]> The Tcpdump Group git mirrors - tcpdump/blob - print-domain.c
projects / tcpdump / blob


d2275a5e2a30efdff142b6185108f6874e8a9b27
[tcpdump] / print-domain.c
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 5864 */
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" }, /* RFC 1706 */
504 { T_SIG, "SIG" }, /* RFC 3008 */
505 { T_KEY, "KEY" }, /* RFC 3110 */
506 { T_PX, "PX" }, /* RFC 2163 */
507 { T_GPOS, "GPOS" }, /* RFC 1712 */
508 { T_AAAA, "AAAA" }, /* RFC 3596 */
509 { T_LOC, "LOC" }, /* RFC 1876 */
510 { T_NXT, "NXT" }, /* RFC 3755 */
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 3403 */
516 { T_KX, "KX" }, /* RFC 2230 */
517 { T_CERT, "CERT" }, /* RFC 4398 */
518 { T_A6, "A6" }, /* RFC 6563 */
519 { T_DNAME, "DNAME" }, /* RFC 6672 */
520 { T_SINK, "SINK" },
521 { T_OPT, "OPT" }, /* RFC 6891 */
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_DHCID, "DHCID" }, /* RFC 4071 */
530 { T_NSEC3, "NSEC3" }, /* RFC 5155 */
531 { T_NSEC3PARAM, "NSEC3PARAM" }, /* RFC 5155 */
532 { T_TLSA, "TLSA" }, /* RFC 6698 */
533 { T_SMIMEA, "SMIMEA" }, /* RFC 8162 */
534 { T_HIP, "HIP" }, /* RFC 8005 */
535 { T_NINFO, "NINFO" },
536 { T_RKEY, "RKEY" },
537 { T_TALINK, "TALINK" },
538 { T_CDS, "CDS" }, /* RFC 7344 */
539 { T_CDNSKEY, "CDNSKEY" }, /* RFC 7344 */
540 { T_OPENPGPKEY, "OPENPGPKEY" }, /* RFC 7929 */
541 { T_CSYNC, "CSYNC" }, /* RFC 7477 */
542 { T_ZONEMD, "ZONEMD" }, /* RFC 8976 */
543 { T_SVCB, "SVCB" },
544 { T_HTTPS, "HTTPS" },
545 { T_SPF, "SPF" }, /* RFC 7208 */
546 { T_UINFO, "UINFO" },
547 { T_UID, "UID" },
548 { T_GID, "GID" },
549 { T_UNSPEC, "UNSPEC" },
550 { T_NID, "NID" }, /* RFC 6742 */
551 { T_L32, "L32" }, /* RFC 6742 */
552 { T_L64, "L64" }, /* RFC 6742 */
553 { T_LP, "LP" }, /* RFC 6742 */
554 { T_EUI48, "EUI48" }, /* RFC 7043 */
555 { T_EUI64, "EUI64" }, /* RFC 7043 */
556 { T_TKEY, "TKEY" }, /* RFC 2930 */
557 { T_TSIG, "TSIG" }, /* RFC 8945 */
558 { T_IXFR, "IXFR" }, /* RFC 1995 */
559 { T_AXFR, "AXFR" }, /* RFC 5936 */
560 { T_MAILB, "MAILB" }, /* RFC 1035 */
561 { T_MAILA, "MAILA" }, /* RFC 1035 */
562 { T_ANY, "ANY" }, /* RFC 8482 */
563 { T_URI, "URI" }, /* RFC 7553 */
564 { T_CAA, "CAA" }, /* RFC 8659 */
565 { T_AVC, "AVC" },
566 { T_DOA, "DOA" },
567 { T_AMTRELAY, "AMTRELAY" }, /* RFC 8777 */
568 { T_TA, "TA" },
569 { T_DLV, "DLV" }, /* RFC 8749 */
570 { 0, NULL }
571 };
572
573 extern const struct tok ns_class2str[];
574
575 const struct tok ns_class2str[] = {
576 { C_IN, "IN" }, /* Not used */
577 { C_CHAOS, "CHAOS" },
578 { C_HS, "HS" },
579 { C_ANY, "ANY" },
580 { 0, NULL }
581 };
582
583 const struct tok edns_opt2str[] = {
584 { E_LLQ, "LLQ" },
585 { E_UL, "UL" },
586 { E_NSID, "NSID" },
587 { E_DAU, "DAU" },
588 { E_DHU, "DHU" },
589 { E_N3U, "N3U" },
590 { E_ECS, "ECS" },
591 { E_EXPIRE, "EXPIRE" },
592 { E_COOKIE, "COOKIE" },
593 { E_KEEPALIVE, "KEEPALIVE" },
594 { E_PADDING, "PADDING" },
595 { E_CHAIN, "CHAIN" },
596 { E_KEYTAG, "KEY-TAG" },
597 { E_CLIENTTAG, "CLIENT-TAG" },
598 { E_SERVERTAG, "SERVER-TAG" },
599 { 0, NULL }
600 };
601
602 const struct tok dau_alg2str[] = {
603 { A_DELETE, "DELETE" },
604 { A_RSAMD5, "RSAMD5" },
605 { A_DH, "DH" },
606 { A_DSA, "DS" },
607 { A_RSASHA1, "RSASHA1" },
608 { A_DSA_NSEC3_SHA1, "DSA-NSEC3-SHA1" },
609 { A_RSASHA1_NSEC3_SHA1, "RSASHA1-NSEC3-SHA1" },
610 { A_RSASHA256, "RSASHA256" },
611 { A_RSASHA512, "RSASHA512" },
612 { A_ECC_GOST, "ECC-GOST" },
613 { A_ECDSAP256SHA256, "ECDSAP256SHA256" },
614 { A_ECDSAP384SHA384, "ECDSAP384SHA384" },
615 { A_ED25519, "ED25519" },
616 { A_ED448, "ED448" },
617 { A_INDIRECT, "INDIRECT" },
618 { A_PRIVATEDNS, "PRIVATEDNS" },
619 { A_PRIVATEOID, "PRIVATEOID" },
620 { 0, NULL }
621 };
622
623 const struct tok dhu_alg2str[] = {
624 { DS_SHA1, "SHA-1" },
625 { DS_SHA256,"SHA-256" },
626 { DS_GOST, "GOST_R_34.11-94" },
627 { DS_SHA384,"SHA-384" },
628 { 0, NULL }
629 };
630
631 const struct tok n3u_alg2str[] = {
632 { NSEC_SHA1,"SHA-1" },
633 { 0, NULL }
634 };
635
636 /* print a query */
637 static const u_char *
638 ns_qprint(netdissect_options *ndo,
639 const u_char *cp, const u_char *bp, int is_mdns)
640 {
641 const u_char *np = cp;
642 u_int i, class;
643
644 cp = ns_nskip(ndo, cp);
645
646 if (cp == NULL || !ND_TTEST_4(cp))
647 return(NULL);
648
649 /* print the qtype */
650 i = GET_BE_U_2(cp);
651 cp += 2;
652 ND_PRINT(" %s", tok2str(ns_type2str, "Type%u", i));
653 /* print the qclass (if it's not IN) */
654 i = GET_BE_U_2(cp);
655 cp += 2;
656 if (is_mdns)
657 class = (i & ~C_QU);
658 else
659 class = i;
660 if (class != C_IN)
661 ND_PRINT(" %s", tok2str(ns_class2str, "(Class %u)", class));
662 if (is_mdns) {
663 ND_PRINT(i & C_QU ? " (QU)" : " (QM)");
664 }
665
666 ND_PRINT("? ");
667 cp = fqdn_print(ndo, np, bp);
668 return(cp ? cp + 4 : NULL);
669 }
670
671 /* print a reply */
672 static const u_char *
673 ns_rprint(netdissect_options *ndo,
674 const u_char *cp, const u_char *bp, int is_mdns)
675 {
676 u_int i, class, opt_flags = 0;
677 u_short typ, len;
678 const u_char *rp;
679
680 if (ndo->ndo_vflag) {
681 ND_PRINT(" ");
682 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
683 return NULL;
684 } else
685 cp = ns_nskip(ndo, cp);
686
687 if (cp == NULL || !ND_TTEST_LEN(cp, 10))
688 return (ndo->ndo_snapend);
689
690 /* print the type/qtype */
691 typ = GET_BE_U_2(cp);
692 cp += 2;
693 /* print the class (if it's not IN and the type isn't OPT) */
694 i = GET_BE_U_2(cp);
695 cp += 2;
696 if (is_mdns)
697 class = (i & ~C_CACHE_FLUSH);
698 else
699 class = i;
700 if (class != C_IN && typ != T_OPT)
701 ND_PRINT(" %s", tok2str(ns_class2str, "(Class %u)", class));
702 if (is_mdns) {
703 if (i & C_CACHE_FLUSH)
704 ND_PRINT(" (Cache flush)");
705 }
706
707 if (typ == T_OPT) {
708 /* get opt flags */
709 cp += 2;
710 opt_flags = GET_BE_U_2(cp);
711 /* ignore rest of ttl field */
712 cp += 2;
713 } else if (ndo->ndo_vflag > 2) {
714 /* print ttl */
715 ND_PRINT(" [");
716 unsigned_relts_print(ndo, GET_BE_U_4(cp));
717 ND_PRINT("]");
718 cp += 4;
719 } else {
720 /* ignore ttl */
721 cp += 4;
722 }
723
724 len = GET_BE_U_2(cp);
725 cp += 2;
726
727 rp = cp + len;
728
729 ND_PRINT(" %s", tok2str(ns_type2str, "Type%u", typ));
730 if (rp > ndo->ndo_snapend)
731 return(NULL);
732
733 switch (typ) {
734 case T_A:
735 if (!ND_TTEST_LEN(cp, sizeof(nd_ipv4)))
736 return(NULL);
737 ND_PRINT(" %s", intoa(GET_IPV4_TO_NETWORK_ORDER(cp)));
738 break;
739
740 case T_NS:
741 case T_CNAME:
742 case T_PTR:
743 case T_DNAME:
744 ND_PRINT(" ");
745 if (fqdn_print(ndo, cp, bp) == NULL)
746 return(NULL);
747 break;
748
749 case T_SOA:
750 if (!ndo->ndo_vflag)
751 break;
752 ND_PRINT(" ");
753 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
754 return(NULL);
755 ND_PRINT(" ");
756 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
757 return(NULL);
758 if (!ND_TTEST_LEN(cp, 5 * 4))
759 return(NULL);
760 ND_PRINT(" %u", GET_BE_U_4(cp));
761 cp += 4;
762 ND_PRINT(" %u", GET_BE_U_4(cp));
763 cp += 4;
764 ND_PRINT(" %u", GET_BE_U_4(cp));
765 cp += 4;
766 ND_PRINT(" %u", GET_BE_U_4(cp));
767 cp += 4;
768 ND_PRINT(" %u", GET_BE_U_4(cp));
769 cp += 4;
770 break;
771 case T_MX:
772 ND_PRINT(" ");
773 if (!ND_TTEST_2(cp))
774 return(NULL);
775 if (fqdn_print(ndo, cp + 2, bp) == NULL)
776 return(NULL);
777 ND_PRINT(" %u", GET_BE_U_2(cp));
778 break;
779
780 case T_TXT:
781 while (cp < rp) {
782 ND_PRINT(" \"");
783 cp = ns_cprint(ndo, cp);
784 if (cp == NULL)
785 return(NULL);
786 ND_PRINT("\"");
787 }
788 break;
789
790 case T_SRV:
791 ND_PRINT(" ");
792 if (!ND_TTEST_6(cp))
793 return(NULL);
794 if (fqdn_print(ndo, cp + 6, bp) == NULL)
795 return(NULL);
796 ND_PRINT(":%u %u %u", GET_BE_U_2(cp + 4),
797 GET_BE_U_2(cp), GET_BE_U_2(cp + 2));
798 break;
799
800 case T_AAAA:
801 {
802 char ntop_buf[INET6_ADDRSTRLEN];
803
804 if (!ND_TTEST_LEN(cp, sizeof(nd_ipv6)))
805 return(NULL);
806 ND_PRINT(" %s",
807 addrtostr6(cp, ntop_buf, sizeof(ntop_buf)));
808
809 break;
810 }
811
812 case T_A6:
813 {
814 nd_ipv6 a;
815 int pbit, pbyte;
816 char ntop_buf[INET6_ADDRSTRLEN];
817
818 if (!ND_TTEST_1(cp))
819 return(NULL);
820 pbit = GET_U_1(cp);
821 pbyte = (pbit & ~7) / 8;
822 if (pbit > 128) {
823 ND_PRINT(" %u(bad plen)", pbit);
824 break;
825 } else if (pbit < 128) {
826 memset(a, 0, sizeof(a));
827 GET_CPY_BYTES(a + pbyte, cp + 1, sizeof(a) - pbyte);
828 ND_PRINT(" %u %s", pbit,
829 addrtostr6(&a, ntop_buf, sizeof(ntop_buf)));
830 }
831 if (pbit > 0) {
832 ND_PRINT(" ");
833 if (fqdn_print(ndo, cp + 1 + sizeof(a) - pbyte, bp) == NULL)
834 return(NULL);
835 }
836 break;
837 }
838
839 case T_URI:
840 if (!ND_TTEST_LEN(cp, len))
841 return(NULL);
842 ND_PRINT(" %u %u ", GET_BE_U_2(cp), GET_BE_U_2(cp + 2));
843 if (nd_printn(ndo, cp + 4, len - 4, ndo->ndo_snapend))
844 return(NULL);
845 break;
846
847 case T_OPT:
848 ND_PRINT(" UDPsize=%u", class);
849 if (opt_flags & 0x8000)
850 ND_PRINT(" DO");
851 if (cp < rp) {
852 ND_PRINT(" [");
853 while (cp < rp) {
854 cp = eopt_print(ndo, cp);
855 if (cp == NULL)
856 return(NULL);
857 if (cp < rp)
858 ND_PRINT(",");
859 }
860 ND_PRINT("]");
861 }
862 break;
863
864 case T_TSIG:
865 {
866 if (cp + len > ndo->ndo_snapend)
867 return(NULL);
868 if (!ndo->ndo_vflag)
869 break;
870 ND_PRINT(" ");
871 if ((cp = fqdn_print(ndo, cp, bp)) == NULL)
872 return(NULL);
873 cp += 6;
874 if (!ND_TTEST_2(cp))
875 return(NULL);
876 ND_PRINT(" fudge=%u", GET_BE_U_2(cp));
877 cp += 2;
878 if (!ND_TTEST_2(cp))
879 return(NULL);
880 ND_PRINT(" maclen=%u", GET_BE_U_2(cp));
881 cp += 2 + GET_BE_U_2(cp);
882 if (!ND_TTEST_2(cp))
883 return(NULL);
884 ND_PRINT(" origid=%u", GET_BE_U_2(cp));
885 cp += 2;
886 if (!ND_TTEST_2(cp))
887 return(NULL);
888 ND_PRINT(" error=%u", GET_BE_U_2(cp));
889 cp += 2;
890 if (!ND_TTEST_2(cp))
891 return(NULL);
892 ND_PRINT(" otherlen=%u", GET_BE_U_2(cp));
893 cp += 2;
894 }
895 }
896 return (rp); /* XXX This isn't always right */
897 }
898
899 void
900 domain_print(netdissect_options *ndo,
901 const u_char *bp, u_int length, int over_tcp, int is_mdns)
902 {
903 const dns_header_t *np;
904 uint16_t flags, rcode, rdlen, type;
905 u_int qdcount, ancount, nscount, arcount;
906 u_int i;
907 const u_char *cp;
908 uint16_t b2;
909
910 ndo->ndo_protocol = "domain";
911
912 if (over_tcp) {
913 /*
914 * The message is prefixed with a two byte length field
915 * which gives the message length, excluding the two byte
916 * length field. (RFC 1035 - 4.2.2. TCP usage)
917 */
918 if (length < 2) {
919 ND_PRINT(" [DNS over TCP: length %u < 2]", length);
920 nd_print_invalid(ndo);
921 return;
922 } else {
923 length -= 2; /* excluding the two byte length field */
924 if (GET_BE_U_2(bp) != length) {
925 ND_PRINT(" [prefix length(%u) != length(%u)]",
926 GET_BE_U_2(bp), length);
927 nd_print_invalid(ndo);
928 return;
929 } else {
930 bp += 2;
931 /* in over TCP case, we need to prepend a space
932 * (not needed in over UDP case)
933 */
934 ND_PRINT(" ");
935 }
936 }
937 }
938
939 np = (const dns_header_t *)bp;
940
941 if(length < sizeof(*np)) {
942 nd_print_protocol(ndo);
943 ND_PRINT(" [length %u < %zu]", length, sizeof(*np));
944 nd_print_invalid(ndo);
945 return;
946 }
947
948 ND_TCHECK_SIZE(np);
949 flags = GET_BE_U_2(np->flags);
950 /* get the byte-order right */
951 qdcount = GET_BE_U_2(np->qdcount);
952 ancount = GET_BE_U_2(np->ancount);
953 nscount = GET_BE_U_2(np->nscount);
954 arcount = GET_BE_U_2(np->arcount);
955
956 /* find the opt record to extract extended rcode */
957 cp = (const u_char *)(np + 1);
958 rcode = DNS_RCODE(flags);
959 for (i = 0; i < qdcount; i++) {
960 if ((cp = ns_nskip(ndo, cp)) == NULL)
961 goto print;
962 cp += 4; /* skip QTYPE and QCLASS */
963 if (cp >= ndo->ndo_snapend)
964 goto print;
965 }
966 for (i = 0; i < ancount + nscount; i++) {
967 if ((cp = ns_nskip(ndo, cp)) == NULL)
968 goto print;
969 cp += 8; /* skip TYPE, CLASS and TTL */
970 if (cp + 2 > ndo->ndo_snapend)
971 goto print;
972 rdlen = GET_BE_U_2(cp);
973 cp += 2 + rdlen;
974 if (cp >= ndo->ndo_snapend)
975 goto print;
976 }
977 for (i = 0; i < arcount; i++) {
978 if ((cp = ns_nskip(ndo, cp)) == NULL)
979 goto print;
980 if (cp + 2 > ndo->ndo_snapend)
981 goto print;
982 type = GET_BE_U_2(cp);
983 cp += 4; /* skip TYPE and CLASS */
984 if (cp + 1 > ndo->ndo_snapend)
985 goto print;
986 if (type == T_OPT) {
987 rcode |= (GET_U_1(cp) << 4);
988 goto print;
989 }
990 cp += 4;
991 if (cp + 2 > ndo->ndo_snapend)
992 goto print;
993 rdlen = GET_BE_U_2(cp);
994 cp += 2 + rdlen;
995 if (cp >= ndo->ndo_snapend)
996 goto print;
997 }
998
999 print:
1000 if (DNS_QR(flags)) {
1001 /* this is a response */
1002 ND_PRINT("%u%s%s%s%s%s%s",
1003 GET_BE_U_2(np->id),
1004 ns_ops[DNS_OPCODE(flags)],
1005 ns_rcode(rcode),
1006 DNS_AA(flags)? "*" : "",
1007 DNS_RA(flags)? "" : "-",
1008 DNS_TC(flags)? "|" : "",
1009 DNS_AD(flags)? "$" : "");
1010
1011 if (qdcount != 1)
1012 ND_PRINT(" [%uq]", qdcount);
1013 /* Print QUESTION section on -vv */
1014 cp = (const u_char *)(np + 1);
1015 for (i = 0; i < qdcount; i++) {
1016 if (i != 0)
1017 ND_PRINT(",");
1018 if (ndo->ndo_vflag > 1) {
1019 ND_PRINT(" q:");
1020 if ((cp = ns_qprint(ndo, cp, bp, is_mdns)) == NULL)
1021 goto trunc;
1022 } else {
1023 if ((cp = ns_nskip(ndo, cp)) == NULL)
1024 goto trunc;
1025 cp += 4; /* skip QTYPE and QCLASS */
1026 }
1027 }
1028 ND_PRINT(" %u/%u/%u", ancount, nscount, arcount);
1029 if (ancount) {
1030 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1031 goto trunc;
1032 ancount--;
1033 while (cp < ndo->ndo_snapend && ancount) {
1034 ND_PRINT(",");
1035 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1036 goto trunc;
1037 ancount--;
1038 }
1039 }
1040 if (ancount)
1041 goto trunc;
1042 /* Print NS and AR sections on -vv */
1043 if (ndo->ndo_vflag > 1) {
1044 if (cp < ndo->ndo_snapend && nscount) {
1045 ND_PRINT(" ns:");
1046 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1047 goto trunc;
1048 nscount--;
1049 while (cp < ndo->ndo_snapend && nscount) {
1050 ND_PRINT(",");
1051 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1052 goto trunc;
1053 nscount--;
1054 }
1055 }
1056 if (nscount)
1057 goto trunc;
1058 if (cp < ndo->ndo_snapend && arcount) {
1059 ND_PRINT(" ar:");
1060 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1061 goto trunc;
1062 arcount--;
1063 while (cp < ndo->ndo_snapend && arcount) {
1064 ND_PRINT(",");
1065 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1066 goto trunc;
1067 arcount--;
1068 }
1069 }
1070 if (arcount)
1071 goto trunc;
1072 }
1073 }
1074 else {
1075 /* this is a request */
1076 ND_PRINT("%u%s%s%s", GET_BE_U_2(np->id),
1077 ns_ops[DNS_OPCODE(flags)],
1078 DNS_RD(flags) ? "+" : "",
1079 DNS_CD(flags) ? "%" : "");
1080
1081 /* any weirdness? */
1082 b2 = GET_BE_U_2(((const u_short *)np) + 1);
1083 if (b2 & 0x6cf)
1084 ND_PRINT(" [b2&3=0x%x]", b2);
1085
1086 if (DNS_OPCODE(flags) == IQUERY) {
1087 if (qdcount)
1088 ND_PRINT(" [%uq]", qdcount);
1089 if (ancount != 1)
1090 ND_PRINT(" [%ua]", ancount);
1091 }
1092 else {
1093 if (ancount)
1094 ND_PRINT(" [%ua]", ancount);
1095 if (qdcount != 1)
1096 ND_PRINT(" [%uq]", qdcount);
1097 }
1098 if (nscount)
1099 ND_PRINT(" [%un]", nscount);
1100 if (arcount)
1101 ND_PRINT(" [%uau]", arcount);
1102
1103 cp = (const u_char *)(np + 1);
1104 if (qdcount) {
1105 cp = ns_qprint(ndo, cp, (const u_char *)np, is_mdns);
1106 if (!cp)
1107 goto trunc;
1108 qdcount--;
1109 while (cp < ndo->ndo_snapend && qdcount) {
1110 cp = ns_qprint(ndo, (const u_char *)cp,
1111 (const u_char *)np,
1112 is_mdns);
1113 if (!cp)
1114 goto trunc;
1115 qdcount--;
1116 }
1117 }
1118 if (qdcount)
1119 goto trunc;
1120
1121 /* Print remaining sections on -vv */
1122 if (ndo->ndo_vflag > 1) {
1123 if (ancount) {
1124 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1125 goto trunc;
1126 ancount--;
1127 while (cp < ndo->ndo_snapend && ancount) {
1128 ND_PRINT(",");
1129 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1130 goto trunc;
1131 ancount--;
1132 }
1133 }
1134 if (ancount)
1135 goto trunc;
1136 if (cp < ndo->ndo_snapend && nscount) {
1137 ND_PRINT(" ns:");
1138 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1139 goto trunc;
1140 nscount--;
1141 while (cp < ndo->ndo_snapend && nscount) {
1142 ND_PRINT(",");
1143 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1144 goto trunc;
1145 nscount--;
1146 }
1147 }
1148 if (nscount > 0)
1149 goto trunc;
1150 if (cp < ndo->ndo_snapend && arcount) {
1151 ND_PRINT(" ar:");
1152 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1153 goto trunc;
1154 arcount--;
1155 while (cp < ndo->ndo_snapend && arcount) {
1156 ND_PRINT(",");
1157 if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
1158 goto trunc;
1159 arcount--;
1160 }
1161 }
1162 if (arcount)
1163 goto trunc;
1164 }
1165 }
1166 ND_PRINT(" (%u)", length);
1167 return;
1168
1169 trunc:
1170 nd_print_trunc(ndo);
1171 }
[mirror] the TCPdump network dissector