594 };
595
596 const struct tok dhu_alg2str[] = {
597 { DS_SHA1, "SHA-1" },
598 { DS_SHA256,"SHA-256" },
599 { DS_GOST, "GOST_R_34.11-94" },
600 { DS_SHA384,"SHA-384" },
601 { 0, NULL }
602 };
603
604 const struct tok n3u_alg2str[] = {
605 { NSEC_SHA1,"SHA-1" },
606 { 0, NULL }
607 };
608
609 /* print a query */
610 static const u_char *
611 ns_qprint(netdissect_options *ndo,
612 const u_char *cp, const u_char *bp, int is_mdns)
613 {
614 const u_char *np = cp;
615 u_int i, class;
616
617 cp = ns_nskip(ndo, cp);
618
619 if (cp == NULL || !ND_TTEST_4(cp))
620 return(NULL);
621
622 /* print the qtype */
623 i = GET_BE_U_2(cp);
624 cp += 2;
625 ND_PRINT(" %s", tok2str(ns_type2str, "Type%u", i));
626 /* print the qclass (if it's not IN) */
627 i = GET_BE_U_2(cp);
628 cp += 2;
629 if (is_mdns)
630 class = (i & ~C_QU);
631 else
632 class = i;
633 if (class != C_IN)
634 ND_PRINT(" %s", tok2str(ns_class2str, "(Class %u)", class));
635 if (is_mdns) {
636 ND_PRINT(i & C_QU ? " (QU)" : " (QM)");
637 }
638
639 ND_PRINT("? ");
640 cp = fqdn_print(ndo, np, bp);
641 return(cp ? cp + 4 : NULL);
642 }
643
644 /* print a reply */
645 static const u_char *
646 ns_rprint(netdissect_options *ndo,
647 const u_char *cp, const u_char *bp, int is_mdns)
648 {
649 u_int i, class, opt_flags = 0;
650 u_short typ, len;
651 const u_char *rp;
652
653 if (ndo->ndo_vflag) {
654 ND_PRINT(" ");
655 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
656 return NULL;
657 } else
658 cp = ns_nskip(ndo, cp);
659
660 if (cp == NULL || !ND_TTEST_LEN(cp, 10))
661 return (ndo->ndo_snapend);
662
663 /* print the type/qtype */
664 typ = GET_BE_U_2(cp);
665 cp += 2;
666 /* print the class (if it's not IN and the type isn't OPT) */
667 i = GET_BE_U_2(cp);
668 cp += 2;
669 if (is_mdns)
670 class = (i & ~C_CACHE_FLUSH);
671 else
672 class = i;
673 if (class != C_IN && typ != T_OPT)
674 ND_PRINT(" %s", tok2str(ns_class2str, "(Class %u)", class));
675 if (is_mdns) {
676 if (i & C_CACHE_FLUSH)
677 ND_PRINT(" (Cache flush)");
678 }
679
680 if (typ == T_OPT) {
681 /* get opt flags */
682 cp += 2;
683 opt_flags = GET_BE_U_2(cp);
684 /* ignore rest of ttl field */
685 cp += 2;
686 } else if (ndo->ndo_vflag > 2) {
687 /* print ttl */
688 ND_PRINT(" [");
689 unsigned_relts_print(ndo, GET_BE_U_4(cp));
690 ND_PRINT("]");
691 cp += 4;
692 } else {
693 /* ignore ttl */
694 cp += 4;
695 }
696
697 len = GET_BE_U_2(cp);
698 cp += 2;
699
700 rp = cp + len;
701
702 ND_PRINT(" %s", tok2str(ns_type2str, "Type%u", typ));
703 if (rp > ndo->ndo_snapend)
704 return(NULL);
705
706 switch (typ) {
707 case T_A:
708 if (!ND_TTEST_LEN(cp, sizeof(nd_ipv4)))
709 return(NULL);
710 ND_PRINT(" %s", intoa(GET_IPV4_TO_NETWORK_ORDER(cp)));
711 break;
712
713 case T_NS:
714 case T_CNAME:
715 case T_PTR:
716 case T_DNAME:
717 ND_PRINT(" ");
718 if (fqdn_print(ndo, cp, bp) == NULL)
719 return(NULL);
720 break;
721
722 case T_SOA:
723 if (!ndo->ndo_vflag)
724 break;
725 ND_PRINT(" ");
726 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
727 return(NULL);
728 ND_PRINT(" ");
729 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
730 return(NULL);
731 if (!ND_TTEST_LEN(cp, 5 * 4))
732 return(NULL);
733 ND_PRINT(" %u", GET_BE_U_4(cp));
734 cp += 4;
735 ND_PRINT(" %u", GET_BE_U_4(cp));
736 cp += 4;
737 ND_PRINT(" %u", GET_BE_U_4(cp));
738 cp += 4;
739 ND_PRINT(" %u", GET_BE_U_4(cp));
740 cp += 4;
741 ND_PRINT(" %u", GET_BE_U_4(cp));
742 cp += 4;
743 break;
744 case T_MX:
745 ND_PRINT(" ");
746 if (!ND_TTEST_2(cp))
747 return(NULL);
748 if (fqdn_print(ndo, cp + 2, bp) == NULL)
749 return(NULL);
750 ND_PRINT(" %u", GET_BE_U_2(cp));
751 break;
752
753 case T_TXT:
754 while (cp < rp) {
755 ND_PRINT(" \"");
756 cp = ns_cprint(ndo, cp);
757 if (cp == NULL)
758 return(NULL);
759 ND_PRINT("\"");
760 }
761 break;
762
763 case T_SRV:
764 ND_PRINT(" ");
765 if (!ND_TTEST_6(cp))
766 return(NULL);
767 if (fqdn_print(ndo, cp + 6, bp) == NULL)
768 return(NULL);
769 ND_PRINT(":%u %u %u", GET_BE_U_2(cp + 4),
770 GET_BE_U_2(cp), GET_BE_U_2(cp + 2));
771 break;
772
773 case T_AAAA:
774 {
775 char ntop_buf[INET6_ADDRSTRLEN];
776
777 if (!ND_TTEST_LEN(cp, sizeof(nd_ipv6)))
778 return(NULL);
779 ND_PRINT(" %s",
780 addrtostr6(cp, ntop_buf, sizeof(ntop_buf)));
781
782 break;
783 }
784
785 case T_A6:
786 {
787 nd_ipv6 a;
788 int pbit, pbyte;
789 char ntop_buf[INET6_ADDRSTRLEN];
790
791 if (!ND_TTEST_1(cp))
792 return(NULL);
793 pbit = GET_U_1(cp);
794 pbyte = (pbit & ~7) / 8;
795 if (pbit > 128) {
796 ND_PRINT(" %u(bad plen)", pbit);
797 break;
798 } else if (pbit < 128) {
799 if (!ND_TTEST_LEN(cp + 1, sizeof(a) - pbyte))
800 return(NULL);
801 memset(a, 0, sizeof(a));
802 memcpy(a + pbyte, cp + 1, sizeof(a) - pbyte);
803 ND_PRINT(" %u %s", pbit,
804 addrtostr6(&a, ntop_buf, sizeof(ntop_buf)));
805 }
806 if (pbit > 0) {
807 ND_PRINT(" ");
808 if (fqdn_print(ndo, cp + 1 + sizeof(a) - pbyte, bp) == NULL)
809 return(NULL);
810 }
811 break;
812 }
813
814 case T_URI:
815 if (!ND_TTEST_LEN(cp, len))
816 return(NULL);
817 ND_PRINT(" %u %u ", GET_BE_U_2(cp), GET_BE_U_2(cp + 2));
818 if (nd_printn(ndo, cp + 4, len - 4, ndo->ndo_snapend))
819 return(NULL);
820 break;
821
822 case T_OPT:
823 ND_PRINT(" UDPsize=%u", class);
824 if (opt_flags & 0x8000)
825 ND_PRINT(" DO");
826 if (cp < rp) {
827 ND_PRINT(" [");
828 while (cp < rp) {
829 cp = eopt_print(ndo, cp);
830 if (cp == NULL)
831 return(NULL);
832 if (cp < rp)
833 ND_PRINT(",");
834 }
835 ND_PRINT("]");
836 }
837 break;
838
839 case T_UNSPECA: /* One long string */
840 if (!ND_TTEST_LEN(cp, len))
841 return(NULL);
842 if (nd_printn(ndo, cp, len, ndo->ndo_snapend))
843 return(NULL);
844 break;
845
846 case T_TSIG:
847 {
848 if (cp + len > ndo->ndo_snapend)
849 return(NULL);
850 if (!ndo->ndo_vflag)
851 break;
852 ND_PRINT(" ");
853 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
854 return(NULL);
855 cp += 6;
856 if (!ND_TTEST_2(cp))
857 return(NULL);
858 ND_PRINT(" fudge=%u", GET_BE_U_2(cp));
859 cp += 2;
860 if (!ND_TTEST_2(cp))
861 return(NULL);
862 ND_PRINT(" maclen=%u", GET_BE_U_2(cp));
863 cp += 2 + GET_BE_U_2(cp);
864 if (!ND_TTEST_2(cp))
865 return(NULL);
866 ND_PRINT(" origid=%u", GET_BE_U_2(cp));
867 cp += 2;
868 if (!ND_TTEST_2(cp))
869 return(NULL);
870 ND_PRINT(" error=%u", GET_BE_U_2(cp));
871 cp += 2;
872 if (!ND_TTEST_2(cp))
873 return(NULL);
874 ND_PRINT(" otherlen=%u", GET_BE_U_2(cp));
875 cp += 2;
876 }
877 }
878 return (rp); /* XXX This isn't always right */
879 }
880
881 void
882 domain_print(netdissect_options *ndo,
883 const u_char *bp, u_int length, int over_tcp, int is_mdns)
884 {
885 const dns_header_t *np;
886 uint16_t flags, rcode, rdlen, type;
887 u_int qdcount, ancount, nscount, arcount;
888 u_int i;
889 const u_char *cp;
890 uint16_t b2;
891
892 ndo->ndo_protocol = "domain";
893
894 if (over_tcp) {
895 /*
896 * The message is prefixed with a two byte length field
897 * which gives the message length, excluding the two byte
898 * length field. (RFC 1035 - 4.2.2. TCP usage)
899 */
900 if (length < 2) {
901 ND_PRINT(" [DNS over TCP: length %u < 2]", length);
902 nd_print_invalid(ndo);
903 return;
904 } else {
905 length -= 2; /* excluding the two byte length field */
906 if (GET_BE_U_2(bp) != length) {
907 ND_PRINT(" [prefix length(%u) != length(%u)]",
908 GET_BE_U_2(bp), length);
909 nd_print_invalid(ndo);
910 return;
911 } else {
912 bp += 2;
913 /* in over TCP case, we need to prepend a space
914 * (not needed in over UDP case)
915 */
916 ND_PRINT(" ");
917 }
918 }
919 }
920
921 np = (const dns_header_t *)bp;
922
923 if(length < sizeof(*np)) {
924 nd_print_protocol(ndo);
925 ND_PRINT(" [length %u < %zu]", length, sizeof(*np));
926 nd_print_invalid(ndo);
927 return;
928 }
929
930 ND_TCHECK_SIZE(np);
931 flags = GET_BE_U_2(np->flags);
932 /* get the byte-order right */
933 qdcount = GET_BE_U_2(np->qdcount);
934 ancount = GET_BE_U_2(np->ancount);
935 nscount = GET_BE_U_2(np->nscount);
936 arcount = GET_BE_U_2(np->arcount);
937
938 /* find the opt record to extract extended rcode */
939 cp = (const u_char *)(np + 1);
940 rcode = DNS_RCODE(flags);
941 for (i = 0; i < qdcount; i++) {
942 if ((cp = ns_nskip(ndo, cp)) == NULL)
943 goto print;
944 cp += 4; /* skip QTYPE and QCLASS */
945 if (cp >= ndo->ndo_snapend)
946 goto print;
947 }
948 for (i = 0; i < ancount + nscount; i++) {
949 if ((cp = ns_nskip(ndo, cp)) == NULL)
950 goto print;
951 cp += 8; /* skip TYPE, CLASS and TTL */
952 if (cp + 2 > ndo->ndo_snapend)
953 goto print;
954 rdlen = GET_BE_U_2(cp);
955 cp += 2 + rdlen;
956 if (cp >= ndo->ndo_snapend)
957 goto print;
958 }
959 for (i = 0; i < arcount; i++) {
960 if ((cp = ns_nskip(ndo, cp)) == NULL)
961 goto print;
962 if (cp + 2 > ndo->ndo_snapend)
963 goto print;
964 type = GET_BE_U_2(cp);
965 cp += 4; /* skip TYPE and CLASS */
966 if (cp + 1 > ndo->ndo_snapend)
967 goto print;
968 if (type == T_OPT) {
969 rcode |= (GET_U_1(cp) << 4);
970 goto print;
971 }
972 cp += 4;
973 if (cp + 2 > ndo->ndo_snapend)
974 goto print;
975 rdlen = GET_BE_U_2(cp);
976 cp += 2 + rdlen;
977 if (cp >= ndo->ndo_snapend)
978 goto print;
979 }
980
981 print:
982 if (DNS_QR(flags)) {
983 /* this is a response */
984 ND_PRINT("%u%s%s%s%s%s%s",
985 GET_BE_U_2(np->id),
986 ns_ops[DNS_OPCODE(flags)],
987 ns_rcode(rcode),
988 DNS_AA(flags)? "*" : "",
989 DNS_RA(flags)? "" : "-",
990 DNS_TC(flags)? "|" : "",
991 DNS_AD(flags)? "$" : "");
992
993 if (qdcount != 1)
994 ND_PRINT(" [%uq]", qdcount);
995 /* Print QUESTION section on -vv */
996 cp = (const u_char *)(np + 1);
997 for (i = 0; i < qdcount; i++) {
998 if (i != 0)
999 ND_PRINT(",");
1000 if (ndo->ndo_vflag > 1) {
1001 ND_PRINT(" q:");
1002 if ((cp = ns_qprint(ndo, cp, bp, is_mdns)) == NULL)
1003 goto trunc;
1004 } else {
1005 if ((cp = ns_nskip(ndo, cp)) == NULL)
1006 goto trunc;
1007 cp += 4; /* skip QTYPE and QCLASS */
1008 }
1009 }
1010 ND_PRINT(" %u/%u/%u", ancount, nscount, arcount);
1011 if (ancount) {
1012 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1013 goto trunc;
1014 ancount--;
1015 while (cp < ndo->ndo_snapend && ancount) {
1016 ND_PRINT(",");
1017 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1018 goto trunc;
1019 ancount--;
1020 }
1021 }
1022 if (ancount)
1023 goto trunc;
1024 /* Print NS and AR sections on -vv */
1025 if (ndo->ndo_vflag > 1) {
1026 if (cp < ndo->ndo_snapend && nscount) {
1027 ND_PRINT(" ns:");
1028 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1029 goto trunc;
1030 nscount--;
1031 while (cp < ndo->ndo_snapend && nscount) {
1032 ND_PRINT(",");
1033 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1034 goto trunc;
1035 nscount--;
1036 }
1037 }
1038 if (nscount)
1039 goto trunc;
1040 if (cp < ndo->ndo_snapend && arcount) {
1041 ND_PRINT(" ar:");
1042 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1043 goto trunc;
1044 arcount--;
1045 while (cp < ndo->ndo_snapend && arcount) {
1046 ND_PRINT(",");
1047 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1048 goto trunc;
1049 arcount--;
1050 }
1051 }
1052 if (arcount)
1053 goto trunc;
1054 }
1055 }
1056 else {
1057 /* this is a request */
1058 ND_PRINT("%u%s%s%s", GET_BE_U_2(np->id),
1059 ns_ops[DNS_OPCODE(flags)],
1060 DNS_RD(flags) ? "+" : "",
1061 DNS_CD(flags) ? "%" : "");
1062
1063 /* any weirdness? */
1064 b2 = GET_BE_U_2(((const u_short *)np) + 1);
1065 if (b2 & 0x6cf)
1066 ND_PRINT(" [b2&3=0x%x]", b2);
1067
1068 if (DNS_OPCODE(flags) == IQUERY) {
1069 if (qdcount)
1070 ND_PRINT(" [%uq]", qdcount);
1071 if (ancount != 1)
1072 ND_PRINT(" [%ua]", ancount);
1073 }
1074 else {
1075 if (ancount)
1076 ND_PRINT(" [%ua]", ancount);
1077 if (qdcount != 1)
1078 ND_PRINT(" [%uq]", qdcount);
1079 }
1080 if (nscount)
1081 ND_PRINT(" [%un]", nscount);
1082 if (arcount)
1083 ND_PRINT(" [%uau]", arcount);
1084
1085 cp = (const u_char *)(np + 1);
1086 if (qdcount) {
1087 cp = ns_qprint(ndo, cp, (const u_char *)np, is_mdns);
1088 if (!cp)
1089 goto trunc;
1090 qdcount--;
1091 while (cp < ndo->ndo_snapend && qdcount) {
1092 cp = ns_qprint(ndo, (const u_char *)cp,
1093 (const u_char *)np,
1094 is_mdns);
1095 if (!cp)
1096 goto trunc;
1097 qdcount--;
1098 }
1099 }
1100 if (qdcount)
1101 goto trunc;
1102
1103 /* Print remaining sections on -vv */
1104 if (ndo->ndo_vflag > 1) {
1105 if (ancount) {
1106 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1107 goto trunc;
1108 ancount--;
1109 while (cp < ndo->ndo_snapend && ancount) {
1110 ND_PRINT(",");
1111 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1112 goto trunc;
1113 ancount--;
1114 }
1115 }
1116 if (ancount)
1117 goto trunc;
1118 if (cp < ndo->ndo_snapend && nscount) {
1119 ND_PRINT(" ns:");
1120 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1121 goto trunc;
1122 nscount--;
1123 while (cp < ndo->ndo_snapend && nscount) {
1124 ND_PRINT(",");
1125 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1126 goto trunc;
1127 nscount--;
1128 }
1129 }
1130 if (nscount > 0)
1131 goto trunc;
1132 if (cp < ndo->ndo_snapend && arcount) {
1133 ND_PRINT(" ar:");
1134 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1135 goto trunc;
1136 arcount--;
1137 while (cp < ndo->ndo_snapend && arcount) {
1138 ND_PRINT(",");
1139 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1140 goto trunc;
1141 arcount--;
1142 }
1143 }
1144 if (arcount)
1145 goto trunc;
1146 }
1147 }
1148 ND_PRINT(" (%u)", length);
1149 return;
1150
1151 trunc:
1152 nd_print_trunc(ndo);
1153 }
[mirror] the TCPdump network dissector