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 #include <sys/cdefs.h>
23 #ifndef lint
24 __RCSID("$NetBSD: print-domain.c,v 1.11 2024/09/02 16:15:31 christos Exp $");
25 #endif
26
27 /* \summary: Domain Name System (DNS) printer */
28
29 #include <config.h>
30
31 #include "netdissect-stdinc.h"
32
33 #include <string.h>
34
35 #include "netdissect.h"
36 #include "addrtoname.h"
37 #include "addrtostr.h"
38 #include "extract.h"
39
40 #include "nameser.h"
41
42 static const char *ns_ops[] = {
43 "", " inv_q", " stat", " op3", " notify", " update", " op6", " op7",
44 " op8", " updateA", " updateD", " updateDA",
45 " updateM", " updateMA", " zoneInit", " zoneRef",
46 };
47
48 static const char *ns_resp[] = {
49 "", " FormErr", " ServFail", " NXDomain",
50 " NotImp", " Refused", " YXDomain", " YXRRSet",
51 " NXRRSet", " NotAuth", " NotZone", " Resp11",
52 " Resp12", " Resp13", " Resp14", " NoChange",
53 " BadVers", "Resp17", " Resp18", " Resp19",
54 " Resp20", "Resp21", " Resp22", " BadCookie",
55 };
56
57 static const char *
ns_rcode(u_int rcode)58 ns_rcode(u_int rcode) {
59 static char buf[sizeof(" Resp4095")];
60
61 if (rcode < sizeof(ns_resp)/sizeof(ns_resp[0])) {
62 return (ns_resp[rcode]);
63 }
64 snprintf(buf, sizeof(buf), " Resp%u", rcode & 0xfff);
65 return (buf);
66 }
67
68 /* skip over a domain name */
69 static const u_char *
ns_nskip(netdissect_options * ndo,const u_char * cp)70 ns_nskip(netdissect_options *ndo,
71 const u_char *cp)
72 {
73 u_char i;
74
75 if (!ND_TTEST_1(cp))
76 return (NULL);
77 i = GET_U_1(cp);
78 cp++;
79 while (i) {
80 switch (i & TYPE_MASK) {
81
82 case TYPE_INDIR:
83 return (cp + 1);
84
85 case TYPE_EDNS0: {
86 int bitlen, bytelen;
87
88 if ((i & ~TYPE_MASK) != EDNS0_ELT_BITLABEL)
89 return(NULL); /* unknown ELT */
90 if (!ND_TTEST_1(cp))
91 return (NULL);
92 if ((bitlen = GET_U_1(cp)) == 0)
93 bitlen = 256;
94 cp++;
95 bytelen = (bitlen + 7) / 8;
96 cp += bytelen;
97 }
98 break;
99
100 case TYPE_RESERVED:
101 return (NULL);
102
103 case TYPE_LABEL:
104 cp += i;
105 break;
106 }
107 if (!ND_TTEST_1(cp))
108 return (NULL);
109 i = GET_U_1(cp);
110 cp++;
111 }
112 return (cp);
113 }
114
115 static const u_char *
blabel_print(netdissect_options * ndo,const u_char * cp)116 blabel_print(netdissect_options *ndo,
117 const u_char *cp)
118 {
119 u_int bitlen, slen, b;
120 const u_char *bitp, *lim;
121 uint8_t tc;
122
123 if (!ND_TTEST_1(cp))
124 return(NULL);
125 if ((bitlen = GET_U_1(cp)) == 0)
126 bitlen = 256;
127 slen = (bitlen + 3) / 4;
128 lim = cp + 1 + slen;
129
130 /* print the bit string as a hex string */
131 ND_PRINT("\\[x");
132 for (bitp = cp + 1, b = bitlen; bitp < lim && b > 7; b -= 8, bitp++) {
133 ND_PRINT("%02x", GET_U_1(bitp));
134 }
135 if (b > 4) {
136 tc = GET_U_1(bitp);
137 bitp++;
138 ND_PRINT("%02x", tc & (0xff << (8 - b)));
139 } else if (b > 0) {
140 tc = GET_U_1(bitp);
141 bitp++;
142 ND_PRINT("%1x", ((tc >> 4) & 0x0f) & (0x0f << (4 - b)));
143 }
144 ND_PRINT("/%u]", bitlen);
145 return lim;
146 }
147
148 static int
labellen(netdissect_options * ndo,const u_char * cp)149 labellen(netdissect_options *ndo,
150 const u_char *cp)
151 {
152 u_int i;
153
154 if (!ND_TTEST_1(cp))
155 return(-1);
156 i = GET_U_1(cp);
157 switch (i & TYPE_MASK) {
158
159 case TYPE_EDNS0: {
160 u_int bitlen, elt;
161 if ((elt = (i & ~TYPE_MASK)) != EDNS0_ELT_BITLABEL) {
162 ND_PRINT("<ELT %d>", elt);
163 return(-1);
164 }
165 if (!ND_TTEST_1(cp + 1))
166 return(-1);
167 if ((bitlen = GET_U_1(cp + 1)) == 0)
168 bitlen = 256;
169 return(((bitlen + 7) / 8) + 1);
170 }
171
172 case TYPE_INDIR:
173 case TYPE_LABEL:
174 return(i);
175
176 default:
177 /*
178 * TYPE_RESERVED, but we use default to suppress compiler
179 * warnings about falling out of the switch statement.
180 */
181 ND_PRINT("<BAD LABEL TYPE>");
182 return(-1);
183 }
184 }
185
186 /* print a <domain-name> */
187 const u_char *
fqdn_print(netdissect_options * ndo,const u_char * cp,const u_char * bp)188 fqdn_print(netdissect_options *ndo,
189 const u_char *cp, const u_char *bp)
190 {
191 u_int i, l;
192 const u_char *rp = NULL;
193 int compress = 0;
194 u_int elt;
195 u_int offset, max_offset;
196 u_int name_chars = 0;
197
198 if ((l = labellen(ndo, cp)) == (u_int)-1)
199 return(NULL);
200 if (!ND_TTEST_1(cp))
201 return(NULL);
202 max_offset = (u_int)(cp - bp);
203 i = GET_U_1(cp);
204 cp++;
205 if ((i & TYPE_MASK) != TYPE_INDIR) {
206 compress = 0;
207 rp = cp + l;
208 }
209
210 if (i != 0) {
211 while (i && cp < ndo->ndo_snapend) {
212 switch (i & TYPE_MASK) {
213
214 case TYPE_INDIR:
215 if (!compress) {
216 rp = cp + 1;
217 compress = 1;
218 }
219 if (!ND_TTEST_1(cp))
220 return(NULL);
221 offset = (((i << 8) | GET_U_1(cp)) & 0x3fff);
222 /*
223 * This must move backwards in the packet.
224 * No RFC explicitly says that, but BIND's
225 * name decompression code requires it,
226 * as a way of preventing infinite loops
227 * and other bad behavior, and it's probably
228 * what was intended (compress by pointing
229 * to domain name suffixes already seen in
230 * the packet).
231 */
232 if (offset >= max_offset) {
233 ND_PRINT("<BAD PTR>");
234 return(NULL);
235 }
236 max_offset = offset;
237 cp = bp + offset;
238 if (!ND_TTEST_1(cp))
239 return(NULL);
240 i = GET_U_1(cp);
241 if ((l = labellen(ndo, cp)) == (u_int)-1)
242 return(NULL);
243 cp++;
244 continue;
245
246 case TYPE_EDNS0:
247 elt = (i & ~TYPE_MASK);
248 switch(elt) {
249 case EDNS0_ELT_BITLABEL:
250 if (blabel_print(ndo, cp) == NULL)
251 return (NULL);
252 break;
253 default:
254 /* unknown ELT */
255 ND_PRINT("<ELT %u>", elt);
256 return(NULL);
257 }
258 break;
259
260 case TYPE_RESERVED:
261 ND_PRINT("<BAD LABEL TYPE>");
262 return(NULL);
263
264 case TYPE_LABEL:
265 if (name_chars + l <= MAXCDNAME) {
266 if (nd_printn(ndo, cp, l, ndo->ndo_snapend))
267 return(NULL);
268 } else if (name_chars < MAXCDNAME) {
269 if (nd_printn(ndo, cp,
270 MAXCDNAME - name_chars, ndo->ndo_snapend))
271 return(NULL);
272 }
273 name_chars += l;
274 break;
275 }
276
277 cp += l;
278 if (name_chars <= MAXCDNAME)
279 ND_PRINT(".");
280 name_chars++;
281 if (!ND_TTEST_1(cp))
282 return(NULL);
283 i = GET_U_1(cp);
284 if ((l = labellen(ndo, cp)) == (u_int)-1)
285 return(NULL);
286 cp++;
287 if (!compress)
288 rp += l + 1;
289 }
290 if (name_chars > MAXCDNAME)
291 ND_PRINT("<DOMAIN NAME TOO LONG>");
292 } else
293 ND_PRINT(".");
294 return (rp);
295 }
296
297 /* print a <character-string> */
298 static const u_char *
ns_cprint(netdissect_options * ndo,const u_char * cp)299 ns_cprint(netdissect_options *ndo,
300 const u_char *cp)
301 {
302 u_int i;
303
304 if (!ND_TTEST_1(cp))
305 return (NULL);
306 i = GET_U_1(cp);
307 cp++;
308 if (nd_printn(ndo, cp, i, ndo->ndo_snapend))
309 return (NULL);
310 return (cp + i);
311 }
312
313 static void
print_eopt_ecs(netdissect_options * ndo,const u_char * cp,u_int data_len)314 print_eopt_ecs(netdissect_options *ndo, const u_char *cp,
315 u_int data_len)
316 {
317 u_int family, addr_bits, src_len, scope_len;
318
319 u_char padded[32];
320 char addr[INET6_ADDRSTRLEN];
321
322 /* ecs option must at least contain family, src len, and scope len */
323 if (data_len < 4) {
324 nd_print_invalid(ndo);
325 return;
326 }
327
328 family = GET_BE_U_2(cp);
329 cp += 2;
330 src_len = GET_U_1(cp);
331 cp += 1;
332 scope_len = GET_U_1(cp);
333 cp += 1;
334
335 if (family == 1)
336 addr_bits = 32;
337 else if (family == 2)
338 addr_bits = 128;
339 else {
340 nd_print_invalid(ndo);
341 return;
342 }
343
344 if (data_len - 4 > (addr_bits / 8)) {
345 nd_print_invalid(ndo);
346 return;
347 }
348 /* checks for invalid ecs scope or source length */
349 if (src_len > addr_bits || scope_len > addr_bits || ((src_len + 7) / 8) != (data_len - 4)) {
350 nd_print_invalid(ndo);
351 return;
352 }
353
354 /* pad the truncated address from ecs with zeros */
355 memset(padded, 0, sizeof(padded));
356 memcpy(padded, cp, data_len - 4);
357
358
359 if (family == 1)
360 ND_PRINT("%s/%d/%d", addrtostr(padded, addr, INET_ADDRSTRLEN),
361 src_len, scope_len);
362 else
363 ND_PRINT("%s/%d/%d", addrtostr6(padded, addr, INET6_ADDRSTRLEN),
364 src_len, scope_len);
365
366 }
367
368 extern const struct tok edns_opt2str[];
369 extern const struct tok dau_alg2str[];
370 extern const struct tok dhu_alg2str[];
371 extern const struct tok n3u_alg2str[];
372
373
374 /* print an <EDNS-option> */
375 static const u_char *
eopt_print(netdissect_options * ndo,const u_char * cp)376 eopt_print(netdissect_options *ndo,
377 const u_char *cp)
378 {
379 u_int opt, data_len, i;
380
381 if (!ND_TTEST_2(cp))
382 return (NULL);
383 opt = GET_BE_U_2(cp);
384 cp += 2;
385 ND_PRINT("%s", tok2str(edns_opt2str, "Opt%u", opt));
386 if (!ND_TTEST_2(cp))
387 return (NULL);
388 data_len = GET_BE_U_2(cp);
389 cp += 2;
390
391 ND_TCHECK_LEN(cp, data_len);
392
393 if (data_len > 0) {
394 ND_PRINT(" ");
395 switch (opt) {
396
397 case E_ECS:
398 print_eopt_ecs(ndo, cp, data_len);
399 break;
400 case E_COOKIE:
401 if (data_len < 8 || (data_len > 8 && data_len < 16) || data_len > 40)
402 nd_print_invalid(ndo);
403 else {
404 for (i = 0; i < data_len; ++i) {
405 /* split client and server cookie */
406 if (i == 8)
407 ND_PRINT(" ");
408 ND_PRINT("%02x", GET_U_1(cp + i));
409 }
410 }
411 break;
412 case E_KEEPALIVE:
413 if (data_len != 2)
414 nd_print_invalid(ndo);
415 else
416 /* keepalive is in increments of 100ms. Convert to seconds */
417 ND_PRINT("%0.1f sec", (GET_BE_U_2(cp) / 10.0));
418 break;
419 case E_EXPIRE:
420 if (data_len != 4)
421 nd_print_invalid(ndo);
422 else
423 ND_PRINT("%u sec", GET_BE_U_4(cp));
424 break;
425 case E_PADDING:
426 /* ignore contents and just print length */
427 ND_PRINT("(%u)", data_len);
428 break;
429 case E_KEYTAG:
430 if (data_len % 2 != 0)
431 nd_print_invalid(ndo);
432 else
433 for (i = 0; i < data_len; i += 2) {
434 if (i > 0)
435 ND_PRINT(" ");
436 ND_PRINT("%u", GET_BE_U_2(cp + i));
437 }
438 break;
439 case E_DAU:
440 for (i = 0; i < data_len; ++i) {
441 if (i > 0)
442 ND_PRINT(" ");
443 ND_PRINT("%s", tok2str(dau_alg2str, "Alg_%u", GET_U_1(cp + i)));
444 }
445 break;
446 case E_DHU:
447 for (i = 0; i < data_len; ++i) {
448 if (i > 0)
449 ND_PRINT(" ");
450 ND_PRINT("%s", tok2str(dhu_alg2str, "Alg_%u", GET_U_1(cp + i)));
451 }
452 break;
453 case E_N3U:
454 for (i = 0; i < data_len; ++i) {
455 if (i > 0)
456 ND_PRINT(" ");
457 ND_PRINT("%s", tok2str(n3u_alg2str, "Alg_%u", GET_U_1(cp + i)));
458 }
459 break;
460 case E_CHAIN:
461 fqdn_print(ndo, cp, cp + data_len);
462 break;
463 case E_NSID:
464 /* intentional fall-through. NSID is an undefined byte string */
465 default:
466 for (i = 0; i < data_len; ++i)
467 ND_PRINT("%02x", GET_U_1(cp + i));
468 break;
469 }
470 }
471 return (cp + data_len);
472
473 trunc:
474 return (NULL);
475
476 }
477
478
479
480 extern const struct tok ns_type2str[];
481
482 /* https://www.iana.org/assignments/dns-parameters */
483 const struct tok ns_type2str[] = {
484 { T_A, "A" }, /* RFC 1035 */
485 { T_NS, "NS" }, /* RFC 1035 */
486 { T_MD, "MD" }, /* RFC 1035 */
487 { T_MF, "MF" }, /* RFC 1035 */
488 { T_CNAME, "CNAME" }, /* RFC 1035 */
489 { T_SOA, "SOA" }, /* RFC 1035 */
490 { T_MB, "MB" }, /* RFC 1035 */
491 { T_MG, "MG" }, /* RFC 1035 */
492 { T_MR, "MR" }, /* RFC 1035 */
493 { T_NULL, "NULL" }, /* RFC 1035 */
494 { T_WKS, "WKS" }, /* RFC 1035 */
495 { T_PTR, "PTR" }, /* RFC 1035 */
496 { T_HINFO, "HINFO" }, /* RFC 1035 */
497 { T_MINFO, "MINFO" }, /* RFC 1035 */
498 { T_MX, "MX" }, /* RFC 1035 */
499 { T_TXT, "TXT" }, /* RFC 1035 */
500 { T_RP, "RP" }, /* RFC 1183 */
501 { T_AFSDB, "AFSDB" }, /* RFC 5864 */
502 { T_X25, "X25" }, /* RFC 1183 */
503 { T_ISDN, "ISDN" }, /* RFC 1183 */
504 { T_RT, "RT" }, /* RFC 1183 */
505 { T_NSAP, "NSAP" }, /* RFC 1706 */
506 { T_NSAP_PTR, "NSAP_PTR" }, /* RFC 1706 */
507 { T_SIG, "SIG" }, /* RFC 3008 */
508 { T_KEY, "KEY" }, /* RFC 3110 */
509 { T_PX, "PX" }, /* RFC 2163 */
510 { T_GPOS, "GPOS" }, /* RFC 1712 */
511 { T_AAAA, "AAAA" }, /* RFC 3596 */
512 { T_LOC, "LOC" }, /* RFC 1876 */
513 { T_NXT, "NXT" }, /* RFC 3755 */
514 { T_EID, "EID" }, /* Nimrod */
515 { T_NIMLOC, "NIMLOC" }, /* Nimrod */
516 { T_SRV, "SRV" }, /* RFC 2782 */
517 { T_ATMA, "ATMA" }, /* ATM Forum */
518 { T_NAPTR, "NAPTR" }, /* RFC 3403 */
519 { T_KX, "KX" }, /* RFC 2230 */
520 { T_CERT, "CERT" }, /* RFC 4398 */
521 { T_A6, "A6" }, /* RFC 6563 */
522 { T_DNAME, "DNAME" }, /* RFC 6672 */
523 { T_SINK, "SINK" },
524 { T_OPT, "OPT" }, /* RFC 6891 */
525 { T_APL, "APL" }, /* RFC 3123 */
526 { T_DS, "DS" }, /* RFC 4034 */
527 { T_SSHFP, "SSHFP" }, /* RFC 4255 */
528 { T_IPSECKEY, "IPSECKEY" }, /* RFC 4025 */
529 { T_RRSIG, "RRSIG" }, /* RFC 4034 */
530 { T_NSEC, "NSEC" }, /* RFC 4034 */
531 { T_DNSKEY, "DNSKEY" }, /* RFC 4034 */
532 { T_DHCID, "DHCID" }, /* RFC 4071 */
533 { T_NSEC3, "NSEC3" }, /* RFC 5155 */
534 { T_NSEC3PARAM, "NSEC3PARAM" }, /* RFC 5155 */
535 { T_TLSA, "TLSA" }, /* RFC 6698 */
536 { T_SMIMEA, "SMIMEA" }, /* RFC 8162 */
537 { T_HIP, "HIP" }, /* RFC 8005 */
538 { T_NINFO, "NINFO" },
539 { T_RKEY, "RKEY" },
540 { T_TALINK, "TALINK" },
541 { T_CDS, "CDS" }, /* RFC 7344 */
542 { T_CDNSKEY, "CDNSKEY" }, /* RFC 7344 */
543 { T_OPENPGPKEY, "OPENPGPKEY" }, /* RFC 7929 */
544 { T_CSYNC, "CSYNC" }, /* RFC 7477 */
545 { T_ZONEMD, "ZONEMD" }, /* RFC 8976 */
546 { T_SVCB, "SVCB" },
547 { T_HTTPS, "HTTPS" },
548 { T_SPF, "SPF" }, /* RFC 7208 */
549 { T_UINFO, "UINFO" },
550 { T_UID, "UID" },
551 { T_GID, "GID" },
552 { T_UNSPEC, "UNSPEC" },
553 { T_NID, "NID" }, /* RFC 6742 */
554 { T_L32, "L32" }, /* RFC 6742 */
555 { T_L64, "L64" }, /* RFC 6742 */
556 { T_LP, "LP" }, /* RFC 6742 */
557 { T_EUI48, "EUI48" }, /* RFC 7043 */
558 { T_EUI64, "EUI64" }, /* RFC 7043 */
559 { T_TKEY, "TKEY" }, /* RFC 2930 */
560 { T_TSIG, "TSIG" }, /* RFC 8945 */
561 { T_IXFR, "IXFR" }, /* RFC 1995 */
562 { T_AXFR, "AXFR" }, /* RFC 5936 */
563 { T_MAILB, "MAILB" }, /* RFC 1035 */
564 { T_MAILA, "MAILA" }, /* RFC 1035 */
565 { T_ANY, "ANY" }, /* RFC 8482 */
566 { T_URI, "URI" }, /* RFC 7553 */
567 { T_CAA, "CAA" }, /* RFC 8659 */
568 { T_AVC, "AVC" },
569 { T_DOA, "DOA" },
570 { T_AMTRELAY, "AMTRELAY" }, /* RFC 8777 */
571 { T_TA, "TA" },
572 { T_DLV, "DLV" }, /* RFC 8749 */
573 { 0, NULL }
574 };
575
576 extern const struct tok ns_class2str[];
577
578 const struct tok ns_class2str[] = {
579 { C_IN, "IN" }, /* Not used */
580 { C_CHAOS, "CHAOS" },
581 { C_HS, "HS" },
582 { C_ANY, "ANY" },
583 { 0, NULL }
584 };
585
586 const struct tok edns_opt2str[] = {
587 { E_LLQ, "LLQ" },
588 { E_UL, "UL" },
589 { E_NSID, "NSID" },
590 { E_DAU, "DAU" },
591 { E_DHU, "DHU" },
592 { E_N3U, "N3U" },
593 { E_ECS, "ECS" },
594 { E_EXPIRE, "EXPIRE" },
595 { E_COOKIE, "COOKIE" },
596 { E_KEEPALIVE, "KEEPALIVE" },
597 { E_PADDING, "PADDING" },
598 { E_CHAIN, "CHAIN" },
599 { E_KEYTAG, "KEY-TAG" },
600 { E_CLIENTTAG, "CLIENT-TAG" },
601 { E_SERVERTAG, "SERVER-TAG" },
602 { 0, NULL }
603 };
604
605 const struct tok dau_alg2str[] = {
606 { A_DELETE, "DELETE" },
607 { A_RSAMD5, "RSAMD5" },
608 { A_DH, "DH" },
609 { A_DSA, "DS" },
610 { A_RSASHA1, "RSASHA1" },
611 { A_DSA_NSEC3_SHA1, "DSA-NSEC3-SHA1" },
612 { A_RSASHA1_NSEC3_SHA1, "RSASHA1-NSEC3-SHA1" },
613 { A_RSASHA256, "RSASHA256" },
614 { A_RSASHA512, "RSASHA512" },
615 { A_ECC_GOST, "ECC-GOST" },
616 { A_ECDSAP256SHA256, "ECDSAP256SHA256" },
617 { A_ECDSAP384SHA384, "ECDSAP384SHA384" },
618 { A_ED25519, "ED25519" },
619 { A_ED448, "ED448" },
620 { A_INDIRECT, "INDIRECT" },
621 { A_PRIVATEDNS, "PRIVATEDNS" },
622 { A_PRIVATEOID, "PRIVATEOID" },
623 { 0, NULL }
624 };
625
626 const struct tok dhu_alg2str[] = {
627 { DS_SHA1, "SHA-1" },
628 { DS_SHA256,"SHA-256" },
629 { DS_GOST, "GOST_R_34.11-94" },
630 { DS_SHA384,"SHA-384" },
631 { 0, NULL }
632 };
633
634 const struct tok n3u_alg2str[] = {
635 { NSEC_SHA1,"SHA-1" },
636 { 0, NULL }
637 };
638
639 /* print a query */
640 static const u_char *
ns_qprint(netdissect_options * ndo,const u_char * cp,const u_char * bp,int is_mdns)641 ns_qprint(netdissect_options *ndo,
642 const u_char *cp, const u_char *bp, int is_mdns)
643 {
644 const u_char *np = cp;
645 u_int i, class;
646
647 cp = ns_nskip(ndo, cp);
648
649 if (cp == NULL || !ND_TTEST_4(cp))
650 return(NULL);
651
652 /* print the qtype */
653 i = GET_BE_U_2(cp);
654 cp += 2;
655 ND_PRINT(" %s", tok2str(ns_type2str, "Type%u", i));
656 /* print the qclass (if it's not IN) */
657 i = GET_BE_U_2(cp);
658 cp += 2;
659 if (is_mdns)
660 class = (i & ~C_QU);
661 else
662 class = i;
663 if (class != C_IN)
664 ND_PRINT(" %s", tok2str(ns_class2str, "(Class %u)", class));
665 if (is_mdns) {
666 ND_PRINT(i & C_QU ? " (QU)" : " (QM)");
667 }
668
669 ND_PRINT("? ");
670 cp = fqdn_print(ndo, np, bp);
671 return(cp ? cp + 4 : NULL);
672 }
673
674 /* print a reply */
675 static const u_char *
ns_rprint(netdissect_options * ndo,const u_char * cp,const u_char * bp,int is_mdns)676 ns_rprint(netdissect_options *ndo,
677 const u_char *cp, const u_char *bp, int is_mdns)
678 {
679 u_int i, class, opt_flags = 0;
680 u_short typ, len;
681 const u_char *rp;
682
683 if (ndo->ndo_vflag) {
684 ND_PRINT(" ");
685 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
686 return NULL;
687 } else
688 cp = ns_nskip(ndo, cp);
689
690 if (cp == NULL || !ND_TTEST_LEN(cp, 10))
691 return (ndo->ndo_snapend);
692
693 /* print the type/qtype */
694 typ = GET_BE_U_2(cp);
695 cp += 2;
696 /* print the class (if it's not IN and the type isn't OPT) */
697 i = GET_BE_U_2(cp);
698 cp += 2;
699 if (is_mdns)
700 class = (i & ~C_CACHE_FLUSH);
701 else
702 class = i;
703 if (class != C_IN && typ != T_OPT)
704 ND_PRINT(" %s", tok2str(ns_class2str, "(Class %u)", class));
705 if (is_mdns) {
706 if (i & C_CACHE_FLUSH)
707 ND_PRINT(" (Cache flush)");
708 }
709
710 if (typ == T_OPT) {
711 /* get opt flags */
712 cp += 2;
713 opt_flags = GET_BE_U_2(cp);
714 /* ignore rest of ttl field */
715 cp += 2;
716 } else if (ndo->ndo_vflag > 2) {
717 /* print ttl */
718 ND_PRINT(" [");
719 unsigned_relts_print(ndo, GET_BE_U_4(cp));
720 ND_PRINT("]");
721 cp += 4;
722 } else {
723 /* ignore ttl */
724 cp += 4;
725 }
726
727 len = GET_BE_U_2(cp);
728 cp += 2;
729
730 rp = cp + len;
731
732 ND_PRINT(" %s", tok2str(ns_type2str, "Type%u", typ));
733 if (rp > ndo->ndo_snapend)
734 return(NULL);
735
736 switch (typ) {
737 case T_A:
738 if (!ND_TTEST_LEN(cp, sizeof(nd_ipv4)))
739 return(NULL);
740 ND_PRINT(" %s", intoa(GET_IPV4_TO_NETWORK_ORDER(cp)));
741 break;
742
743 case T_NS:
744 case T_CNAME:
745 case T_PTR:
746 case T_DNAME:
747 ND_PRINT(" ");
748 if (fqdn_print(ndo, cp, bp) == NULL)
749 return(NULL);
750 break;
751
752 case T_SOA:
753 if (!ndo->ndo_vflag)
754 break;
755 ND_PRINT(" ");
756 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
757 return(NULL);
758 ND_PRINT(" ");
759 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
760 return(NULL);
761 if (!ND_TTEST_LEN(cp, 5 * 4))
762 return(NULL);
763 ND_PRINT(" %u", GET_BE_U_4(cp));
764 cp += 4;
765 ND_PRINT(" %u", GET_BE_U_4(cp));
766 cp += 4;
767 ND_PRINT(" %u", GET_BE_U_4(cp));
768 cp += 4;
769 ND_PRINT(" %u", GET_BE_U_4(cp));
770 cp += 4;
771 ND_PRINT(" %u", GET_BE_U_4(cp));
772 cp += 4;
773 break;
774 case T_MX:
775 ND_PRINT(" ");
776 if (!ND_TTEST_2(cp))
777 return(NULL);
778 if (fqdn_print(ndo, cp + 2, bp) == NULL)
779 return(NULL);
780 ND_PRINT(" %u", GET_BE_U_2(cp));
781 break;
782
783 case T_TXT:
784 while (cp < rp) {
785 ND_PRINT(" \"");
786 cp = ns_cprint(ndo, cp);
787 if (cp == NULL)
788 return(NULL);
789 ND_PRINT("\"");
790 }
791 break;
792
793 case T_SRV:
794 ND_PRINT(" ");
795 if (!ND_TTEST_6(cp))
796 return(NULL);
797 if (fqdn_print(ndo, cp + 6, bp) == NULL)
798 return(NULL);
799 ND_PRINT(":%u %u %u", GET_BE_U_2(cp + 4),
800 GET_BE_U_2(cp), GET_BE_U_2(cp + 2));
801 break;
802
803 case T_AAAA:
804 {
805 char ntop_buf[INET6_ADDRSTRLEN];
806
807 if (!ND_TTEST_LEN(cp, sizeof(nd_ipv6)))
808 return(NULL);
809 ND_PRINT(" %s",
810 addrtostr6(cp, ntop_buf, sizeof(ntop_buf)));
811
812 break;
813 }
814
815 case T_A6:
816 {
817 nd_ipv6 a;
818 int pbit, pbyte;
819 char ntop_buf[INET6_ADDRSTRLEN];
820
821 if (!ND_TTEST_1(cp))
822 return(NULL);
823 pbit = GET_U_1(cp);
824 pbyte = (pbit & ~7) / 8;
825 if (pbit > 128) {
826 ND_PRINT(" %u(bad plen)", pbit);
827 break;
828 } else if (pbit < 128) {
829 memset(a, 0, sizeof(a));
830 GET_CPY_BYTES(a + pbyte, cp + 1, sizeof(a) - pbyte);
831 ND_PRINT(" %u %s", pbit,
832 addrtostr6(&a, ntop_buf, sizeof(ntop_buf)));
833 }
834 if (pbit > 0) {
835 ND_PRINT(" ");
836 if (fqdn_print(ndo, cp + 1 + sizeof(a) - pbyte, bp) == NULL)
837 return(NULL);
838 }
839 break;
840 }
841
842 case T_URI:
843 if (!ND_TTEST_LEN(cp, len))
844 return(NULL);
845 if (len < 4) {
846 ND_PRINT(" len %u is too short (< 4)", len);
847 break;
848 }
849 ND_PRINT(" %u %u ", GET_BE_U_2(cp), GET_BE_U_2(cp + 2));
850 if (nd_printn(ndo, cp + 4, len - 4, ndo->ndo_snapend))
851 return(NULL);
852 break;
853
854 case T_OPT:
855 ND_PRINT(" UDPsize=%u", class);
856 if (opt_flags & 0x8000)
857 ND_PRINT(" DO");
858 if (cp < rp) {
859 ND_PRINT(" [");
860 while (cp < rp) {
861 cp = eopt_print(ndo, cp);
862 if (cp == NULL)
863 return(NULL);
864 if (cp < rp)
865 ND_PRINT(",");
866 }
867 ND_PRINT("]");
868 }
869 break;
870
871 case T_TSIG:
872 {
873 if (cp + len > ndo->ndo_snapend)
874 return(NULL);
875 if (!ndo->ndo_vflag)
876 break;
877 ND_PRINT(" ");
878 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
879 return(NULL);
880 cp += 6;
881 if (!ND_TTEST_2(cp))
882 return(NULL);
883 ND_PRINT(" fudge=%u", GET_BE_U_2(cp));
884 cp += 2;
885 if (!ND_TTEST_2(cp))
886 return(NULL);
887 ND_PRINT(" maclen=%u", GET_BE_U_2(cp));
888 cp += 2 + GET_BE_U_2(cp);
889 if (!ND_TTEST_2(cp))
890 return(NULL);
891 ND_PRINT(" origid=%u", GET_BE_U_2(cp));
892 cp += 2;
893 if (!ND_TTEST_2(cp))
894 return(NULL);
895 ND_PRINT(" error=%u", GET_BE_U_2(cp));
896 cp += 2;
897 if (!ND_TTEST_2(cp))
898 return(NULL);
899 ND_PRINT(" otherlen=%u", GET_BE_U_2(cp));
900 cp += 2;
901 }
902 }
903 return (rp); /* XXX This isn't always right */
904 }
905
906 void
domain_print(netdissect_options * ndo,const u_char * bp,u_int length,int over_tcp,int is_mdns)907 domain_print(netdissect_options *ndo,
908 const u_char *bp, u_int length, int over_tcp, int is_mdns)
909 {
910 const dns_header_t *np;
911 uint16_t flags, rcode, rdlen, type;
912 u_int qdcount, ancount, nscount, arcount;
913 u_int i;
914 const u_char *cp;
915 uint16_t b2;
916
917 ndo->ndo_protocol = "domain";
918
919 if (over_tcp) {
920 /*
921 * The message is prefixed with a two byte length field
922 * which gives the message length, excluding the two byte
923 * length field. (RFC 1035 - 4.2.2. TCP usage)
924 */
925 if (length < 2) {
926 ND_PRINT(" [DNS over TCP: length %u < 2]", length);
927 nd_print_invalid(ndo);
928 return;
929 } else {
930 length -= 2; /* excluding the two byte length field */
931 if (GET_BE_U_2(bp) != length) {
932 ND_PRINT(" [prefix length(%u) != length(%u)]",
933 GET_BE_U_2(bp), length);
934 nd_print_invalid(ndo);
935 return;
936 } else {
937 bp += 2;
938 /* in over TCP case, we need to prepend a space
939 * (not needed in over UDP case)
940 */
941 ND_PRINT(" ");
942 }
943 }
944 }
945
946 np = (const dns_header_t *)bp;
947
948 if(length < sizeof(*np)) {
949 nd_print_protocol(ndo);
950 ND_PRINT(" [length %u < %zu]", length, sizeof(*np));
951 nd_print_invalid(ndo);
952 return;
953 }
954
955 ND_TCHECK_SIZE(np);
956 flags = GET_BE_U_2(np->flags);
957 /* get the byte-order right */
958 qdcount = GET_BE_U_2(np->qdcount);
959 ancount = GET_BE_U_2(np->ancount);
960 nscount = GET_BE_U_2(np->nscount);
961 arcount = GET_BE_U_2(np->arcount);
962
963 /* find the opt record to extract extended rcode */
964 cp = (const u_char *)(np + 1);
965 rcode = DNS_RCODE(flags);
966 for (i = 0; i < qdcount; i++) {
967 if ((cp = ns_nskip(ndo, cp)) == NULL)
968 goto print;
969 cp += 4; /* skip QTYPE and QCLASS */
970 if (cp >= ndo->ndo_snapend)
971 goto print;
972 }
973 for (i = 0; i < ancount + nscount; i++) {
974 if ((cp = ns_nskip(ndo, cp)) == NULL)
975 goto print;
976 cp += 8; /* skip TYPE, CLASS and TTL */
977 if (cp + 2 > ndo->ndo_snapend)
978 goto print;
979 rdlen = GET_BE_U_2(cp);
980 cp += 2 + rdlen;
981 if (cp >= ndo->ndo_snapend)
982 goto print;
983 }
984 for (i = 0; i < arcount; i++) {
985 if ((cp = ns_nskip(ndo, cp)) == NULL)
986 goto print;
987 if (cp + 2 > ndo->ndo_snapend)
988 goto print;
989 type = GET_BE_U_2(cp);
990 cp += 4; /* skip TYPE and CLASS */
991 if (cp + 1 > ndo->ndo_snapend)
992 goto print;
993 if (type == T_OPT) {
994 rcode |= (GET_U_1(cp) << 4);
995 goto print;
996 }
997 cp += 4;
998 if (cp + 2 > ndo->ndo_snapend)
999 goto print;
1000 rdlen = GET_BE_U_2(cp);
1001 cp += 2 + rdlen;
1002 if (cp >= ndo->ndo_snapend)
1003 goto print;
1004 }
1005
1006 print:
1007 if (DNS_QR(flags)) {
1008 /* this is a response */
1009 ND_PRINT("%u%s%s%s%s%s%s",
1010 GET_BE_U_2(np->id),
1011 ns_ops[DNS_OPCODE(flags)],
1012 ns_rcode(rcode),
1013 DNS_AA(flags)? "*" : "",
1014 DNS_RA(flags)? "" : "-",
1015 DNS_TC(flags)? "|" : "",
1016 DNS_AD(flags)? "$" : "");
1017
1018 if (qdcount != 1)
1019 ND_PRINT(" [%uq]", qdcount);
1020 /* Print QUESTION section on -vv */
1021 cp = (const u_char *)(np + 1);
1022 for (i = 0; i < qdcount; i++) {
1023 if (i != 0)
1024 ND_PRINT(",");
1025 if (ndo->ndo_vflag > 1) {
1026 ND_PRINT(" q:");
1027 if ((cp = ns_qprint(ndo, cp, bp, is_mdns)) == NULL)
1028 goto trunc;
1029 } else {
1030 if ((cp = ns_nskip(ndo, cp)) == NULL)
1031 goto trunc;
1032 cp += 4; /* skip QTYPE and QCLASS */
1033 }
1034 }
1035 ND_PRINT(" %u/%u/%u", ancount, nscount, arcount);
1036 if (ancount) {
1037 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1038 goto trunc;
1039 ancount--;
1040 while (cp < ndo->ndo_snapend && ancount) {
1041 ND_PRINT(",");
1042 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1043 goto trunc;
1044 ancount--;
1045 }
1046 }
1047 if (ancount)
1048 goto trunc;
1049 /* Print NS and AR sections on -vv */
1050 if (ndo->ndo_vflag > 1) {
1051 if (cp < ndo->ndo_snapend && nscount) {
1052 ND_PRINT(" ns:");
1053 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1054 goto trunc;
1055 nscount--;
1056 while (cp < ndo->ndo_snapend && nscount) {
1057 ND_PRINT(",");
1058 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1059 goto trunc;
1060 nscount--;
1061 }
1062 }
1063 if (nscount)
1064 goto trunc;
1065 if (cp < ndo->ndo_snapend && arcount) {
1066 ND_PRINT(" ar:");
1067 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1068 goto trunc;
1069 arcount--;
1070 while (cp < ndo->ndo_snapend && arcount) {
1071 ND_PRINT(",");
1072 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1073 goto trunc;
1074 arcount--;
1075 }
1076 }
1077 if (arcount)
1078 goto trunc;
1079 }
1080 } else {
1081 /* this is a request */
1082 ND_PRINT("%u%s%s%s", GET_BE_U_2(np->id),
1083 ns_ops[DNS_OPCODE(flags)],
1084 DNS_RD(flags) ? "+" : "",
1085 DNS_CD(flags) ? "%" : "");
1086
1087 /* any weirdness? */
1088 b2 = GET_BE_U_2(((const u_short *)np) + 1);
1089 if (b2 & 0x6cf)
1090 ND_PRINT(" [b2&3=0x%x]", b2);
1091
1092 if (DNS_OPCODE(flags) == IQUERY) {
1093 if (qdcount)
1094 ND_PRINT(" [%uq]", qdcount);
1095 if (ancount != 1)
1096 ND_PRINT(" [%ua]", ancount);
1097 } else {
1098 if (ancount)
1099 ND_PRINT(" [%ua]", ancount);
1100 if (qdcount != 1)
1101 ND_PRINT(" [%uq]", qdcount);
1102 }
1103 if (nscount)
1104 ND_PRINT(" [%un]", nscount);
1105 if (arcount)
1106 ND_PRINT(" [%uau]", arcount);
1107
1108 cp = (const u_char *)(np + 1);
1109 if (qdcount) {
1110 cp = ns_qprint(ndo, cp, (const u_char *)np, is_mdns);
1111 if (!cp)
1112 goto trunc;
1113 qdcount--;
1114 while (cp < ndo->ndo_snapend && qdcount) {
1115 cp = ns_qprint(ndo, (const u_char *)cp,
1116 (const u_char *)np,
1117 is_mdns);
1118 if (!cp)
1119 goto trunc;
1120 qdcount--;
1121 }
1122 }
1123 if (qdcount)
1124 goto trunc;
1125
1126 /* Print remaining sections on -vv */
1127 if (ndo->ndo_vflag > 1) {
1128 if (ancount) {
1129 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1130 goto trunc;
1131 ancount--;
1132 while (cp < ndo->ndo_snapend && ancount) {
1133 ND_PRINT(",");
1134 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1135 goto trunc;
1136 ancount--;
1137 }
1138 }
1139 if (ancount)
1140 goto trunc;
1141 if (cp < ndo->ndo_snapend && nscount) {
1142 ND_PRINT(" ns:");
1143 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1144 goto trunc;
1145 nscount--;
1146 while (cp < ndo->ndo_snapend && nscount) {
1147 ND_PRINT(",");
1148 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1149 goto trunc;
1150 nscount--;
1151 }
1152 }
1153 if (nscount > 0)
1154 goto trunc;
1155 if (cp < ndo->ndo_snapend && arcount) {
1156 ND_PRINT(" ar:");
1157 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1158 goto trunc;
1159 arcount--;
1160 while (cp < ndo->ndo_snapend && arcount) {
1161 ND_PRINT(",");
1162 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1163 goto trunc;
1164 arcount--;
1165 }
1166 }
1167 if (arcount)
1168 goto trunc;
1169 }
1170 }
1171 ND_PRINT(" (%u)", length);
1172 return;
1173
1174 trunc:
1175 nd_print_trunc(ndo);
1176 }
1177